Repainting of Aircraft and Components

1. PURPOSE
The purpose of this process specification is to provide a standard procedure for the repainting of aircraft and components.

2. SCOPE
This specification describes the requirements and procedures for the repainting of aircraft exterior, interior and components including cowlings, thrust reversers, wheels and brakes etc. The processes apply to primarily for aircraft with notes added for components where necessary.

3. SPECIFICATION REFERENCES
a. CAA CAIP Part 2 Leaflet 2-7.
b. FAA AC65-15A Chapter 4
c. Airworthiness Notice No. 82.
d. Applicable Boeing Material Specifications.
e. Paint manufacturers’ Instructions, Processes and Standards
f. Component CMM/OHM.
g. Applicable aircraft exterior markings and colour scheme drawings.

4. MATERIAL REFERENCES
Paints and chemicals listed in Appendix A are for reference; and are not exhaustive. Equivalent products may be used based on the specifications where stated since there are many such products in the market. Obtain the product technical data sheet for guidance prior to using it. Consult Technical Services as needed.

5. SAFETY PRECAUTIONS

a) Carry out all work in adequately ventilated area.

b) Spray paint personnel MUST wear suitable respirators containing filter cartridges for organic vapours when applying epoxy and polyurethane finishes to prevent inhaling spray vapours. Wear rubber gloves, hoods and coveralls so that these materials do not come in contact with exposed skin

c) Where air circulation is insufficient, an air-supplied respirator is required.

d) Observe manufacturer’s safety instructions and precautions at all times.
Avoid prolonged or repeated contact of solvents or conversion coating material with skin. Use gloves, goggles and overalls to prevent contact with stripping material solvents or conversion coating materials.
Note: Do not allow paint stripper to contact skin.

e) Wash body skin or clothing with copious amount of water immediately after contact with any solvent, paint stripper or conversion coating material.

f) Should liquid curing solution or chemicals contacts the skin or eyes, wash skin with soap and water; flush eyes with large amounts of water and seek medical attention immediately.

g) Polyurethane and epoxy coatings are flammable materials, observe fire safety precautions at all times.

h) Ensure aircraft being painted is electrically grounded.

6. GENERAL NOTES

a) Water-Break-Free.
A water-break-free surface is one which maintain a continuous water film for a period of at least 30 seconds after having been sprayed or immersion rinsed in clean water at a temperature below 100ºF (38ºC).

b) A properly cleaned surface is essential to achieve a paint system of a high quality and a long lifetime. When a surface is not cleaned well, problems can occur, include adhesion problems, blisters and pinholes.
– Use clean lint-free cleaning cloths.
– Clean the surface using the “wipe-on-wipe-off” method (use two cloths, one soaked in cleaner to wipe on and the other, a clean, dry cloth to wipe off immediately)
– Do not let the cleaner dry on the substrate.
– Do not touch the degreased surfaces prior to painting (clean the aircraft as the last activity, after masking).
– Thoroughly check the surface for any faults after degreasing.
– Final clean just before painting.

c) Paintshop foreman is to ensure that painting task carried out is adequately defined by technical documents, drawings, data sheets, etc including PS003. Contact Technical Services if information is insufficient.

d) Painter shop foreman is to notify Planning and Maintenance of repainting schedules to plan any structural inspections scheduled including non-destructive inspections that could be better accomplished following paint removal.

e) All painted surface are to be tested/inspected as per para 18.
f) Any stencils/decals can be applied on painted surface after paint adhesion satisfies tape test per para 18.

6.1 PAINT STORAGE AND HANDLING

a) Paints should be mixed, thinned and applied as required in accordance with manufacturers’ data sheets. Do not exceed dry film thickness recommended for best results.

b) Stirring of paints
Where a skin has formed in the paint, it should be removed before stirring. A flat-bladed non-ferrous stirrer should be used.

c) Mixing of paints
Before mixing, check to confirm the right products (base, hardener, and thinner) and that there is enough of each product available to complete the painting procedure. Check data sheet for the correct amount of hardener and thinner to be used.

d) Thinning of paints
The necessary degree of thinning depends on the type of spray equipment
– air pressure
– atmospheric conditions
– kind of paint

The viscosity range or thinning ratio is indicated on the data sheet of each product. Accurate thinning is important for optimum viscosity for best results. Use the correct viscosity cup to check the viscosity as needed.
Note; for tropical conditions, adjust to lower end of viscosity.

e) Straining of paints
All materials should be strained before use. Metal gauze (60 mesh) muslin or three layers of cheese cloth are suitable strainers.

f) Paint must be stored under the right conditions to guarantee the quality. Store the paint in the original unopened containers at a temperature between 5C and 25C. Before using the paint, it must be at the same temperature as the ambient.

g) Paint should be stirred, thinned and strained just before use. The lids of all containers should be wiped clean before opening. Containers should not be left open longer than absolutely necessary, otherwise excessive solvent losses will occur and hardeners may be affected by moisture.

6.2 MASKING FOR PAINTING

a) Masking is to protect various areas from chemicals e.g. stripper and paint including over-spray. Adequate masking is a must around all openings that could admit paints and chemicals e.g. doors, seams, wheel wells.

b) Use aluminium tape to protect specific areas and seams from paint-stripper.

c) Use masking tape to mask paper (tape is not waterproof).

d) Use cello-tape to line out cheat lines and decorative lines.

e) Use kraft paper to protect large areas from over-spray during painting.

f) Use plastic coated paper or impregnated paper to protect from water and chemicals.

g) Use plastic sheet during stripping and spraying in order to mask bulk areas to avoid overspray but ensure that freshly painted surfaces are fully cured before draping with plastic (polythene). This is to avoid locking in of solvent vapour.

Note: Do not use plastic sheets along the border of area to be painted. This is to avoid dust in the wet paint caused by electrostatic charge of plastic sheets.

6.3 EQUIPMENT CLEANLINESS
Keep the application and mixing equipment clean with solvent cleaner e.g C28/15 to avoid clogging of spray nozzle and depositing of foreign material on the coating surface.

If possible, air used for spray gun operation should be from a separate supply. If taken from a general supply line, install sufficient regulators and manifold to buffer abrupt changes or surges in the air pressure. Install sufficient oil and moisture separators in the air system and blow down the air hose at least twice daily (when in use).

7. FLIGHT CONTROL REPAINTING

a) If any flight control surface requires repainting LAE should determine if balancing is involved prior to painting. Such surfaces should be removed from the aircraft to allow re-balancing unless SRM permits re-balancing through calculation.

b) Typically flight control surfaces should be stripped of paint chemically (unless fiberglass/graphite/kevlar composite is involved) or mechanically. LAE is to ensure flight control surface is rebalanced per SRM requirement prior to reinstallation per applicable MM after repainting.

c) LAE is to note down the balancing data prior to repainting.

d) LAE is to coordinate with Technical Services to determine the basic weight and corresponding center of gravity position for flight controls as needed. See also Para 19

e) Fibreglass and graphite/kevlar composite surfaces are to be sanded down using grit 400 or finer abrasive paper or very fine Scotch Brite Pads to remove paint coating.

