Tired pilots 'are risking safety'
Over-tired pilots who fall asleep on duty are putting passenger safety at risk, MPs have been told.
Rob Hunter of the British Airline Pilots' Association said fatigue levels should be measured before flights to help alleviate the problem.
But "intense" competition by airlines to raise profits made this less likely, the transport committee heard.
Transport Minister Theresa Villiers said overall safety would improve as a result of changes to be made soon.
The committee is looking at the number of hours flight crews should be working.
The MPs heard that 43% of pilots said they had fallen asleep in the cockpit, based on a survey of 500 members of the British Airline Pilots' Association (BAPA).
Mr Hunter, the union's head of safety, said this was likely to lead to more accidents and that more should be done to gauge the problem.
He told the committee: "We need an appropriate reporting procedure. People fear that if they report fatigue they will be subject to a disciplinary process. Their concern is that they will be effectively writing the evidence for their own prosecution...
"We commonly receive letters that deal with cases where pilots feel that the process that they then get embroiled in is more fatiguing that the duty itself. It becomes a better option to put up with a bit of fatigue rather then report it."
The committee heard that, where there were only two pilots on a flight, they both had to remain on duty for the duration of the journey.
Mr Hunter said: "Sometimes airlines endorse a napping policy, where each pilot has a sleep... It can be effective...(but) one pilot who is (meant to be) awake can fall asleep."
But airlines often did not prioritise the issue of fatigue, he said, telling MPs: "They are very survival-driven. It's intensively competitive... as consumers and passengers we get a sense of the intense competitiveness in the airline industry."
During the hearing there was dispute over how easy it was to measure the level of fatigue among pilots.
Mr Hunter said the scientific method was reliable but added that airlines were "really quite woolly" in their implementation.
Representatives of carriers said this was not the case.
Tim Price, the regulation manager for flight operations at British Airways, said any measurement also did not take into account the activities of pilots in their spare time on their level of fatigue.
The UK system of dealing with fatigue - setting out hours to be worked, and the length of breaks in between - is to be replaced with a European-wide system.
Critics argue this will lead to a "levelling-down" of standards, but supporters say it means UK citizens who use flights operated by companies based elsewhere in the EU will get better safety.
Ms Villiers said moving to a Europe-wide system of safety regulation "would undoubtedly bring up the standards to a broadly equivalent level to that in the UK".
She added: "That will be a significant gain for British passengers when they get on planes."