Air Nelson - Auto feather

[ViagraDependent]

Heard that one of the new Dash 8's had an uncommanded auto-feather out of Nelson the other day, ended up cooking the engine whilst re-circuiting to land.

Anyone know more on this?

[AerocatS2A]

Heard that one of the new Dash 8's had an uncommanded auto-feather out of Nelson the other day, ended up cooking the engine whilst re-circuiting to land.
Anyone know more on this?

Why did it cook the engine? Did they not shut it down?

[Cloud Cutter]

Again? This happened in AKL just a few weeks back. Prop auto-feathered at 700 feet, resulting in an over-tourque, engine shut-down.

This is not unheard of for the type. Apparently it is the price you pay for having an auto feather that will 'always work' in the real situation.

AS2A, there is no way to prevent a major over-torque if a prop is feathered at takeoff power. I'm surprised the prop doesn't overtake the aircraft as it departs in such a situation.

[Contract Con]

Gday,

I remember Eastern having a few of these, Sunnies had one also.

I cant remember what the cause/fix was now though, too long ago.

Maybe one of the EA/SS boys can shed some light.

Sure to grab your attention though. Re the cooked donk, if you dont get the Power Lever back smartly it over Tq's and Temps reasonably quickly:eek:

I thought Bombardier would have had this sorted by now.

Cheers,

Con:ok:

[mootyman]

Have also heard this happen on a EMB-120, Same situation on take off power.
It ended up being the torque signal conditioner failing which resulted in a zero torque output and auto-feather activating. Very hard to figure out what the actual torque was during the auto feather as the would have been no torque reading.
I also think there was advise coming out from Embraer to ensure that the pilots switched off the auto feather as soon as possible.

[27/09]

I also think there was advise coming out from Embraer to ensure that the pilots switched off the auto feather as soon as possible. Auto feather when you don't have auto feather!!!!

Well I guess switching it off as part of the line up checks would do it then!:hmm:

[Hugh Jarse]

If the situation is an unscheduled feather (ie not initiated by the autofeather system), there would most likely not have been an "Np underspeed cancel" signal sent to the EEC/ECU. This would probably result in an over-torque situation. However, there should be a backup Np underspeed cancel signal sent from the torque gauge, once the torque rises above 120%.

120% is way below that required to kill a PW123E.:E

Having such an event can't bother Bombardier too much. Their recall basically requires no action below plateau height.

That's my understanding. I'm happy to be corrected by you more learned types:O

[nzmarty]

a little birdy told me that the for the first uncommanded afx, the adas download showed a torque value twice the continual max torque, and that the engine was poked.

[Hugh Jarse]

Marty, for the benefit of us that have been flying the type for quite a few years.....What is an adas? I don't know that such a device is fitted to Australian Dashes:confused:

Double Max Continuous on the PW123E is 180%. I don't think so. I find it difficult to understand that not only did the crew experience an unscheduleded feather, but the backup system (torque meter) failed also?

In any instance, the QRH dictates do nothing until plateau height. If the crew followed the QRH, they can hardly be blamed for the backup system failing (which seems to be the feeling I get).

[gaunty]

Precisely.:ok:

Follow the book, DONT second guess it and you will be OK. The days of the hero pilot are pretty much over.
Todays hero professional pilot, you guessed it, follows the book, doesn't second guess it and brings it home without the pax hardly even knowing about it. The design and construction regs are, well......designed that way.:cool: :ok:

My money says that I, the operator and the manufacturer would have reached the pinnacle of our respective professions were we able to walk away from a failure of any one or combination of things without the passengers being aware of it. :D At least that's the target. The pilot and a dog in the cockpit is all we will need.

[ground-run]

It's probably time for some accuracy in this thread. Air Nelson have had one uncommanded autofeather (in Auckland). The engine was not 'cooked' and is still on the wing, but the prop was replaced due to an overtorque (>125%). Suspected cause: either TSCU or Torque Sensor - yet to be confirmed.

[Cloud Cutter]

Hmmm, that's what I thought. Thanks ground-run. I hadn't heard any over-temp or other engine problems resulting either.

Hugh Jarse - ADAS (Altair Data Acquisition System) is an engine trend monitoring system.

Do the Air Nelson Q300s have them?

[Uncle Chop Chop]

On the same tune but hitting a different note...I was on tower freq the day of the auckland incident and congrats to the crew. Not even a hint of stress on the radio. Shot lads:ok:

[Cloud Cutter]

Yip, I agree. If you weren't expecting it you may have just thought Air Nelson had adopted the Mount Cook, one engine taxiing routine. It seemed well handled by all concerned.

[nzmarty]

thanks for that CC - i'm not sure if the dash has adas as such, but it does have a full downloadable fdr. nelson just doesn't have the software to analyse it. i've seen the spreadsheet for the said overtorque, and it was pretty impressive.

i'm sure the dash's got some way of telling on the pilots for those flap/gear/temp exceedances.....

[Hugh Jarse]

i'm sure the dash's got some way of telling on the pilots for those flap/gear/temp exceedances.....

Marty,
We have such devices on our A/C: QAR's.:oh: For exceedances(?) outside of certain parameters, one gets "FOQA'd":uhoh:

However, a torque exceedance such as which may have occured during an unscheduled feather would not result in a FOQA, as it would reasonably be expected to occur (infact is noted in the recall of the QRH).

The company isn't always out to ping you :} :8

[nzmarty]

not always......

on uncommanded incidents maybe not, but extending flap when you're a bit quick will be frowned upon (where i'm from anyway) as it just make more work for us black handers........