Flight delaying passing 10,000 feet
 

Last year I took a flight on one of BA's mid-haul B767s which experienced a mechanical fault. It halted the climb before reaching 10,000 feet and flew for around an hour at that altitude (or actually slightly lower, at 7,000 feet) before reaching Brussels (from LHR) then announcing the fault and returning to LHR to land before standing on the runway for a few mins while the plane was inspected, then returned to gate. It was an interesting flight! The flight was re-arranged for the following day and that was delayed too, due a passenger fainting while we were taxing to the runway!

When I fly now, I keep an eye on the altitude (when it's displayed) during take-off. Frequently it appears a plane will climb straight up to cruising altitude. Other times, the climb will be have one or more "pauses", presumably where air traffic control are regulating where and when the climb can occur. However, on a couple of occasions (including another medium haul flight from LHR yesterday) we climbed as far as 6,000 feet, but then remained at that altitude for some time. Yesterday, we flew at 6,000 feet for 20 minutes. For any pilots (or people with more flight knowledge than me) what would be the reason for this? Is it likely to be air traffic control directing this, or is it possible/likely its due to the plane crew requesting a pause to confirm the equipment is ready to proceed above 10,000 feet? Yesterday we flew south of London, passed Chartwell by ~50km then entered our climb, with the B777 pushing us up rapidly. Given one of the LHR holding areas is over/near Chartwell I assume air traffic control regulation is most likely in this case? In the case of plane crew initiating the delay in the climb, what is the procedure they follow?

Thanks in advance to anyone sharing their knowledge on my rather verbose queries!

John

It just varies depending largely on the departure procedure being used, planned route, weather, and air traffic (and sometimes other factors like the aircraft's relative performance capabilities or airspace restrictions for various reasons). It has nothing to do with any requirement to pause and check equipment before reaching a certain altitude.

Yes. :-:

Almost always ATC based.

Airplanes fly more efficiently at higher altitudes. (I.e, less fuel, costs less)

There's no reason a crew would choose to fly lower if they didn't have to.

I see this once a week or so we get a strip printing out with a final altitude of 090 or 100 and a message saying PRESS INOP.

Certainly agree with, which is why my gut says they were purposely flying lower. If they just took off, they would have been fully loaded with fuel. Unless they were high enough and in area where it was allowed, they wouldn’t be able to dump fuel to shed mass. So in order to land safely and not risk brake overheating/failure, they may have chosen to burn fuel instead. And if you’re going to be flying around in a circle burning fuel, you might as well find an “inefficient” altitude to get the job done faster. :p