How to save thousands of dollars taking care of flap tracks?

Trailing edge flap tracks serve to trailing edge flaps as guide-tracks during flaps extension and retraction.

They undergo the air load, deadweight, and sideload of the flap system that is why they are made of high-strength steel and could weigh up to 1000 pounds depending on aircraft type.

Flap tracks are very expensive components that cost thousands of dollars but either if you want to buy one it will be a challenge to find it on the market. Therefore, maybe you can get it at the aftermarket. Let me know if you do find it.

The bad thing is that the flap tracks are impacted by corrosion. In addition, in my experience, the most of signs of corrosion that are found on the flap tracks surfaces are pitting corrosion. Locations are the following:

·????????Web and Flange Surfaces

·????????Flange Faces for Side Load Fittings

·????????Rear Spar Attachment Location

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How is the pitting corrosion looks:

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Corrosion preventative actions

The first advice to Operator’s CAMO is to control and monitor the effectiveness of the Aircraft Maintenance Program (AMP) or Corrosion Preventative and Control Program (CPCP) in terms of corrosion-related findings on the flap tracks.

The second piece of advice is to Maintenance Engineers and Mechanics who do the lubrication tasks. Please do not ignore the lubrication tasks and do it properly, it is really very important. Always clean and remove the old grease properly, wipe with a clean rag and apply a new one as required in the lubrication task.

Make sure that lubrication fittings are serviceable and grease goes smoothly through it (where applicable).

Keep in mind that the lubrication tasks are very important corrosion prevention tasks that prolong the life of the components and save dollars.

?Repair

The applicable CMMs include information about Allowable Damage Limits (ADL) that covers many technical issues either if the damages/corrosion is out of the limits – no worries Engineers. Based on my experience if you do everything properly you will be able to save the tracks.

The steps are the following:

1.???Be ready to contact OEM to get a repair recommendation

2.???Machine the surfaces removing the minimum amount of material to clean the damages Note: The best way to do Machining is to do it on a CNC machine.

3.???Do an NDT inspection ( the one that is given in the applicable CMM) to confirm the damage/corrosion free condition

4.???Prepare a detailed report with:

·????????measurements of removed material

·????????measurements of remaining thickness

·????????draw everything on the sketch

·????????take high-resolution digital photos of reworked areas

Note: In my experience, OEM does analysis and approves such things if they are acceptable and if corrosion is not extremely severe. I meet 15-20 years old aircraft with the same age of flap tracks and the OEM approved the reworks that were out of the approved documentation limits.

The key points are minimum material removed to eliminate the damages and precise measurements.

5.???Accomplish the repair treating the surfaces as instructed by OEM (usually it is the same procedure as described in the CMM, so you can prepare for that)

NOTE: fabrication of plates or oversized bushings could be required to compensate for the material removed.?

CNC machining of the flap track iaw OEM recommendations