Note: Do not use paint stripper on fiberglass/graphite/kevlar surface or fiberglass repair patches on aluminum skinned composites

8. SURFACE INSPECTION PRIOR TO PREPARATION
This paragraph applies also to repainting of aircraft components.

a. Ensure aircraft is located in a hangar that is relatively dust free. Electrically ground aircraft per applicable Maintenance Manual.

b. For components, ensure that parts are in relatively dust free area.

c. Spot check the adhesion of the paint as necessary with pressure sensitive adhesive tape 3M 600 or equivalent as per para 18. If the paint comes away with the tape, paint removal is recommended – proceed with para 10 or 13 as applicable. Otherwise go to para 9.
Note: Check at sufficient locations to confirm satisfactory adhesion.

d. Use appropriate tools to remove existing sealant and decals on the surface to avoid scribe marks/lines, particularly on aircraft fuselage lap and circumferential joints. Putty knives, razor blades or any sharp tools are prohibited to be used for sealant and decal removal. Refer to SB 737-53A1262 and AWC ref AWC/Boeing737/001(03) dated 6th May 2003

9. WHEN EXISTING PAINT DOES NOT REQUIRE STRIPPING.

a. Remove any chipped paint around joints and fastener heads. Use aluminum oxide paper grade 280 or finer to feather edges.
Smooth out areas of built-up paint using aluminum oxide paper grade 280 or finer.
Note: Ensure all traces of cleaner are removed by flooding with water and scrubbing with Scotch Brite Pad.

b. Continue scrubbing until a water-break-free surface is attained.

Note:

a) When oil stains or other contaminants cannot be removed by the above means, use a clean cloth moistened with MEK or equivalent to wipe affected surface. Wipe area dry immediately with dry clean cloth.

b) Do not apply excessive amount of MEK which will soften the paint film. If a clean water break free surface cannot be obtained, the paint must be stripped as per para 10 or 13.

c. Allow treated area to dry for about two hours. Ensure no water is trapped at joints, seams, opening etc.

d. Mask as required using masking tape and kraft paper or plastic sheet.
Note: Where masking tape was used on areas to be subsequently painted, ensure all traces of tape adhesive are removed. A clean cloth moistened with MEK may be used. Do not allow any MEK to remain on the surface. Immediately wipe off with clean dry cloth.

e. Proceed to Para 14.

10. WHEN EXISTING PAINT REQUIRES TO BE STRIPPED.

Note: Do not use paint stripper to remove paint on composite materials, fiberglass panels and fiberglass repair patches on aluminum skinned composites.
Use only Environmentally Friendly (EA) paint strippers that do not contain phenolics so as to allow easy disposal.

10.1 MASK FOLLOWING CRITICAL AREAS USING ALUMINIZED PAPER.
For aircraft this must be carried out meticulously to avoid stripper affecting certain material adversely; and stripper getting into crevices and gaps. For components mask areas that are not to be paint-stripped or where it is not desirable for strippers to be trapped.

a. Cabin and Cockpit Windows including window on Doors
Refer to para 10.2.

b Radome & De-icing Boot
Cover all exposed areas if radome and deicer boots if any are removed.

c Door and Openings
Cover all doors gaps and openings with tapes.

Vertical Fin
Cover exposed areas if rudder is removed. Cover fiberglass/composite panels and access openings.

d Wing & Horizontal Stabilizers
Cover wing-to-fuselage fairings and/or areas covered by these fairings; or cover areas exposed if such fairings are removed. Cover also between fuselage and horizontal stabilizer and fuselage-to-horizontal stabilizer attachment areas.

e Fuselage
Mask all cavities, sealed joints and static and pitot points.

f Landing Gear
Mask landing gear with aluminized kraft paper or plastic sheet and tape.

g Ground Support Equipment
Mask all ground support equipment in close proximity and likely to be affected by paint stripper with double layer aluminized paper and tape.

h Plastic or Fibreglass Structures (Including Composite Material)
Cover these surfaces if not removed from aircraft.

10.2 MASKING OF COCKPIT, CABIN AND DOORS’ WINDOWS.
Majority of these windows are made from perspex and will be adversely affected by chemical stripper. Proper masking is therefore critical.

a. Cover all windows surface with aluminized kraft paper or plastic sheet and aluminum tape around the window gaps between fuselage skin and window frame with aluminum tape.

Note: Ensure aluminized kraft paper or plastic sheet is firmly pressed onto the base material by rubbing firmly with a rubber roller over the tape.

b. Cover window with a second layer of larger aluminized kraft paper or plastic sheet and aluminum tape. Ensure that the aluminized kraft paper or plastic sheet overlap is at least 1” over the first layer of aluminum tape before the second layer aluminum tape is applied.

c. Apply third protective screen over all passenger and cockpit windows using curtain of aluminized kraft paper or plastic sheet. This third protective screen is to span lengthwise the fuselage. Overlap where applicable.

Note: Ensure aluminized kraft paper or plastic sheet covers at least two inches above and below the windows.

10.3 PAINT STRIPPING PROCEDURE

a. Preparation
Washing is generally not required except for oily or greasy areas; but it is recommended so that all oils are removed to hasten the action of stripper.
Surfaces to be stripped must be dry and the temperature should be between 15 and 35C. Stripping should not be done in hot sun or rain.
The stripper should be thoroughly mixed in its container before use and it is advisable to keep the container closed when not in use. Keep paint strippers away from heat and sun and take care when opening a container (pressure).

b. Equipment for stripping aircraft
Pump: Use a standard 5:1 or 10:1 stainless steel barrel pump with teflon packing.
Use a stainless steel/teflon hose, fitted with a spray gun and swivel, stainless steel spray wand, and a non atomizing tip.
Test assembled equipment to ensure good working order, with no leaks.
Bristle brushes, squeegees, Scotch-Bright pads etc., normally used in stripping operations can be used with paint strippers.

c. Equipment for stripping components
same as (b) above except the pump.

10.4 PAINT STRIPPER APPLICATION

a. Apply a full coat of paint stripper to the surface to be stripped, working from the bottom up and front to back for the fuselage.
If slippage occurs: apply a mist coat of paint stripper to the surface experiencing adhesion problems, let stand 10-15 minutes and re-apply a full coat.

b. Effect of temperature:
EA Paint Strippers are sensitive to temperature. For best results, the ambient temperature, the surface temperature of the aircraft, must be above 20° C, ideally 30° C rises in temperature are preferred. A 10° C rise in temperature will usually halve the stripping time.

c. Dwell time:
Depending on the stripper being used, paint system, film thickness, age of paint system, original surface treatment, temperature; recommended dwell time will vary from one to four hours. Do not agitate the stripper during dwelling. Do not allow the stripper to dry on the surface. Usually the paint will blister when loosened. Some paints do not blister and should be tested for looseness by scraping very gently with wooden or plastic scrapers. The stripper should be removed from the aircraft when it appears to dry or beads of water appear on the surface in large numbers.

