This evening, I decided to do a long haul from LEMD, and here we go again, the same incident happened on the same aircraft, the A350.
I also did a long haul a few days ago from EGLL where the same thing happened.
For some reason, it seems like the aircraft suddenly looses speed and then it’s altitude of course, in total, I’ve received 3 violations due to this issue.
For the people that will tell me I should’ve kept an eye out, I was asleep at 5AM trusting the autopilot, and then tonight, the same thing happens, bringing me an extra 3 violations to the account, you shall now view the 2 replays I have of this issue.
You were going 1800 vs up to 36000 and that’s when you started to lose speed. The issue was your VS which resulted in a stall as you got higher. The 350 is a big plane and requires attention to vertical speed when climbing and descending. In some ways it behaves like an MD11.
It is advised to not leave it unattended until you reach cruising altitude.
Did you replay my long haul file from EGLL? I had reached cruising altitude and everything was doing fine for an approximate 4 hours, I had reached FL360, seems like it was fine for those 4 hours.
Was flying EGLL-LEMD earlier and not exactly away from my iPad, it was on my desk getting regularly checked.
The AP just randomly went to -13kFPM for a few seconds then tried to correct itself back to the alt set in the AP. Was most peculiar… will try get a replay uploaded tomorrow. I’ve never had AP on IF act like that with me before.
I’ve flown 3 A350 flights without A/P problems (currently on my 4th). I am not able to watch the videos but:
Stalling is an issue of low speed, and high V/S at inappropriate altitudes. As @Chris_S is saying, you might be going too high too fast, and/or you might be too high too early. Autopilot will disengage if you force the plane to do things that are difficult to do (for example cruising at FL500 will probably disengage autopilot)
At certain altitudes, you have to have the right V/S, and the right speed, and if you haven’t set a correct speed on A/P, you need to have the right amount of throttle. I bet you might experience those similar problems in a 787 but I don’t know.
I suspect a combination of inappopriate V/S, speed, and altitude. Again, in my case, no problems. It would be better to screen record exactly what you’re doing when you’re taking off and climbing, the saved replays don’t always show this precisely.
Let the devs create a tutorial on flying the A350 and I’m sure you will fly the A350 like me without any problems:)
My case might want you to say “that’s wasting fuel” but with the A350 I pack like 3-5 hours extra of fuel and I ascend with 2300-2500vs and above 10K I put speed to around 324 and I can make it up to 40K. I can’t explain what happened on the EGLL flight.