Aircraft throughout Europe may have to make emergency landings as a result of the residual effects of the volcanic ash, according to Leeds University lecturer, Stephen Wright.
The threat comes from the aircraft air-conditioning systems which could fail over the coming months as planes begin to ‘hoover up’ the additional ash in the atmosphere.
‘These systems pressurise the cabin and warm the internal temperature using heat from the aircraft engines,’ explained Wright. ‘When they become clogged, they can overheat, forcing the pilot to shut the system down and make an unscheduled landing.’
Air conditioning systems are usually checked every 18 months due to the high levels of dirt they collect which can block the heat exchangers. Wright said that aircraft air con units will now be faced with a cumulative build-up of ash as well dirt which could ground the planes.
‘These units are buried in various parts of the aircraft,’ he said. ‘To get to them for maintenance requires several men and a serious number of hours. Not many people are going to have a complete unit, my worry is that if you get enough planes up there you’re not going to have enough spares.’
Wright added that overheating could be serious as in most cases the air conditioning units are fitted underneath the central fuel tank. While these systems have built-in safety controls, in theory they could catch on fire and ignite the fuel onboard.
Responding to the concerns, the UK Civil Aviation Authority confirmed Wright’s claims however said there is unlikely to be an immediate impact.
‘It is correct to suggest that the presence of ash in the atmosphere could marginally reduce the life of air conditioning system,’ it said. ‘In any case, any degradation of the air conditioning system performance can be detected and, although a descent to a lower operating level may be required, the aircraft can still continue with its intended flight.’