I was most disappointed to read of the planned action to impose fines on airlines for arriving early or late at Changi Airport (Changi to penalise airlines that don't watch the clock; March 19).

While I understand that early or late arrivals put a strain on the air navigation system, the authorities may not be fully aware of the many reasons behind these, which are often beyond the control of pilots or airlines.

For example, a recent flight I took from Frankfurt was delayed by 40 minutes because the ice on the aircraft wings had to be removed before departure. If this happens often, leading to the airline being classified as being "habitually late", is it still fair to penalise the airline?

Another factor that influences flight times is the change in seasonal upper winds.

These vary between summer and winter, as well through a particular season.

Thus, published flight schedules can only broadly represent airlines' expected flight times during a season, and can still change depending on the winds.

More importantly, airline pilots must not be pressured, subtly or otherwise, to ensure on-time arrivals. The captain's task is and must be to fly his airplane safely.

If an airline or pilot is aware that the flight time will be significantly shorter than the published flight schedule, should they delay departure to ensure the plane arrives on time at its destination?

Similarly, if the flight time is longer, would the airline now direct its pilots to fly faster so as to arrive at the destination on time?

The authorities have indicated that the operational details will be made known to airlines soon.

Our aviation authority is well known for its consultative approach as it strives to make Changi Airport the world's best airport.

It must realise that airlines or pilots do not wish to deliberately delay their flights as there are other important ramifications or considerations. There must be a better way to deal with such issues.

Ng Kok Seong

Vice-President (Technical)

Air Line Pilots Association Singapore