Rules alone will never prevent pilot weariness. That can only be done by a combination of sound guidelines and systems to prevent their abuse

The day will never come when airlines and flightcrew agree on flightcrew duty time (FCDT) limitation regulations, so it has been no surprise that European pilots have vociferously opposed the approval of a standardised European Union law on the subject that attempts to take into account arguments by both parties. But it is not necessary for them to agree for the rules to do the job they were intended to do - to reduce to an acceptably low level the risk of an accident in which pilot fatigue is a factor.

For this to be true, however, it is absolutely essential for the airlines to operate rosters that respect the spirit of the FCDT laws, not merely the letter of the law. Nearly 20 years ago, the UK Civil Aviation Authority, which operates one of the world's most mature FCDT regulatory systems, made precisely that point when introducing some revisions to its existing guidelines. The CAA said that creating absolutely watertight, abuse-proof rules - but flexible enough to allow commercial airlines to operate viably - is impossible because there are so many variables. The rules attempt to set a safe maximum duty time considering the number of sectors flown; the time of day or night the duty starts; the number of time zones to be crossed; the time of day or night the crew has to try to get some sleep, including the pilot's "body clock" relative to the local time; the minimum time between going off duty and reporting for duty the next duty, taking into account getting to and from a place of rest, eating, sleeping, eating again and returning to work; the maximum number of duty hours for the day/week/month and year; and whether these are worked out on a calendar basis or a 24h rolling basis.

In all aviation regulations the objective is to manage risk, because eliminating it entirely is not possible. The FCDT rules are not intended to protect pilots from being tired after an honest day's work, but to prevent a build-up of debilitating fatigue, which renders pilots more liable to make errors in judgement and decision-making, and robs them of physical self-awareness. Rules that enable an airline to operate viably, not only in terms of getting a reasonable amount of productive time per month out of the pilots, but also of providing crews - when they need it - with the option of a duty time extension to complete the day's task after unforeseen technical or operational delay - will always be liable to abuse by unscrupulous airlines. Cramming a week's maximum duty time into three days can be done if airlines fly to legal daily maxima three days in a row, and in one of them the duty extension option is used without operational cause.

There are systems in place for countering abuse, however. National aviation authorities are there to prevent it, and pilot unions can also be a vital safeguard. In most countries where crews normally operate safe hours, the limits have traditionally been set not by law, but by agreement between the pilot unions and their employers. But by the nature of things, FCDT abuse has to start before it can be detected or reported, so there is a risk. There needs to be a confidential reporting system to enable whistleblowers to alert a lax national authority to regulatory abuse before it becomes systemic. Some pilots are unlucky enough to operate in a country where the aviation establishment - meaning the authority and the airline - are effectively a unit, and fatigue is not recognised as a danger. In some of these countries whistleblowing can be career suicide.

European pilots, demonstrating last week against what they see as a set of new, politically determined regulations, say they want rules based on science. The trouble is that, in the USA, where a great deal of research has been done on fatigue, the conclusions remain as debatable as the definitions of the words "tired" or "fatigued", so US pilots remain unhappy with their rules and it looks unlikely they will get change in the short term. In Australia, a long-term, real-time study is monitoring the effects of fatigue on line pilots by measuring their performance (Flight International, 18-24 March 2003), but even when that study yields up its derived data, the results will remain a tool for creating a basically sound set of rules and recognising abuse when it occurs, not for creating regulations which are simultaneously abuse-proof and yet flexible enough to enable commercial operators to continue in business.

Keeping dangerous pilot fatigue at bay is the combined job of the national authorities, airlines, pilot unions and, finally, individual pilots in command. Rules alone can never work.

Source: Flight International