Repair and maintenance

Case Study: Repair of aircraft wing flap and slat tracks

L1011 titanium alloy slat track repaired by TIG welding and HVOF coating

Repair of slat track by TIG welding and HVOF coating

Flap and slat tracks contribute to the smooth and safe operation of aircraft wing area during take off and landing procedures. Over an extended service period, grooves are worn in the main bearing surface by abrasive and adhesive wear by stainless steel bearings. Tracks have to be replaced (or repaired) before flap or slat mobility is impaired. TWI's experience of working with aircraft repair and maintenance company, Marshall Aerospace, indicates that during a typical aircraft life (in excess of 20 years), it is expected that on average each slat and flap tracks will need to be replaced (or repaired) on two occasions. Airlines can now opt to have replacement parts (cost $2000 to $5000) or repaired parts ($1000).

TWI has worked with Marshall Aerospace of Cambridge to develop a procedure using modern techniques and processes for the repair of titanium alloy slat and flap tracks for the Lockheed L1011 (Tristar) aircraft. The repair is a two step procedure:

Restoration of component dimensions using a TIG weld overlay with a consumable of matching (or similar) composition.
Coating the repaired track with tungsten carbide to provide improved wear resistance using an HVOF spraying process.

TWI has approval to carry out this repair procedure.

Surface Engineering at TWI