Challenger Landing Gear Hidden Corrosion

June 2011

Challenger landing gear requires a detailed inspection at 60 months for the 600 and 601 and 96-months for the 604 and 605. It must then undergo a 120-month restoration for the 600 and 601 and 192 month for the 604/605.

The reason for these inspections is to check for cracks, wear and corrosion. Years of water, dirt, salt air, fluid and various other electrolytes have taken their toll. The gear is very susceptible to corrosion and even though steps may have been taken to lessen the effects, some corrosion still forms.

Corrosion is normally found throughout the gear but can often be repaired using standard repair schemes available in the CMM or through engineering concessions. Sometimes, however, the corrosion has exceeded the limits of those repair tolerances.

Some of the more severe corrosion found during these inspections is detailed in the following photographs.

	MLG Trailing Link Axle Bore corrosion found in 35% of the restorations. Engineering Concession can be requested.
	MLG Side Strut Pin Corrosion on OD radius found in 50% of restorations. No repair schemes exist.
	MLG Hinge Pin Corrosion on the ID mating with brake line swivels found in 70% of the restorations. CMM details a repair scheme for the area.
	MLG Oleo Pin Corrosion on the ID found in 65% of the overhauls. No repair schemes exist for this area.
	MLG Oleo Cylinder ID corrosion found in 50% of the restorations. Engineering concession can be requested.
	NLG Main Fitting Corrosion under steering sleeve found in 50% of restorations. Engineering concessions can be requested.
	NLG Plunger Tube Corrosion, lower band mating with axle found on 75% of restorations. CMM details a repair scheme for the area.
	NLG Axle Barrel Corrosion mating with plunger tube found on 75% of restorations. CMM details a repair scheme for the area.
	NLG Steering Cuff Corrosion in the ID Bore found in 60% of restorations. CMM details a repair scheme for the area.
	NLG Axle Transverse Bore Corrosion found on 50% of the restorations. CMM details a repair scheme for the area.
	NLG Steering Rack Tooth damage going to caster mode found during 90% of restorations. No repair scheme available.
	MLG Side Strut Rod End Bearing bore corrosion found in 85% of the restorations. CMM details a repair scheme for the area.
	MLG Side Strut Bearing bore corrosion found in 85% of the restorations. CMM details a repair scheme for the area.