Recall the aphorism, written in humor, that, "You can have it fast, cheap or right. Pick two." This saying was not conjured based on an aircraft maintenance problem, but it does raise the question about whether specific cases and related aphorisms can be conjured. The answer is an unequivocal affirmative. Digest the following pithy epithets and the investigative reports that prompted them:
Oil's well that ends well, but when things take a nasty turn, convene a missing panel of inquiry. The case involved a British Airways B757 on its first flight following a 26-day maintenance check from London's Heathrow, as recounted by the Air Accidents Investigation Branch (AAIB) report:
"Shortly after takeoff on a scheduled passenger flight ... a hot oil smell, that had been present in the cockpit on engine startup, returned. The flight crew donned oxygen masks and immediately diverted to London Gatwick Airport. ... When the autopilot was disconnected, a large amount of manual left roll control was needed to prevent the aircraft from turning to the right. The aircraft landed safely ... The investigation determined that the accident had been caused by maintenance errors that had culminated in the failure to reinstall two access panels ... on the right-hand outboard flap, and incorrect procedures being used to service engine oils. ... The following causal factors were identified: The tasks of refitting the panels to the right wing and correctly certifying the work carried out were not performed to the required airworthiness standard ... [and] The maintenance planning and task instructions, relating to oil servicing on the Boeing 757 fleet, were inappropiate ..."
Outward demeanor versus "inner bearing." This incident involved an Australian Air Express B727 freighter in which a main landing gear wheel was found cracked through the central hub. The Australian Transportation Safety Board reports:
"The investigation established that the wheel had previously undergone a repair of the inner bearing recess, wherein a bushing was installed into an oversize machined hub bore. ... The wheel manufacturer was aware of the possibility of fatigue cracking from improperly machined hubs and had introduced a documented procedure for the non-destructive inspection of bushing-repaired hubs. ... There was no indication that the subject wheel had been inspected ... following the implementation of the bushing repair."
Nothing is fool-proof to the sufficiently talented fool. The case involves a Pakistan International Airlines B777 at Manchester airport, as documented in the AAIB incident report:
"Whilst the aircraft was taxiing, following an otherwise uneventful landing at Manchester, flames were seen around the wheels of the left main landing gear. ... The investigation determined that the cause of the fire, established as being in the No. 10 main landing gear wheel, most likely resulted from the maintenance practice used when cleaning the wheel heat shields. It was likely that these had been immersed in an unapproved and flammable solvent, which allowed the ceramic fiber insulation material contained within to become contaminated. The fire occurred on the second landing after the wheel had been fitted to the aircraft, when the brake pack temperature was likely to have been higher than on the previous landing."
The covers of this manual are too far apart. A Piper Turbo Arrow crashed on a highway shortly after takeoff because of an engine failure. The engine had had a cylinder replaced just before take off. According to the National Transportation Safety Board (NSTB):
"[The investigator asked the mechanic] how did he determine it was serviceable and he explained he assumed it was. ... When asked about the manual requirements to install the cylinders, [the mechanic] stated he could install a cylinder from memory because he had done it so many times. `I could even install it blind folded,' [he] said. [He] stated he did not have a maintenance manual during installation."
Many more such accounts can be produced, but these are sufficient to generate one final and discerning sagacity: "Keep looking around; there's always something you've missed."
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