ATR above FL 250

[DIRRIK]

Hello,

Can somebody explain me why the ceiling of an ATR is artificially limited to FL250?

I know FL 250 being the service ceiling due to the pax drop down O2 mask and maybe it could be a limitation due to max differential pressure.

I ve heared stories of ATRs being ferried above FL250. Did they have special approval?

Dirk

[5150]

They only carried limited O2 for pax supply under JAR-OPS - that's why it's artificially limited. If they went higher they'd have to carry O2 for each seat, below 250 they don't have to.

I know of ferry flights where they've managed to step-climb it to nearer 300, that said, you'll be lucky to get it above that. In the summer we used to struggle getting it above 190!!!

[411A]

There seems to be a general lack of appreciation by some younger pilots about the performance of turbine powered aircraft at higher altitudes.
Perhaps it is thought by some that 'higher is always better' when in actual fact, in many cases, this certainly is not the case.
One might read the accident report of the very stupid performance of the relatively inexperienced pilots of a CRJ operated by Pinnacle Airlines a couple of years ago....could be a rather large wake-up call for younger hot-shot pilots...

[OPEN DES]

@411A

You must be joking.
Were you born aged 50 with 18000 hours in your logbook?

[763 jock]

The important thing is to reach 50 with 18000 hours in your logbook.

[Gooneyone]

Have to agree with 411A. Don't know about the ATR, but the Dash 8 (100/300) are limited to FL250, with the AFM allowing FL260 on ferry flights only. If the AFM states FL250 with pax, why would you want to go above that? If you feel that the limits shown in the AFM can be exceeded at your discretion, you have a problem.

[DIRRIK]

411A and Gooneyone,

You are making assumptions.

I never said that flying higher is always better neither did i say that i feel that limits in the AFM can be exceeded at my own discretion.

I just want to know why the atr is artificially limited at FL250. Is it O2, is it max differential pressure, is it something else?

Grtz
D

[ICING AOA]

I think it s due to differential pressure indeed.
As far as I remember, we can select 30 000 ft maximum on the AFCS ...

[keepitlit]

Its designed for FL250 under normal ops as costs/certification costs increase, all the usual cost driven limits most modern props are 250, the 260 is new to me but its 8 yars since i flew the lovely machine( its a great stepping stone to and airbus, i loved it)

regards

Keepitlit

[vipatr]

I have been told its because the DC generators do not get enough cooling above FL 250.

Is there anybody who can confirm this?

thanks.

[airman13]

ATR-42 is limited to FL 250 due to O2 reasons.They are 12 O2 masks in the cabin ,so one mask for 4 pax...