The FAA is being challenged to stop allowing ancient aircraft to remain in commercial service without special inspections

Old is an imprecise - or at least subjective - description of people or aeroplanes. The US National Transportation Safety Board is struggling valiantly to persuade the Federal Aviation Administration to extend the scope of the various programmes it has that could be generically grouped under the heading of "ageing aircraft" schemes.

As the NTSB's chairman Mark Rosenker has just said at an ageing aircraft seminar, the passage of time is not the only guide to the increasing risks that people think of as being associated with age. The aircraft involved in the accident that woke up the FAA - and the whole world to the dangers of ageing or high-use aircraft was a 19-year-old Boeing 737-200. Nineteen years for a turbine aircraft of that generation might be considered mature, but not old. It was an Aloha Airlines 737 that had operated the second highest number of cycles in the global 737 fleet at the time - the year 1988. Another factor was Hawaii's environment: the air is humid and salty, which created a more rapid advance of corrosion than normal in the airframe. Aloha, with its island-hopping network, also owned the number one highest-cycle 737, but as the roof literally blew off the forward fuselage of the number two aircraft at nearly 30,000ft (9,150m), the former was undergoing extensive anti-corrosion maintenance that involved re-skinning. Amazingly, the badly damaged aircraft's crew were able to land the 737 safely, and the only loss of life was to one of the cabin crew who was not strapped in when the catastrophic failure occurred.

That accident galvanised the FAA into action. It drew regulators and manufacturers from all over the world and led an international exercise that defined most of the maintenance procedures and regulations that govern the operation and structural inspection of old and high-cycle aircraft today.

In 1996 the TWA 747-100 that suffered an explosion of its centre-wing fuel tank led the FAA to specify additional inspection and replacement requirements for electrical wiring and systems. That brought the USA more or less to where it is today, but Rosenker makes it clear the NTSB wants the FAA to go further. He has said he thinks it is unacceptable for the travelling public to face the massive differences in risk inherent in travelling in seriously old aircraft compared with younger or lower cycle airframes.

Rosenker has homed in on the very oldest aircraft in US commercial service today, but goes beyond passenger types signalling that professional flightcrews should not be required to fly high-risk aircraft like ancient Lockheed C-130As and other types used in the firefighting role. The most recent passenger aircraft example of what he worries about is the December 2005 crash of a Grumman Mallard seaplane. Fatigue in the wingspar led to catastrophic failure and the death of 20 people.

It is clear what really unsettles Rosenker. The rules don't require supplemental inspections of active commercial transport aircraft built before 1958 on the grounds - according to the FAA - that there are so few of them (about 80) and the cost involved would put the services they perform at risk.

Actually, that's a lot of aeroplanes carrying a lot of people. In 2002, Russia decided to revoke permanently the operating certification for the 17 remaining Ilyushin Il-18 four-engined turboprop airliners following an accident, even though none of them was as old as the 1947-built Mallard that crashed. Nigeria is considering grounding all commercial transport aircraft beyond a certain age on the premise that it cannot guarantee their structural and electrical safety when maintenance becomes a much more extensive - and expensive - job.

This need not be the death knell for vintage show aircraft, warbirds and the like. But if aircraft are money-earning passenger-carrying types, or firefighting aircraft, or former Vietnam "Hueys" being used for logging operations, their operators should pay the cost of supplemental inspections as the price for staying in service. If they are warbirds that only carry the crew, the pilots know well the risks of flying them and have chosen to do so. That is different. Like all adventure sports, the participant accepts the risk. But operators should not be able to take passengers' money for flying in really old aircraft unless they are subjected to strip-down inspection and critical part replacement, nor hire professional pilots to fly such veteran aircraft in utility roles unless they are similarly checked out.

Source: Flight International