Sudden stall for no apparent reason

Was flying an A320 out of Gerona, flying 340. Over the Pyrenees I was on autopilot, climbing through 240 for 330 with the autothrottle set at M0.7. This might have been a bit high but I was experimenting and wanted to get to the Spanish/French border quickly. At this point, over the Pyrenees, my airspeed started to fall rapidly. Pushed the nose forward to increase speed but as soon as I tried to level out the speed dropped again. Eventually crashed.

 

I've recently installed France scenery and I wondered if the transition from the default Spain scenery to the addon France scenery would, somehow, cause this to happen. Any ideas?

Gotta ask the simple question first! Pitot Heat on? MACH .70 may be a tad too much to ask. What was the climb rate?

2000 ft/min

 

No pitot heat, but flown this aircraft for long periods without resorting to looking for pitot heat. Also, the drop in spedd was sudden and fairly rapid.

Top Gun,

 

Just tried the same situation with Pitot Heat switched on. Made no difference. But happened at the same geographical location. Next, going to remove the France scenery and see what that does.

I would decrease climb rate to 1200-1500 fpm.

Your description sounds a lot like trying to force the aircraft into performance that it doesn't have available at that altitude. You might remember that non-turbocharged engines lose power with increasing altitude. This includes jet engines. As a result, aircraft rarely can maintain a sea level high rate of climb as they get up there. Since the aircraft has less power at altitude, especially above 18,000 where the engines probably have less than half their sea level power.

 

Trying to maintain almost cruise speed at that altitude while still at a high rate of climb is also a conflict in priorities. So mrzippy's suggestion of a lower climb rate is a very good choice, except I'd initially drop it to 1,000 fpm and work from there. I doubt the scenery has anything to do with it.

Total agreement, Larry! You da man....sometimes! ;)

You're both right, again. Reduced to 1,000 fpm and M0.6 and bingo, sweet as a nut. Thank you.

 

I don't usually fly with those parameters but I was trying to get to the Spanish/French border quickly, to test my France scenery.

Good to hear! Keep 'em flying! :D

You're both right, again. Reduced to 1,000 fpm and M0.6 and bingo, sweet as a nut. Thank you.

 

I don't usually fly with those parameters but I was trying to get to the Spanish/French border quickly, to test my France scenery.

 

Mach is a relative speed: `Mach` number is the ratio of an object's speed in a given medium to the speed of sound in that medium.

So your relative speed my have no bearing on your actual air speed:

https://en.wikipedia.org/wiki/Mach_number

You would not use Mach speed for any low-airspeed aircraft, only KIAS...

.

Note how the difference reduces as the altitude increases?

You're both right, again. Reduced to 1,000 fpm and M0.6 and bingo, sweet as a nut. Thank you.

 

I don't usually fly with those parameters but I was trying to get to the Spanish/French border quickly, to test my France scenery.

 

When you get in a hurry like that, you can use slew mode to get there quickly, if you like.