Note:
a) Complete stripping of primer is not required provided remaining primer adhesion to metal can withstand scratching or pass the adhesion test per Para. 18.

b) If primer removal is required or if primer sticks stubbornly re-apply stripper and agitate such areas with white Scotch Brite Pads.

c) Never use steel wool or a steel brush or steel scrapers as tiny bits of steel will become embedded in the aluminium and this leads to corrosion.

d. Remove as much as possible stripper and loose paint residue using non-metallic scrappers and rags. Thoroughly rinse the reworked area with pressurized water hose and scrub. Use nylon brushes with white Scotch Brite Pads to remove residue.

e. For components, spray application may not be necessary but can also be used. Brush application of stripper can be used as alternative.

10.5 AGITATION AND REMOVAL OF LOOSE PAINT

a. Agitate a workable area with a stiff polypropylene brush.
b. Squeegee off all loosened paint.
c. If stripping is not complete, re-apply stripper as necessary per para.

10.4.
d. Hand work with Scotch Brite Pads to remove any residue.
Note: TURCO5948-DPM Cleaner can be used to help lubricate the surface for the Scotch Brite Pads.

10.6 WASH DOWN

a. To remove any remaining paint and/or paint stripper residues, thoroughly wash the entire aircraft or components with a 25% (vol) solution of TURCO 5948-DPM or equivalent, bottom to top, front to back for fuselage.

b. Rinse thoroughly with water, bottom to top and top to bottom, front to back.

c. Inspect bare surfaces for corrosion and other defects.

Note: for components, usually the entire components can be spray rinsed at one go.

11. SURFACE ETCHING/BRIGHTENING

11.1 WASHING PRIOR TO ETCHING (ALKALINE CLEAN)
a. Chemicals
Prepare the TURCO 5948-DPM solution by mixing 1 part TURCO 5948-DPM with 3 parts potable water (a 25% by volume solution)

b. Equipment
Same as 10.3 b

11.2 ALKALINE CLEANING PROCEDURES

a. Apply the TURCO 5948-DPM solution from the keel of the aircraft upward to the top of the aircraft in approximately 20 feet long sections. The length of the section should be expanded or shortened based on manpower and equipment available.

b. After the TURCO 5948-DPM is allowed to dwell for a few minutes, use Scotch Brite Pads to thoroughly agitate, bottom to top, front to back for the fuselage, making sure that the entire surface is completely scrubbed.

c. As one section is being agitated, the TURCO 5948-DPM solution should be applied to the next section.

d. Once a section has been agitated, it should be thoroughly rinsed with high pressure, high volume water (warm is better than cold). The rinsing should begin at the bottom of the aircraft section and work up to the top, then back down again, repeating this sequence until all cleaner is rinsed from the surface. Pay particular attention to seams, door opening, etc., that could trap stripper residue.

e. While one section is being rinsed, the next section should be agitated.

f. This process should continue until the entire aircraft fuselage has been thoroughly cleaned and is water break-free.

Note: For components, spray application as above is usually not necessary. Brush apply TURCO 5948-DPM, agitate with white scotchbrite pads as necessary followed by thorough rinsing with water.

11.3 ETCHING PRIOR TO CONVERSION COATING
This step is optional, and may be omitted for aircraft. It is not necessary for components.

a. Chemicals
Prepare the TURCO METAL-GLO #6 solution by mixing 1 part TURCO METAL GLO #6 with up to 1 part potable water (a 50% by volume solution)

CAUTION:
All High strength steel parts or fittings should be masked off with polyethylene sheeting or other water and acid resistant material using water proof tape.

b. Equipment
Same as 10.3 b

11.4 ETCHING POCEDURE

a. To help eliminate any tendency to splotch the surface, wet the aircraft surface with water prior to the application of the TURCO METAL GLO #6 etchant. Apply the TURCO METAL GLO #6 solution from the keel line upward to the top of the aircraft in approximately 20 feet long sections. The length of the section should be expanded or compressed depending on manpower and equipment available.

b. After the TURCO METAL GLO #6 has been allowed to dwell for 10-20 minutes, using Scotch Brite Pads, thoroughly agitate, bottom to top, front to back for fuselage, making sure the entire surface is completely scrubbed.

c. As a section has being scrubbed, the TURCO METAL GLO #6 solution should be applied to the next section.

d. Once the first section is agitated, it should be thoroughly rinsed with high pressure, high volume water (warm is better than cold). The rinsing should begin at the bottom of the aircraft section and work up to the top, then down again. Continue this rinsing pattern until the water sheets from the aircraft in a smooth, bubble free film. Pay particular attention to seams, door openings, etc., that could trap etchant residue. It is extremely important to follow this rinsing procedure – bottom to top – to avoid streaking the aircraft.

e. While one section is being rinsed, the next section should be agitated.

f. This procedure should continue in a smoothly flowing operation until the entire aircraft has been thoroughly etched and the aircraft has been thoroughly etched and the aircraft surface is completely water break-free.

11.5 INSPECTION
LAE is to inspect for corrosion and for damaged sealant. Replace sealant as required. Inspect lap joints for scribe line damage per relevant documents.
Note: Inform Technical Services of any major corrosion findings.

11.6 CLEANING BARE ALUMINUM SURFACES
Clean bare aluminum surface with 1:1 MEK/toluene mixture or equivalent, and check for water break-free. It may also be carried out for painted surfaces that have been rubbed down as necessary.

12. CONVERSION COATING (CHROMATE) APPLICATION

a) Apply chromate conversion coating Alodine 1200 or 1000 per SRM/MM 51 instructions to produce a coating that meets SRM/MM requirements.

b) Ensure water break free surface during rinsing after the alodine treatment.

c) Allow aircraft/component surface to dry. Wipe and blow seams/lap joints dry to help minimize entrapment of moisture and other contaminants in seams and lap joints.

d) Wipe all surfaces with Cleaner C28/15 or other approved solvent cleaner and clean with two rags, one wet/one dry (“wipe on/wipe off” method). Change often to avoid contamination.

e) Tack with tack cloth before primer application. It is now ready for primer application.

f) Remove all contaminated masking from the aircraft and clean the surrounding environment.

Note: The degreased surface should not be touched with bare hands (wear gloves) and should be protected from any contamination before paint application.
If surface has been allowed to collect dust or other contaminants, wipe with MEK or toluene or other suitable cleaning solvent using low lint cloth or rumple cloth.

g) If the time between cleaning and primer application exceeds 12 hours, solvent clean the aircraft/component surface using a blend of MEK and Toluene or other suitable cleaning solvent. Use clean low lint cotton cloth. Cloth should not be dipped into solvent cans as this will contaminate the clean solvent.
Either pour solvent onto the rag or, using an atomizing spray bottle, spray solvent directly onto the surface and wipe dry. Change cloth frequently.

13. PREPARATION OF PREVIOUSLY PAINTED SURFACES (NOT CHEMICALLY STRIPPED)

a) Wash surface with an alkaline cleaner mixed as specified by the manufacturer.

b) Sand (rub down) painted surface per 13.1.

c) Sand areas that cannot be chemically stripped (i.e. composite areas); and also during paint rework (i.e. removing runs, orange peel, dust etc) or when the maximum re-coatable time has elapsed.

Note: Before sanding, the surface must be free of grease and other contaminants to avoid grease being sanded into the surface, which will cause bonding problems.

