Examples of Aircraft Corrosion

Aloha incident
Crevice corrosion of patrol aircraft
El Al Crash in Amsterdam
Electrical connectors of F-16 fighter aircraft

Crevice Corrosion

This example of corrosion damage observed at the CP-140 Aurora maintenance contractor and was kindly supplied by Capt Sylvain Giguère, Research Branch, National Defence Headquarters, Ottawa, Canada.

Popped rivets were found on an external section of that maritime patrol aircraft fuselage. Subsequent inspection revealed corrosion in the bonded area of the skin plates. The cause was believed to be water ingress from a global positioning system (GPS) antenna. It was believed that water penetrated through cracks in the seal surrounding the GPS antenna. Once the water was in, crevice corrosion began and it ultimately led to the loss of the bond between the two portions of the structure. The loss of this bond allowed more water to seep in the structure and generalized the corrosion problem. (top)

F-16 Crashes due Electrical Connectors Corrosion

This particularly vivid example of how a minuscule corrosion problem can have a gigantic impact on the life of a complex system was reported by David H. Horne, who is a NACE Corrosion Specialist and F-16 Fuel System Engineer at the F-16 Structures Branch, Hill AFB, Utah.

The F-16 Fighting Falcon, the first of the United States Air Force multirole fighter aircraft, is the world's most prolific fighter with more than 3,925 delivered. The F-16 aircraft and the F-15 Eagle were the world's first aircraft able to withstand higher G forces than the pilots. The Fighting Falcon entered service in 1979 and is operational with 19 air forces from 76 bases in 20 countries. The F-16 Fighter is a spectacular combat aircraft that has proven its value, but corrosion problems plague its maintainability, safety, and reliability.

One problem discovered by a Kelly AFB Engineer trained in corrosion control was corrosion of tin-plated electrical connector pins mated with gold-plated sockets. Fretting corrosion between these contacts (so subtle that it's not even visible) appears to have been implicated in at least six (6 x $20,000,000 = ONE HUNDRED TWENTY MILLIONS) when their main fuel shutoff valves closed uncommanded.

The main fuel shutoff valve (MFSOV) is the main fuel line shutoff valve just upstream of the single engine. It is necessary to shutoff and make a sure seal so that the strainer two feet down stream can be removed and cleaned and that the engine connection can be disconnected for certain services. It has a cockpit actuating switch so that the pilot could close the valve if some terrible thing happens with the engine.

In addition, the corrosion products of the corroded tin and steel pins provides a potential conductivity path between pins A to B and C to B that may be adequate to drive the MFSOV to close. A corrosion inhibiting lubricant spray, MIL-L-87177A Grade B, has been identified and is used annually as an interim fix. Treatment of electrical connectors with the MIL-L-87177A Grade B was so effective in restoring the conductivity of the tin plated pins and preventing continued corrosion that in a test at one Base the aircraft so treated demonstrated a 16% improved mission capable (MC) rate. In addition, millions of dollars saved by cost avoidances were documented by treating the aircraft and aircraft ground equipment (AGE) connectors. (top)

Other corrosion accidents: Aloha, Bhopal, Carlsbad, Davis-Besse, Guadalajara, EL AL, Erika, F-16, FAC, Flixborough, Gaylord Chemical, Oil pipeline releases, Pitting of aircraft and helicopters, Prudhoe Bay, Silver bridge, Swimming Pool