The deliberate crash of a German airliner with the loss of 150 lives and the disappearance of a Malaysian plane with 239 lives after a mysterious change of course may have had little apparent effect on the confidence of air travellers. They were, after all, unconnected, unprecedented one-off events. But they certainly focused more attention on the state of mind of pilots as an air-safety factor which, unlike human error, cannot be detected by on-board systems.

A case in point is a report last month of a mainland cargo airline pilot who became comatose after a drug overdose. The incident has prompted the Civil Aviation Administration of China to launch a nationwide anti-narcotics campaign among pilots. This is reassuring, but would be more so if there had not been a delay of 10 months before the CAAC was informed of the case last February. The China National Narcotics Control Commission says the pilot took a potentially fatal overdose in Shanghai in April last year, after which he lost his job and was admitted to a community drug recovery centre, where he must attend sessions for three years.

The CAAC has issued a notice declaring that "no effort should be spared" in the prevention of drug use among pilots. The notice said education and management would be enhanced, and aviation officials in charge of drug prohibition would be held accountable. The commission said, rightly, that safety of the public was in the hands of pilots and other public transport employees and the anti-narcotics campaign was urgent. The response and the sentiments are admirable, but bureaucratic inertia and secrecy have done nothing to advance them in the interests of the travelling public. By international standards, there is nothing to hide. The US Federal Aviation Administration has revealed data on the number of private and commercial pilots needing treatment for drug and alcohol abuse and mental illness. Rather, the lack of transparency and accountability has left unanswered questions, such as why it took a year from the pilot's arrest until public disclosure.