13.1 SANDING (rub down) APPLICATION

a. Always wear mask, gloves and goggles during sanding.

b. Electrically ground the surface before sanding to avoid frictional (static) electricity.

c. Use the right type of sandpaper for every paint system. The product to be applied determines the sanding grades to be used.

d. Decide on the successive sanding steps for each paint system remembering not to jump any more than 100 points finer at any time. i.e. from P.180 the finest you could go would be P.280 if you wanted to finish with P. 320. This is to avoid sanding marks in the topcoat.

e. When sanding with a sanding machine, avoid mushroom head rivets, seams and tapes or decals. These areas must be treated by hand, preferably using a Scotch Brite pad Type A (or very fine).

f. When sanding old paint systems, sand to the primer to avoid a building-up of too many layers. Too thick paint systems tend to lose their elasticity after a while, which lead to cracking and peeling-off.

g. With wet sanding (optional) the area has to be kept wet with water and sponge. Change the sanding water regularly. After wet sanding rinse the area thoroughly with clean water and dry off.

a. After wet sanding, ensure the surface is dry before painting. Wait at least 14 hours and use compressed air to remove water from seams and rivets (remove dirty kraft paper or plastic sheet and clean the areas before painting) and use tack-rags to remove the dust from the surfaces

13.2 CLEANING AFTER SANDING
After sanding, the areas and surfaces must be cleaned thoroughly to remove the sanding dust. Use compressed air for seams and other parts where dust can settle. Remove dirty kraft paper or plastic sheet and use tackrags on the surface.

a Remove mechanically the oxide film on paint surface all over and “key” the paint surface using aluminum oxide paper grade 280 or finer.

b Clean the surface using white Scotch Brite Pads and water to remove dust and all contaminants.

c Alkaline clean per Para 11 on reworked surfaces and rinse with water. Ensure water-break free surface. Follow para 12 drying and solvent cleaning method prior to paint application.

14. PRIMER APPLICATION

14.1 APPLICATION EQUIPMENT (Options)

a) Conventional air spray
Atomizing air pressure: 60 to 70 psi
Pot pressure (if applicable): 5 to 20 psi

b) Air assist air-less electrostatic spray equipment
Fluid pressure: 850 – 1,000 psi
Atomizing air pressure: 65 – 75 psi
Tip size: 0.013 inches (0.33mm) or smaller, preferably .011 inch (0.28mm)

c) High pressure air-assist airless electrostatic spray equipment.
Fluid pressure: 2200 – 2500 psi
Atomizing air pressure: 60 – 75 psi
Tip size: 0.009 – 0.013 inch (0.23 – 0.28mm)

14.2 APPLICATION OF PRIMER
Observe General Notes.
Ensure surface is properly prepared and meets water break free test, fully dried and final tack solvent cleaned prior to painting. Apply one cross coat of primer.
Typical dry film thickness: 0.0005” to 0.0008”

Drying time: Re-coatable 1 hour (typical, see data sheet)
Dry to tape 4 hours. (typical, see data sheet)

14.3 ADHESION CHECK
After paint has dried check paint adhesion as per para 18.

15. TOPCOAT APPLICATION

15.1 APPLICATION EQUIPMENT

As per para 14.1

15.2 APPLICATION

Note: Observe General Notes.
Topcoat must be applied within 48 hours of primer application. If 48 hours is exceeded sanding of primer with scotchbrite pad (white) is necessary.
Apply one cross coat, or two coats of topcoat as required to achieve the desired finish.

Drying Time: Re-coatable 1 hour (typical, see data sheet)
Dry to tape 4 hours (typical, see data sheet)

15.3 ADHESION CHECK
After paint has dried check paint adhesion as per para 18.

16. CLEARCOAT APPLICATION
Topcoat must be treated with Aerodur Clearcoat UVR within 4 to 48 hours of topcoat drying if Clearcoat is called out in the drawing.
Apply two cross coats of Aerodur Clearcoat UVR over the topcoat.
Drying Time: Dry to tape 10 to 12 hours.
After paint has dried check paint adhesion as per para 18.

17. REWORK OF IN-PROCESS DEFECTS

a) In-process defects such as overspray, orange-peel, runs or sags occurring in the primers or in the topcoat which are considered excessive may be reworked by dry sanding with 240 grit or finer abrasive paper followed by wet or dry sanding with 380 – 400 grit or finer abrasive paper. (See para 13)

b) Sanding should not be attempted until the coating being reworked is sufficiently dry to permit sanding. This may take up to 8 hours depending on the weather.

c) After the sanding is completed, the surface has to be cleaned to remove the sanding dust. Use a cloth moistened with solvent cleaner and re-apply primer or topcoat, as required.

d) For some in-process defects such as overspray, runs or sags in finishing coats, it is possible to polish them away. Do not use ammonia-based polishes. Ammonia will destroy the gloss of most aircraft finishes. Only on high-gloss finishes, sags and runs can be removed by wet flatting with 1200 grit wet and dry paper and using clean water and soap. Use a non-ammonia polish with a fine cutting compound to remove the flatting scratches and a final cream polish to revitalize the gloss of the required area.

e) This operation can be done either by hand or polishing machine. When using a machine, a sponge head should be dampened down with water before applying the polish. This decreases the “burning” of painted surface.

18. QUALITY CONTROL

18.1 ADHESION TEST
Note: Tape adhesion test is to be carried after paint is fully dry. Refer to manufacturer data of specific paints used for “dry to tape” time.

a. Apply 1 inch wide 3M 600 Transparent Film Tape or equivalent to painted surface 1.5 inches long. Repeat this test with fresh tape on at least 3 locations some distances apart.

Note: Shelf life of tapes shall not be more than 6 months old from date of manufacture or as per manufacturer’s shelf life. Storage conditions at 70°F (21°C) and 40-50% relative humidity is recommended.

b. Press tape down firmly (5 pound minimum pressure)

c. Remove the tape within 5 minutes in one abrupt motion perpendicular to the paint surface.

d. Examine area for paint coating failure. Check tape for coating separation.

e. If there is an evidence of paint coating separation, determine extent of defective area and repeat para 8 when necessary.
18.2 WATER-BREAK-FREE-TEST
This must be thoroughly carried out for all large surfaces to be repainted to ensure good paint adhesion. Utmost care is to be exercised not to contaminate areas and tested to be water-break-free.

