I should be in Stockholm right now, but instead I'm sitting at home typing this. We had several delays last night and ultimately timed out —i.e., we couldn't make the flight to Stockholm because we would have been on duty more than 16 hours by the time we landed, which is against the rules.
The first big delay was due to the howling winds at Kennedy Airport in New York, gusting up to 51 knots out of the northwest according to the ATIS (Automatic Terminal Information Service, the airport's recorded weather). This limited the usable runways to just 31L and 31R, and that meant delays getting airborne. Kennedy has two other runways, but the gusty winds would have created a direct crosswind.
The ground congestion made it tough for the ramp controllers to get planes in and out of the ramp area, and we waited close to an hour for clearance to push off the gate. After starting an engine, we shut down the APU as usual. As we taxied out, an alert message popped up on our EICAS screen: APU FUEL VAL. Consulting our reference handbook, I found that this message meant that the APU fuel valve wasn't positioned correctly. Checking another onboard manual told me that it wasn't something the crew can deal with on their own. This one would require a trip back to the gate.
Back at the gate, maintenance decided that the APU couldn't be fixed right away, and would have to be "deferred." So we had to use alternative means of starting that first engine (i.e. an external air cart).
A deferred APU is more of a nuisance than anything else, but for trans-oceanic flights it also becomes a safety consideration. We fly under the ETOPS program, which allows a twin-engine plane to be more than 60 minutes of flying time from a diversionary airport. One of the requirements of ETOPS is to have a working APU as a backup power source in case of an engine failure.
Because of this, the folks in operations decided to use our plane for a flight to LAX and swap us to a plane with a working APU. The plane they had in mind was due to land in about a half hour. As you can imagine, it takes time to clean and cater an arriving plane and then move all the baggage from one plane to another, not to mention the people. Our posted departure time of 11:30 pm left us with only 45 minutes of buffer to be off the gate within our duty day.
The whole process took longer than planned, and we didn't make it. When we hit the time limit, we had been on duty for almost seven hours. Add to that the nine-plus hours of duty that lay ahead for the flight and we would exceed 16 hours.
As a footnote to this, you may find it interesting that the 16-hour limit is a Federal regulation for domestic flights, but not for international flights. In other words, we could have volunteered to exceed that limit for our flight to Stockholm, whereas if we knowingly exceeded it for a flight within the U.S. we'd be subject to action by the FAA.
That's the part that has me feeling bad today. We elected not to exceed the limit, and because of this the flight was canceled. Our decision was based on the fact that if something, anything, were to go wrong on that flight, one of the first things we would be asked in an investigation is "Why did you elect to go beyond a 16-hour duty day?" Fatigue has played a role in many accidents, and although we felt okay at 12:25 am (when the flight was canceled), what kind of shape would we be in nine hours later when we had to make the landing in Stockholm?