ATA 57 Wings

1 - Shims used on the outboard flap carriage assies (track 1-2-7-8) 737-3/4/500 :

p/n 69-77878-1 thickness 0.016 inch = 0.40 mm

p/n 69-77878-3 thickness 0.032 inch = 0.81 mm

p/n 69-77878-5 thickness 0.063 inch = 1.60 mm

p/n 69-77878-7 thickness 0.125 inch = 3.17 mm

See IPC 57-52-00-06

p/n 69-77878-2 thickness 0.016 inch = 0.40 mm

p/n 69-77878-4 thickness 0.032 inch = 0.81 mm

p/n 69-77878-6 thickness 0.063 inch = 1.60 mm

p/n 69-77878-8 thickness 0.125 inch = 3.17 mm

See IPC 57-52-00-06

On the classic 737 you will (almost always) find this panel attachment to the fuselage side with lots of play. The bolthole will be elongated and the screw will be very loose, thus causing the panel to have play in upward direction. You can install a thicker screw with a dimpled washer, or replace the attachment bracket completely, depending on the situation. It's just an item you should not overlook during inspections. See picture for location.

On the NG 737 the fixed aft wingpanel between the flaps (or better, between the inboard and outboard spoilers) can have lots of play on the attachment point with the 2 bolts. This panel will then have play on that area causing the serrated plates and bolts to wear out. New hardware and a re-adjustment of the panel is then necessary. See picture for location.

4 - Loose fixed aft lower wingpanel between pylon and inb flapfairing. 737-6/7/8/900

When inspecting the trailing edge area on the 737 NG, pay attention to the aft lower panel between the pylon and the inboard flapfairing. The attachment strip (waved shape) on the upper side of this panel can have cracks causing a loose panel at the fwd side. You can find it easily by pushing the panel upwards. When this is possible, the attachment strip is probably cracked/loose around the attachment rivets. See pictures for clarification. See IPC 57-50-00-30

When installing flaptrack 3 or 6, the AMM (27-51-27) states that you first install and tighten the fwd 3 bolts and then the aft 3 bolts. But then it is often impossible to install the aft bolts, especially the middle one with the torque washer. It even happens that you cannot get the required torque on the aft bolts, and the torque washer will keep turning even with the maximum torque applied.So this tip is to install the aft bolts first and torque them. Then try to install the fwd bolts and torque them. It can save you a lot of time. See pictures below for the location of the bolts.

6 - Broken outboard flap carriage spindle, an example for SB 57-A127. 737-3/4/500

On the picture below an example of a broken outboard flap carriage spindle. The inspection for a broken spindle is done in service bulletin 57-1277. Use this picture for information or training purposes only.

It is possible that you can find a small crack (approx 20 mm) on the aft edge of a blended winglet, around the area where the curved trailing edge meets the straight trailing edge. Do not worry, it is cracked sealant (and paint) which was applied to smoothen the transition between the curved and straight trailing edge structure. The sealant cracks because of the loads on the winglet. The crack can occur within several months after installation. See pictures below for more clarity.

After the installation of blended winglets on an aircraft, by means of the APB kit, (not the factory delivered airplanes) you are recommended to schedule the replacement of the engine and apu fuel filter elements after approx 50 flight hours. At the end of the job the APB modification says "close the fuel cells" without any manual reference.

But since you have to work iaw AMM, and if you read the AMM "Fuel Tank Closure" chapter 28-11-00-410-801 , at the end of the Fuel Tank Closure job, it states that after a Major Fuel Tank Repair, you must replace the engine and apu fuel filters after 50 flight hours. This is of course to trap all possible contaminations left in the fuel tanks. If the fueltanks are contaminated too much, the fuel filters can get clogged and subsequently the "fuel filter bypass" warning light will come on. The installation of winglets can be considered as a "major fuel tank repair, or in this case a modification, but the reason behind it is that lots of work (drilling, sealant removal, metal cutting etc) has been done inside the fuel tank. See example pictures below of such a major job.

When you will do the inspection of FWD vertical pressure bulkhead in MWW B STA 663, focus on web between LBL 40 and LBL 45,64 - it is inboard of speedbrake CTRL cables enter to the MWW. You can find crack along chem-milled area as wieved on the pictures. On first picture you can clearly see that the web around crack going to be splitted. Related to B738, FC 14-15000 , FH 37-41000. Check FTD 737NG-FTD-57-09002 for more info. Thanks to Josef, Czech Republic.