18.3 POST PAINTING INSPECTION

a Inspect painted surface visually to confirm no defects e.g. orange peel, runs, sags, contamination

b Ensure all mandatory and maintenance markings are re-installed correctly.

c Painter and LAE are to inspect for any damages to transparencies, composites and sealants by solvent and paint removers due to inadequate protection and/or the retention of these products in crevices

TECHNICAL SERVICES DEPARTMENT (AVIATIONS)

SERVICES PROVIDED BY TECHNICAL SERVICES

Services provided by the Technical Services Department are briefly described here.  The following listing is not meant to be exhaustive. Typically, Technical Services provides the services to

  1. a) Maintenance department and Maintenance Control Centre when
  2. Technical data available does not meet operational requirements;
  3. Defects exceed limitations laid down in manuals;
  4. Necessary spares or tools are not available,
  5. Recurring defects need some investigation/solutions,
  6. Clarifications are needed on technical matters/data,
  7. Modifications are needed to improve economics or to minimise problems,
  8. Projects need technical study or information.
  1. b) Project and Planning department when
  2. Modifications are required to meet airworthiness and/or business requirements;
  3. Technical support when aircraft is in maintenance check at third party,
  4. Technical support for third party aircraft undergoing maintenance,
  5. Engine management including modification requires study/input,
  6. Difficulty is faced in maintenance program; or
  7. Projects need technical study or information.
  1. c) Flight Operations
  2. In issuing, maintaining and controlling aircraft weight and balance reports, load and trim charts,
  3. When technical data/clarifications are needed related to performance issues,
  4. When modifications are required to meet operational requirements,
  5. When projects need technical study or information.
  1. d) Flight Operations and Maintenance departments in
  2. Maintaining aircraft Dispatch Deviation Procedures Guide (DDPG) and Dispatch Procedures Manual (DPM) which incorporate the customized Minimum Equipment List (MEL),
  3. Updating test flight performa,
  4. Vetting test flight results prior submission to local authority,
  5. Analysing flight safety problems.
  6. e) Procurement & Spares when
  7. Parts interchangeability and substitution are desired,
  8. Components need repair instructions, drawings and other advice,
  9. Clarifications needed for technical matters.
  1. f) Flight Operations, Procurement & Spares, Quality Assurance, Project & Planning departments in
  2. Updating Maintenance Schedule,
  3. Managing Technical Publications,
  4. Evaluation and interpretation of Airworthiness Directives, Service Bulletins and other technical matters.
  5. SSUFDR recording readout.
  1. g) All relevant departments in

Managing the Reliability Program including engine trend monitoring, and

Changes in Maintenance Schedule.

  1. h) Other third parties typically in aviation that require technical support and work similar to those described above.

COSTING OF THE SERVICES

Technical Services shall liaise with Project & Planning and Finance departments to determine the rates to be charged to customers for services rendered.  Typically this will consist of regular services and ad-hoc project type work.  In most cases, charges would be based on manhours spent by Technical Services Engineers.

The Maintenance Dictionary of Terms

The Maintenance Dictionary of Terms

We all know that we have our own language in maintenance. I have written blogs about “hog” pliers, “the angle of the dangle”, etc.  I am sure that we all have our own contributions to the “Maintenance Dictionary”. It is an ever evolving language that will change time and time again as long as there are guys swinging wrenches.

There is one guy at our shop who has coined his fair share of terms that we use here in OAK. I would like to share these terms with you guys and maybe you guys have some terms you would like to add to our Dictionary. Thank you to the mechanic I will call- Non-Sched for your library of terms.

Your Turn in the Barrel                                       It’s your turn to work the broke plane.

Smoking a Turd in Purgatory                               What ever you are doing is going to damn you to hell.

Quick Flip                                                            Working a shift-being off for 8hrs and coming back.

IFE                                                                        In Flight Emergency

Change the Big Part                                              R/Ring the largest, most expensive piece in the system.

Rag Wrench It!                                                      Wiping a leak down and calling it good.                                                                                Derogatory  remark. “All he did was rag wrench it!”

Change the Carburetor                                          Change the MEC or HMU on an engine.

Putting out Fires                                                    Solving all the issues pilots have.

Take it to the Box                                                   Take the plane to the run up hole.

Men Who Stare at Planes                                      Mechanics who don’t work very hard.

Push it to the Pad                                                   Take the plane off line-ground it.

Fielding Gate Calls                                                The process of answering and doing gate calls

Make it go Bye Bye                                               Fix it and get it out of town.

Your on Deck                                                        You are next up for a call.

Is it Taco’d?                                                            Is it messed up beyond repair?

Premium Call                                                         A very easy gate call

Jamalphed                                                              All messed up

Not Enough Bounces                                             Not enough landings

Dolls Eye Indicator                                                 Ball indicator

GSP                                                                         Gravy Sucking Pig

There are more but some are not easily translated into something that would make sense to anyone but a person who was around at the time, like “Swivel Hips”.

All these terms are an amalgamation of years of airline experience, people, and actions. These are terms that are used almost daily here in OAK and will be with me long after my time at SWA is over. Some may think that these types of things don’t mean much but I argue that they do. If you know that it’s “your turn in the barrel” then you may be “changing the big part” because the old one is “taco’d”. When you are done you can “take it to the box” and if your good and not just a “man who stares at planes” then you can “make it go bye bye”. And that’s what we are all about.

 

What are the similarities and differences between boeing 737 and airbus A320 ?

Similarities and differences…?

Among the biggest simmilarity is that they are two aircraft of the same class and in direct competition with each other. In terms of capacity here is how the models compete:

A318 vs 737-600
A319 vs 737-700
A320 vs 737-800
A321 vs 737-900

In all those cases Boeing has a slight edge on seating capacity. Also the Boeings are a little lighter. 737’s also have a slighty better seat per mile cost. In terms of sales, both are more or less equal, slightly favouring Boeing, except for the A321 vs the 737-900, where Airbus has outsold a bit more significantly. Boeing has however sold more 737’s than Airbus 320 family aircraft, due to sales of previous generation 737’s

The 737 was designed very low off the ground as it is adequate to operate out of unprepared airfields, where it can deploy its own inbuilt airstairs. The A320 family of aircraft sit much higher off the ground.

In terms of powerplants, Airbus gives its customers the great advantage of choice! They can chose between the CFM56 or the IAE V2500. While the 737’s all come standard with CFM56’s. Most Airbuses use the CFM56 engines so its fair to say both aircraft actually operate the same engine! This is not entirely true, since they operate different versions of the powerplant, but it is essentially the same engine.

Even though the 737’s have a better economy, there are lots of other factors, which count in the decision of which one to buy. If the airline already operates other Airbus types, such as the A330 or A340, then A320’s will fit in very well and they might save a lot of money on training, since the aircraft have almost identical controls. The conversion from the A340 to A320 is about a week! Boeing is trying to follow that too now, but still their types are not as common.

Differences:
Well lots of technical differences obviously. But essentially the aircraft have very simillar performances. One notable difference is the Fly By Wire control system on the A320. The aircraft even trims itself! The 737 is a bit less automated and employs a standard control system.

Visually there are lots of differences and I hope you weren’t asking about them.

Hope this all helps a bit!

  • Physically they are very similar, being low wing twin jet engine passenger aircraft with seating for approximately 160 passengers. The fin shape is the easiest difference to spot at an airport, the Airbus one is straight lined at the leading edge and the Boeing one has a fillet on its leading edge. Generally the Airbus also has wing tip ‘vertical extensions’ and the Boeing does not.
    0% 0 Votes
  • The Airbus A320 has two engine options IAEV 2500 and the CFM 56. While the Boeing 737 has a sole powerplant from the Series 300/400/500 and next generation 600/700/700ER/800/900/900ER. The 100/200 has Pratt Whitney JT8D engines.

