Does this happen in a real 777?

Question

Okay i have a question for the pilots here.
In FlightGear flight simulator, I'm flying this 777-200LR,
at 35,000ft, mach 0.85, autopilot on LNAV, and autothrottle engaged.
The aircraft starts to climb, goes up to say 35,400 (speed drops), then starts to go down again say to 34,600 (speed increases), this cycle is repeating for like the last one hour!
Does this happen in a real 777? or is this a bug with the game?
thanks.

Answer 1

It's a bug in your game. Throw away that trashy thing. The best flight simulators that I have seen for FSX come from PMDG. They are expensive, but no other models come close. I happen to know a programmer at PMDG.



In the real world, the two most common issues with autopilots (one of which has happened to me inflight), are intermittent disengagements (not including strong turbulence or mountain waves like Zaphod mentions), or failure to engage. The causes range from power supply failures to invalid commands being sent to the flight control computers. Neither issue is usually serious in terms of safety, but they do increase the workload on the pilots.

Answer 2

No, though you are just playing a game so obviously the programmers probably don't know what's possible or not possible in a real aircraft....and even if they did they can't account for everything cause that would be a nightmare trying to program in

Answer 3

Would not vary by that much in a ral plane unless there are unusual weather conditions

Answer 4

No, not unless the autopilot is out of spec or unless there are strong mountain wave conditions.