Melted Engines

[Oakum_Boy]

Do they have the number of that truck driving school. Truckmasters was it?

 

[Oakum_Boy]

The melted engine is the one that relit at altitude when they followed the memory item and selected continuous ignition to ON. They are very lucky that both didn't re-light. They got the other engine started later and it functioned properly and got them safely to the ground.

I didn't follow that. Maintaining sufficient airflow (not selecting ignition) would keep the spools turning, enabling a restart at lower altitude.

Ignition is used initially to "relight" a flameout.


A seized engine with no airflow, ignition, and fuel cock open....

Perhaps that's what you were referring to.

 

[sinkrate]

At those altitudes if you are close to an aerodynamic stall the engines will compressor stall. For most AC the memory item for a compressor stall is to retard the thrust lever to recover normal airflow thru the engine. Leaving the thrust lever pushed up is guaranteed to over temp the engine if it does not flame out. The CRJ procedure is different and I've never known why.

A generic high altitude approach to stall recovery goes something like this

-thrust levers to idle to save the engines
-break the stall
-are the engines still lit? - if yes drive on - if not once you reach an altitude low enough attempt to relight the engine.

The CRJ is one of many thrust limited AC. Get slow at altitude in one of these and you are going to pay one way or the other. For some reason CRJ pilots don't seem to learn this. Most operators of the AC have had incidents and continue to have incidents with this. Perhaps it is because of their low altitude straight wing background. Haven't heard of a D-9 doing this in a long time.

 

[Flying Illini]

I didn't follow that. Maintaining sufficient airflow (not selecting ignition) would keep the spools turning, enabling a restart at lower altitude.

Ignition is used initially to "relight" a flameout.


A seized engine with no airflow, ignition, and fuel cock open....

Perhaps that's what you were referring to.

The memory item in the CRJ-100/200 for a dual engine flameout is:
Continuous Ignition....ON
Airspeed....240kts Minimum
That's it and it's not dependent upon altitude even though the engine relight envelope doesn't begin until 21,000'.

I can't tell you why airspeed is second and ignition is first, but it is. Maybe Bombardier will change that now.

A stall recovery involves max thrust which its likely the thrust levers were near the firewall anyway.

The engines may or may not have compressor stalled. They could have just flamed out from the interrupted airflow. I'm guessing that the engines flamed out and the stick *pusher* occurred nearly simultaneously. I could see the scenario unfolding where a stall recovery was then initiated my pushing the T/L's to the stops and when there was no response glancing at the engine instruments then reaching up and selecting the Cont. Ign to ON.

Again, they were very lucky that only one engine relit.

 

[sinkrate]

The memory item in the CRJ-100/200 for a dual engine flameout is:
Continuous Ignition....ON
Airspeed....240kts Minimum
That's it and it's not dependent upon altitude even though the engine relight envelope doesn't begin until 21,000'.

I can't tell you why airspeed is second and ignition is first, but it is. Maybe Bombardier will change that now.

A stall recovery involves max thrust which its likely the thrust levers were near the firewall anyway.

The engines may or may not have compressor stalled. They could have just flamed out from the interrupted airflow. I'm guessing that the engines flamed out and the stick *pusher* occurred nearly simultaneously. I could see the scenario unfolding where a stall recovery was then initiated my pushing the T/L's to the stops and when there was no response glancing at the engine instruments then reaching up and selecting the Cont. Ign to ON.

Again, they were very lucky that only one engine relit.

The dual engine flame out procedure assumes you started in the normal flight envelope. In this case they didn't. Early in the life of the CL-600 they had a problem with engines flaming out above FL400.

In the CRJ the only time the auto ignition comes on is for high angle of attack. When it does come on there is no manual override to turn it off.

As the compressor stalls reverse airflow develops. The engine starts to spool down so the ECU adds fuel to maintain fan speed. The turbine cools so the ITT is no longer an accurate reflection of the temp in the burner, etc. Since the crew cannot select the ignition off the fuel in the burner continues to burn as long as there is air. The only thing the crew can do to save the engine is to bring the thrust levers to idle to get them out of the ECU governing range and into manual HMU control.

Remember - the only reason you select max thrust in a stall recovery is to minimize the altitude loss. In a number of approach to stall instances max thrust will not help you avoid a stall, you are going to sacrifice altitude.

 

[Flying Illini]

The dual engine flame out procedure assumes you started in the normal flight envelope. In this case they didn't. Early in the life of the CL-600 they had a problem with engines flaming out above FL400.

In the CRJ the only time the auto ignition comes on is for high angle of attack. When it does come on there is no manual override to turn it off.

As the compressor stalls reverse airflow develops. The engine starts to spool down so the ECU adds fuel to maintain fan speed. The turbine cools so the ITT is no longer an accurate reflection of the temp in the burner, etc. Since the crew cannot select the ignition off the fuel in the burner continues to burn as long as there is air. The only thing the crew can do to save the engine is to bring the thrust levers to idle to get them out of the ECU governing range and into manual HMU control.

Remember - the only reason you select max thrust in a stall recovery is to minimize the altitude loss. In a number of approach to stall instances max thrust will not help you avoid a stall, you are going to sacrifice altitude.

I understand all of that. My previous post was nothing more that explaining the memory item and what I think the likely course of action by the crew was. Obviously the cont. ign. came on with the stall and it can't be over-rode but as soon as the stall was broken they would have had to engage the ignition again.

High altitude stall recovery is something that needs to be trained far better than it currently is. At least now the stall recovery does not emphasize zero altitude loss like it used to.

 

[Oakum_Boy]

I think many don't realize that it takes significant nose-over to recover from a high-alt stall/low speed situation. The main issues is WHY is this occurring. Just like the Colgan thing. Stall recovery bungled, but WHY are crews not paying attention.

What is possibly going on that crews aren't aware that they are getting slow. I see a lot of pilots with poor airspeed control on approach and in cruise. The main question I'd like to ask them is:

What in the name of.......are you looking at?!! The PFD is so concise and compact, it shouldn't be difficult to miss, unless you're just poorly disciplined, trained, or lazy. Or your scan just plain sucks. I suspect a combination of the above.

Get it together guys, or we're gonna be out of business due to Risk Management yanking our flying.

 

[OPECJet]

What happened to thrust levers: cutoff, continuous ignition on? Been that way for every jet I've flown unless there was no continuous ignition selector. Then it's thrust levers: cutoff.

Seems to me they're assuming you're melting an engine and trying to give you a chance at a relight when you're in the envelope.

 

[bigshooter107]

Anyone got a link to a news article? Was this really PSA?

 

[sinkrate]

High altitude stall recovery is something that needs to be trained far better than it currently is. At least now the stall recovery does not emphasize zero altitude loss like it used to.

Agreed. It needs to be type specific too.