    The 737 has sold more aircraft than the Airbus Family by really far.

    the 737-900ER has more range but the A321 can fit more passengers

    the 737 has much more bigger winglets
    both A320 and 737 have winglets

    A320 has longer legs

    737 have been out longer than the A320

    THE 737 is made in the United States

    While the A320 is made in Europe and assembled in Toulhouse France

    they are both narrow bodies

    and are both very ecconmical

    LCC / Low Cost Carriers tend to use the Airbus Industrie A320

    The A320 family is cheaper than the 737 to purchise

    the 737 has marginal trans alantic capibility while the Airbus A320 DOSE’NT have trans alantic capbility

    the airbus has a common air frame with A300/A310/A330/A340/A380

    While the Boeing has a common air frame with the 707/717 tanker transport not the DC-9 version/727

    the 737 has eyebrows which help for the visibility

    while the A320 family doesn’t

    • 5 years ago
     
     
     
    In addition to everything said above, I would add from a pilot who has flown both that I prefer the yoke control to the side stick, and comparing the Next Gen Boeing to The A320 series, the cockpit is roomier in the Airbus and has more creature features than the Boeing. Over all I would pick the Boeing. Just personal preference.
    • 5 years ago

     

     

    Similarities-

    1)Both uses the same SNECMA CFM-56-7B engine producing 20,000LBS thrust

    AIRBUS A320

    AICRAFT DIMENSIONS
    Overall length 37.57 m. 123 ft. 3 in.

    Height 11.76 m. 38 ft. 7 in.

    Fuselage diameter 3.95 m. 13 ft.

    Maximum cabin width 3.70 m. 12 ft. 1 in.

    Cabin length 27.51 m. 90 ft. 3 in.

    Wingspan (geometric) 34.10 m. 111 ft. 10 in.

    Wing area (reference) 122.6 m2 1,320 ft2

    Wing sweep (25% chord) 25 degrees 25 degrees

    Wheelbase 12.64 m. 41 ft. 5 in.

    Wheel track 7.59 m. 24 ft. 11 in.

    BASIC OPERATING DATA
    metric imperial

    Engines two CFM56-5 or IAE V2500 two CFM56-5 or IAE V2500

    Engine thrust range 111-120 kN 22,000-27,000 lb. slst

    Typical passenger seating 150 150

    Range (w/max. passengers) 4,800 (5,700) km. 2,600 (3,000) nm.

    Max. operating Mach number (Mmo) 0.82 Mo. 0.82 Mo.

    Bulk hold volume – Standard/option 37.41 m3 1,322 ft3

    DESIGN WEIGHTS
    metric imperial

    Maximum ramp weight 73.9 (77.4) tonnes 162.9 (170.6) lbs. x 1000

    Maximum takeoff weight 73.5 (77) tonnes 162 (169.8) lbs. x 1000

    Maximum landing weight 64.5 (66) tonnes 142.2 (145.5) lbs. x 1000

    Maximum zero fuel weight 61 (62.5) tonnes 134.5 (137.8) lbs. x 1000

    Maximum fuel capacity 23,860 (29,840) Litres 6,300 (7,885) US gal.

    Typical operating weight empty 42.4 tonnes 93.5 lbs. x 1000

    Typical volumetric payload 16.6 tonnes 36.59 lbs. x 1

    • 5 years ago

 

Why are there no winglets on the Boeing 777?

Why are there no winglets on the Boeing 777?

Flying Flying on the Boeing 777
Tuesday, 11 December 2007 20:37

Hello Capt Lim,

Why doesn’t the Boeing 777 have winglets?

Razaq

Hi Razaq,

This topic is also covered in my previous FAQ and here are some more information extracted from an article by George Larson in the Air & Space Magazine.

Basically, winglets reduce wingtip vortices, the swirling airflows formed by the difference between the pressure on the upper surface of an airplane’s wing and that on the lower surface. High pressure on the lower surface creates a natural airflow that makes its way to the wingtip and curls upward around it. When flow around the wingtips streams out behind the airplane, a vortex is formed. These twisters represent an energy loss and are strong enough to flip airplanes that fly into them.

Winglets produce a good performance boost for jets by reducing drag, and that reduction could translate into slightly higher cruising speed. The Boeing 747-400s have winglets. The Boeing Business Jet, a derivative of the Boeing 737, has a set of the firm’s eight-foot winglets as well.

After the energy crisis in 1976, Richard Whitcomb, a NASA aerodynamicist, in a research, compared a wing with a winglet and the same wing with a simple extension to increase its span. As a basis for comparing both devices, the extension and the winglet were sized so that both put an equal structural load on the wing. Whitcomb showed that winglets reduced drag by about 20 percent.

A wing with high aspect ratio will provide longer range at a given cruise speed than a short, stubby wing because the longer wing is less affected by the energy lost to the wingtip vortex. But long wings are prone to flex and have to be strengthened, which adds weight. Winglets provide the effect of increased aspect ratio without extending the wingspan.

If winglets are so great, why don’t all airplanes have them? In the case of the Boeing 777, an airplane with exceptionally long range, the wings grew so long that folding wingtips were offered to get into tight airport gates. Dave Akiyama, manager of aerodynamics engineering in Boeing product development, points out that designing winglets can be tricky because they have a tendency to flutter. And so the computer came up with a Boeing 777 wing design that did away the winglets and fly just as efficiently.

Can you please explain what exactly is fly-by-wire?

Can you please explain what exactly is fly-by-wire?

Flying Flying on the Boeing 777
Wednesday, 04 January 2006 02:01

Hi Capt Lim,

Wishing you a Happy New Year 2006!

I know it is really embarrassing for me to ask this, but can you please explain what exactly is the fly-by-wire system?

Thanks a lot.

Alaric.

Hi Alaric,

Very simply, “wire” here means “electric or electronic signals”.

In the past, the flight controls of planes were connected to the pilots by cables ( just like those strings steering the rudder of a motor boat). For instance, on the old Boeing 707, when the captain wished to climb, he pulled the flight control wheel up (needed quite a bit of force). This in turn moved the elevator. That movement was possible because of cables that can be hundreds of feet long. Yes, these cumbersome, lengthy and heavy cables are now replaced by electronics or electrical wires. Hence, the term “fly-by-wire” (FBW)

Today, when I wish to perform a climb on the Boeing 777, I merely pull back the control wheel gently, the signal is transmitted instantaneously to the elevatiors near the tail. Well, there are no cables running up from the cockpit to the back (about 209 feet long) to perform this climbing action.

Welcome to the world of electronics! Ah…really, there is nothing to shout about! FBW technology was introduced in the military aviation in the 1940s and the Concorde was the first fly-by-wire airliner. This technology was slow to be introduced widely into the commecial airlines until the Airbus A320 took the lead in 1984. Since then, all the subsequent Airbuses are designed with FBW technology whereas Boeing only began to work on this in 1994 on the 777s.

Flying by wires means that there are no direct mechanical links, cable or hydraulics, between the pilots and the control surfaces. This eliminates weight and reduces complexity in removing cables, linkages and hydraulic tubing. It also facilitates the use of software to be incorporated into the autopilot system for safer flying.

