Ask the Captain: Why the 15-hour rule could cause a delay

— -- Question: I was on a trip from New York JFK to Jacksonville. The flight was taxiing to the runway when the pilot came on the intercom and said, "I am at my 15 hour a day max. Due to federal regulations we are returning to the gate." Now every time I fly I wonder if I will make it to my destination or be stopping halfway because the pilot's time is up. So why didn't they figure this out BEFORE we left the gate?

— submitted by reader Mike in Florida

Answer: This is a very good question. Pilots want to complete their scheduled flights. There are requirements for the maximum hours on duty during a duty period. In your example, once the pilot would have reached 15 hours before reaching JAX, they would have exceeded the maximum allowable hours.

If you look at the completion rate for airlines, you will find that cancellations are very rare. This should relieve your concern about whether you will make it to your destination. Events causing cancelation, including crew duty time, occur very infrequently.

If the pilots could know how long the taxi time would have been, they might have been able to determine if there was a need to cancel before departing the gate. For example, if the taxi time to the departure runway were 20 minutes, there might not have been a crew duty time issue. However, if traffic congestion caused the taxi time to grow to two hours, this could exceed the maximum hours. Until the crew taxied away from the gate, there is not a good way to determine the taxi time. Often a crew will coordinate with the dispatch office to attempt to learn of conditions that could lead to exceeding the crew duty day.

Q: How do pilots and flight crews adjust to time zone changes, especially on long flights, (the mainland of the U.S. to Hawaii for example), and are they given extra time for rest before flying again?

— Stu Wright, Orangeburg, S.C.

A: Managing fatigue on long flights can be challenging. One of the ways of coping is if you are only going to be in a city for a short time, try to minimize the effect by eating and sleeping to your body clock time. This is not always possible but often can help.

One of the most important ways to deal with fatigue is to begin the trip well-rested. Fatigue is greater when a sleep deficit builds up. By starting well-rested, the sleep deficit is lessened.

The FAA has recently revised duty time and rest requirements for flight crew members. This will give more opportunity for greater rest between flights.

Adjusting to time changes is part of many flight crewmembers' workdays. There are many different ways of coping. Each person finds what works best for him or her. Careful management of food and sleep times is a common mitigation.

John Cox is a retired airline captain with U.S. Airways and runs his own aviation safety consulting company, Safety Operating Systems.