Should I fly the Airbus A340 or Boeing 777?

Should I fly the Airbus A340 or Boeing 777?

Flying Flying on the Boeing 777
Thursday, 28 September 2006 12:03

Dear Captain Lim,

Thank you very much for your answers to lots of questions about flying. It does help me fight my fear of flying again. However, recently I read an article of CNN.com on *Planes still flying with same problem as TWA 800* and I am nervous again. Especially this paragraph: *While the FAA has not yet made a final decision, Boeing, which has built nearly three-fourths of the jetliners in use around the world, told CNN it will install a nitrogen safety system on its new planes — with or without an FAA mandate — because it is “the right thing to do.”*

Does that mean right now it is in the wrong? I am worried about this.

Should I take Airbus instead? Or Maybe Boeing 777 is totally different from Boeing 747 series, thus is not under that threat? Pease help me figure this out; I am about to buy a ticket by next Tuesday. I have to choose which Airline to take me back to China (either Airbus340-300 or B777-200ER, after ruling out B747-400 by myself).

Thank you!

Sincerely,

Fong

Dear Fong,

Yes, in the TWA 800 problem, the FAA had determined that the Boeing 747 was the victim of a center fuel tank explosion, most likely caused by a spark in its vapor-filled center tank.

The Boeing 747 plane involved was in fact the first variant, designated as B747-100, built in 1971, not the later generation B747-400, which most people would be flying on today.

FAA now wants all large US jetliners to be equipped with a nitrogen safety system to prevent similar explosions by removing oxygen from fuel tanks. This would effectively require the new safety system to be fitted in all new planes coming off the assembly line, as well as the retrofitting of about 3,800 other large jets.

Many airlines had opposed the FAA*s recommendation and stated that its statistical assumption ? “without its recommended safety changes, four more TWA-type disasters are likely to happen over the next 50 years” – was ?fatally flawed?.

Boeing said that none of the recovered fuel system components showed any evidence of having sparked the events suspected of blowing up the airliner. Similarly, no evidence was found that any of the B747-100*s fuel quantity indicators, probes or wiring was the culprits. Nevertheless, the investigation had prompted some improvements in design, maintenance and/or inspection across the Boeing fleet. So it appears that there is still a lingering doubt as to the actual cause of the spark that led to the crash.

Of course, I believe what Boeing had told CNN that it would install a nitrogen safety system on all its new planes because it is “the right thing to do” is obviously a public relation exercise to promote the future sales of their Boeing planes, especially the Boeing 787 and B747-8 planes.

I cannot comment on as to whether they are now in the right or wrong but I think Boeing planes are just as safe any other planes around ? and I am happy with the Boeing 777 that I have flown for the last 8 years or more now.

You should not be worried whether you are going to fly a Airbus A340, a Boeing 777 or even the Boeing 747-400. They are all equally safe as I often tell fearful flyers in my site that flying in the modern commercial jetliners is very safe ? you have about one in 12 million chances of getting involved in fatal air accident. I will fly on any of them as I am not worried at all :-)!

Some questions relating to winglets and speeds of the Boeing 777.

Some questions relating to winglets and speeds of the Boeing 777.

Flying Flying on the Boeing 777
Tuesday, 11 December 2007 20:51

Dear Captain Lim,

Thanks for answering my previous questions. I have an interview with Cathay Pacific coming up shortly. So all the help I can get will be appreciated.

On the winglets, approximately how much drag do they reduce in terms of percentage?
What is the difference between maximum range cruise and long range cruise?
What is the relationship of V1, VR and V2?

I really appreciate your time and concern.

Thanks,

Zakk

Hi Zakk,

1. On winglets, they can reduce the drag by as much as 20 % on some wings but you can do further researches on them. I will give you all the links below:-

www.aviationpartnersboeing.com

www.b737.org.uk/winglets.htm

www.visionengineer.com/aero/winglet.shtml

www.airspacemag.com/asm/mag/index/2001/as/htww.html

www.fluent.com/about/news/newsletters/01v10i1/a2.htm

2. Very briefly, maximum range cruise gives the best range in the power setting to achieve the furthest distance with the available fuel you have on board the airplane. It is used when the pilot realized that the airplane is low on fuel. It is based on zero Cost Index.

Long range cruise is the power setting in the Flight Management Computer (FMC) which gives the best cruising speed for long range. It is based on the speed which gives 99 % of maximum fuel mileage at zero wind. This power setting is used to good advantage if you have a favorable tail wind.

3. V1 is the Takeoff Decision Speed used as a reference in deciding whether a take off is to be continued or aborted when an engine failure occurs.  VR or Rotation Speed is the airspeed when the pilot begins to rotate the aircraft to lift off attitude, normally at the rate of 2 to 3 degrees per seconds, depending on the aircraft certification.

V2 is the Takeoff Safety and Initial Climb Speed. This speed is achieved prior to 35 feet above ground level. It is attained as a result of proper rotation and lift off procedures. It allows the aircraft to maintain a specified gradient in the climb-out flight path.

What is the typical climb profile of a Boeing 777?

What is the typical climb profile of a Boeing 777?

Flying Flying on the Boeing 777
Monday, 07 January 2008 20:23

Hi Capt Lim,

I have one question with reference to the basic climb performance of a typical
Airliner like a Boeing 777. If you visualize the vertical view of the climb profile of an aircraft, after takeoff and before the top of descent I see a constant altitude segment. What is the exact reason for it?

Is it because the Aircraft is under maximum gross weight and is incapable of
reaching it’s cruising altitude directly or is the pilot trying to avoid a particular region so he needs to have a constant altitude segment before cruise?

If you have a choice would you prefer to climb to the cruise directly
or do you prefer to step-climb and why?

Thanks and Regards,

Srihari J

Hi Srihari,

It is not true to say a typical Boeing 777 profile has a constant altitude segment. Perhaps the profile you mentioned covers a short sector of a 3-to-4 hours flight where further step-climbs have no economical advantage. I do a lot of long haul flights from the Far East to Europe of around 12 to 13 hours duration where there are at least 3 step-climbs. With a heavy aircraft (around 286,000 kg), the computer calculates the optimum altitude of 31,000 feet initially.

As the aircraft climbs, the computers recommends a step-climb to 35,000 feet when the aircraft weight reduces as a result of fuel burnt (a Boeing 777 consumes around 6000 to 7000 kg of fuel per hour depending on the
weight).

Three quarter way through the flight when the aircraft is about 55,000 kg lighter because of the fuel consumed, the computer will recommend a further climb to 39,000 feet. Looking at this climb profile, it is not true to say that a typical Boeing 777 has a flat segment from the top of climb to the top of descent.

Pilots will rely on the Flight Management Computer to choose the optimum level to climb to. If the pilot fly at any level other than recommended, the airplane will burn more fuel and hence uneconomical to cruise at.

When you mentioned about a constant altitude before cruise, I am wondering if you are referring to the initial accelerating altitude of 1000 feet or the 3000 feet (depending on the airport), which is part of the noise abatement procedures.

Why Boeing 777?

Why Boeing 777?

Flying Flying on the Boeing 777
Tuesday, 08 January 2008 19:23

Why Boeing 777 ? How about Boeing 747, A330/340 or MD-11?

Hi Capt Lim.

1. First let me commend you on presenting an exceptional site with honest, practical and in-depth information on one of the newest jets in commercial service.

2. I have a question which I hope that perhaps you can answer adequately because I can’t. This is namely…

“Why 777? Why did Boeing spend an enormous amount of money to develop an airliner whose size, capacity and cost class can be served by the 747?”

The 777 is not a cheap aircraft. They cost 238 million a piece on the average compared to 215 million for the 747. The GE90, late model PW4xxx and RR Trent engines in the 86,000 to 106,000 lb thrust class are roughly 15 million each in themselves. The 777 does not seem to out-carry the range or convenience of the late model 747s (due to ETOPS routing requirements). The last is a problem, because one of the big application of big wide bodies is in long haul over the water flight, something which the A340 does and the 777 may not be allowed to do even if it ought to be fully capable of doing safely in the absence of regulatory hurdles. The 777-300s are also in fact longer than the 747.

If the 747 didn’t exist, the 777 makes good sense, but the 747 has been flying for over 30 years so its paid for and it is not outdated in any sense. If the idea is to reduce unwanted seat capacity and increase efficiency for operators why not a reduced-weight 747 without the top deck and with 4 smaller engines of the CFM56/IAE-V2533 class? It’ll be cheaper than to do a ground up aircraft. If a ground up aircraft is mandated why shouldn’t it also have a 4 engine option like the A340? In fact, the 777 is not really too far from the size, thrust and capacity or class of the MD-11, a product Boeing saw fit to promptly discontinue.

3. I am not an airline professional, so do forgive me if the above is completely idiotic.

4. Thank you, and finest regards.

Dwight Looi

Hi Dwight Looi,

It is nice to have an interesting question from someone who has a good knowledge of commercial airplanes.

Firstly, before I express my opinions, I wish to state that I am not an employee of Boeing and I don’t claim to endorse their products.

Why Boeing 777? Simple. If you are conservative and not market-driven minded, you would always continue to drive an old car. In which case, the Manufacturer of your old car may have to close shop very soon! That is why manufacturer of cars keep on improving their latest models to suit the customers’ needs. Having said that, airplane manufacturers do likewise if they want to survive in this competitive world.

The Boeing 747 is about 30 years old. Although the later models of the Boeing 747’s have quite advanced avionics like the Boeing 777’s, the basic airframe design is still rather old.

So, why not Boeing 777? It is the first airplane to be digitally designed by computers and the finished product is hence the best in efficiency and quality. Flying the Boeing 777 from the point of view of a pilot is like driving the latest model of the Mercedes than that of an old Jaguar!

You said that the Boeing 777 does not seem to carry out the range and convenience of the later model of the Boeing 747’s. Just for your information, the Boeing 777 comes in 5 models and they seat between 301 to 368 passengers in three class configurations. So they are very flexible and suitable for routes that are mainly of those capacities. They have a range of 5210 nautical miles (9469 kilometers) to 8810 nautical miles (16316 kilometers), a range that is almost just as good as the Boeing 747’s!

The ETOPS requirement may be a slight disadvantage initially, but having achieved the 180 minutes approval from the FAA in May 1998, many destinations are within reach of the Boeing 777’s.

You are also right that the Boeing 777-300 is longer than the Boeing 747.

Why spend money on modifying the Boeing 747’s to reduce the unwanted seats and getting rid of the top deck when the money would be usefully spent on introducing a newer model? It does not make economic sense.

The MD-11 is not a very successful airplane and despite their extra engine it has lesser passenger appeal when compared to the Boeing 777.

It is true that Boeing did not take up the 4-engines option for the 777 like they did to the Airbus 340 airplanes. Despite its two engines, a survey was conducted in 1999 and 2000 worldwide, and it was found that the Boeing 777 was preferred by more than 75 % who flew aboard the Boeing 777 and Airbus 330/340 airplanes.

As a pilot who has flown on both types of airplanes, I still prefer the Boeing 777 in terms of comfort, spaciousness and best of all, the airplane can take turbulence better than the Airbus 330/340!

Hi again,

1. Thanks for the reply!

2. I forgot to mention in the original message, but the 777 also seems to be heavier and needing more power (hence more fuel burn?) than the A330 or A340. The 330 seems to be happy with two CF6/RB211/PW4062 class engines with roughly 120,000 lbs total. The A340
doesn’t seem to really need more thrust than the 330, just that it has 4 fans of the smaller mid-30,000 lbs class CFM56 engines. The 777 with a similar carrying capacity and perhaps marginally higher cruise speed needed a minimum of two GE90/Trent800/PW41xx class giants of 172,000 lbs minimum and up to 212,000 lbs with some later options.

Is this a sign that the 777 airframe is overweight compared to the A330/340? Is it less aerodynamically efficient or that Boeing simply wanted a better climb-to-altitude performance and a higher cruising speed? The latter has never been an Airbus priority especially with the 300/310/320 generation airplanes which are typically 0.1 Mach slower than their Boeing or MD contemporaries.

3. Boeing, it seems to me is in a problematic position. For 30 years it has equal of better products to Airbus in every category. And it has a monopoly of the 747 class market. Now the A330/340 seems to be offering a more economical solution (priced at 85% the 777 price) for the 2nd-tier wide body market. And Boeing is about to lose its 1st-tier wide body crown
to the A380. This is reflected in the number of deliveries from Boeing; 508 in 2000, 380 in 2001 and a projected 275 in 2002. Airbus claims that it will deliver 300 this year surpassing Boeing for the first time in total units.

I must admit that Airbus has the unfair advantage of having European tax payers take a good bit of their losses incurred in their established practice of undercutting Boeing and MD in the past, but that doesn’t change the fact that Boeing now has a big problem. It has lost dominance and it doesn’t know how to get it back.

The Sonic-Cruiser may or may not be a good idea. Frankly, I doubt if 0.1 Mach higher cruising speed is worth half the capacity and twice the engine power. But even it is, it is still a vapor plane that is far from the first test flight. The secondary proposal of an ultra efficient long haul medium capacity design for slower cruise at above 45,000 feet is even more of a vapor aircraft. Amidst all these, 911 certainly didn’t help, but I think its a still a mistake to surrender to the A380 and then not know what to do next.

4. Finest regards.

Dwight Looi

Hi Dwight Looi,

Okay, you are well versed in all the details as to the performance and technical specifications of the Boeing 777 vis-à-vis the Airbus 330/340. You are correct in certain aspects, but the Boeing 777 is not less aerodynamically efficient although it is slightly heavier.

Remember, I mentioned above that the Boeing 777 can take turbulence better than the Airbus 330/340 ? This is because the Boeing 777 wings are more rigid and sturdy than the Airbus 330/340 lighter wings. This consequently contributes to the ‘rougher ride’ when the Airbus 330/340 is caught in turbulences.

True, Boeing may be losing the market share to Airbus Industrie. I suppose it is up to them to come up with more innovative strategies. The Sonic Cruiser may be one of them but its success is left to be seen in the future.