Airbus- All Engines Flame Out (fuel remaining) Checklist

[7478]

hey guys

If you lose all engines (with fuel remaining) in the cruise at FL400, what would you initial target speed be?
the all engines flame out (fuel remaining) C/L says 300 knots for optimal relight. Would you consider green dot speed to begin with?

shed some lights. thanks
:)

[qualitycontrol]

All depends whether range is a factor - if you are in the middle of nowhere then green dot buys you the most time to prep for forced landing etc - if you are over the top of central europe you have a bit more room to go for relights etc.

Hope that helps.

[Henry VIII]

And terrain profile too. Crossing mountain I would use green dot till terrain clearance is assured.

[Thunderbug]

Caution with going straight back to Green dot. We've just had a revision from Airbus put into our manuals. It states:

NOTE- In the case of an "ENG DUAL FAILURE" during high power operations (i.e. climb, cruise) it is mandatory to fly at or above the optimum relight speed in order to prevent engine core lock.

Our checklist (A320 IAE) says 280kts Optimum relight speed.

I believe this stems from feedback from the Pinnacle Airlines CRJ crash

Pinnacle Airlines Flight 3701 (http://en.wikipedia.org/wiki/Pinnacle_Airlines_Flight_3701)

T'Bug

[yoyonow]

The logic of the 'new' checklist is pretty straight forward:

- Engines flame out, you want to relight them asap or all you are doing is gliding to the crash site.
- Therefore you must get enough air through the engines to start them.
- Above apu availability height (varies) then windmill is the only option.
- Therefore 300 knots.
- With apu available then assisted start is available so back to green dot to extend glide time.

Exemptions would obviously exist to this standard strategy in the event of high terrain.

[lomapaseo]

I'm with Yoyonow:ok:

However I also considered that the original question was posed as if they couldn't be relit (don't ask me why).

Then this quote below puzzled me

NOTE- In the case of an "ENG DUAL FAILURE" during high power operations (i.e. climb, cruise) it is mandatory to fly at or above the optimum relight speed in order to prevent engine core lock.

I am quite surprised that a manufacturer (Airbus) would use a word like "mandatory". That is a word reserved for the authorities or somebody like an employer who holds authority over you. Thus I suspect that the quote is an interpretation outside of Airbus.

[Pro Spin]

Hi All

I would say first thing is to always double-check Fuel SD page by pressing and holding the Fuel button on ECAM switching panel so it appears on upper ECAM screen (as total fuel on board indications on EWD will be lost until FAC 1reset). This ensures you use the right checklist! (Fuel remaining OR No Fuel Remaining).

As a pilot who flies A320s with both engine types, the IAE engines have an optimum re-light speed of 280kts, whereas the CFM engines have a higher re-light speed of 300kts.

With CFM engines, this means that with a dual engine failure in a cruise at high altitude, the optimum relight speed may be quite a way above MMO, and a progressive increase in speed towards 300kts during the descent may be required to avoid exceeding MMO.

Pro Spin.

[Microburst2002]

I cannot recall where i learnt about the engine core lock problem.

I think the best course of action, at that high altitude, with fuel ON (thanks for the FUEL PAGE tip!) would be to pitch down, achieve 300 kt (or 280 IAE) without exceeding MMO of course, and trying to relight, as the procedure estates.
Even more so if you can have an engine core lock!

[aristoclis]

I would say first thing is to always double-check Fuel SD page by pressing and holding the Fuel button on ECAM switching panel so it appears on upper ECAM screen (as total fuel on board indications on EWD will be lost until FAC 1reset). This ensures you use the right checklist! (Fuel remaining OR No Fuel Remaining).

Pro Spin,

Could you please specify where you found this information? I could not find any relation between FAC and EWD total fuel on board.

Thanks.

[A-3TWENTY]

I would at first try to find/reach a field to go, then try not to land as a glider.

[bobrun]

With CFM engines, this means that with a dual engine failure in a cruise at high altitude, the optimum relight speed may be quite a way above MMO, and a progressive increase in speed towards 300kts during the descent may be required to avoid exceeding MMO.

Would like to add that, at that high of an altitude, you'll be above the max guaranteed relight altitude anyway. Once at or below that altitude, flying at the optimum relight speed won't be a problem.

[jhurditch]

Can someone please explain the idea of core lock to me. From what I understand it means the engine components change size and do no longer fit as designed. Is this from a cooling or heating? After a flame out at high altitude are you in a situation where core lock could occur immediatley? Why do we maintain optimum relight speed? If the metals where going to change size wouldnt it happen regardless of speed.

This question may be stupid but this symptom is new to me..

Thanks

[sb_sfo]

Google is your friend. Wikipedia too.
Core lock - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Core_lock)

[jhurditch]

Thanks mate, I have looked at it. The wiki article was where most of my unanswered questions arrose from.

[Thunderbug]

From the NTSB Pinnacle Airlines report


1.18.2 Core Lock
During the investigation of this accident, the Safety Board learned that GE CF34-1 and CF34-3 engines had a history of failing to rotate during in-flight restart attempts on airplanes undergoing production acceptance flight testing at Bombardier. The manufacturers referred to this condition as “core lock.” Bombardier first identified this problem in 1983 during Challenger certification tests, and GE attributed the problem to interference contact at an air seal in the high pressure turbine.
The CF34 high pressure turbine air seals are designed to control cooling and
balance airflow. The seals include teeth on the rotating components that grind operating grooves into abradable surfaces on the stationary components. The efficiency of these seals significantly affects engine performance, so the seals are designed to operate with minimal clearances.
Bombardier added a procedure that screened for core lock to the production
acceptance flight tests for its airplanes powered by CF34-1 and CF34-3 engines. At the time of the accident, this screening procedure was as follows:
1. Climb to 31,000 feet.
2. Retard the test engine throttle to idle and stabilize for 5 minutes.85
3. Shut down the test engine.
4. Descend at 190 knots.
5. Slow the aircraft until N2 is reduced to 0 percent.
6. At 8 1/2 minutes from shutdown, push over to 320 knots.
7. If N2 is 0 rpm at 21,000 feet, the engine is declared to be core locked.
Engines that are found to be core locked are reworked using an in-flight “grind-in” procedure that was designed to remove seal material at the interference location. Engines that undergo grind-in rework are then rescreened for core lock. The grind-in procedure is as follows:
1. ATS cross-bleed start.
2. Ascend to 31,000 feet.
3. Repeat core lock screening procedure but descend at an airspeed of
about 240 knots to establish 4 percent N2.
4. Maintain 4 percent N2 for at least 8 1/2 minutes.
5. Confirm that no core lock exists by repeating screening procedure.
As testimony during the Safety Board’s June 2005 public hearing on the Pinnacle Airlines accident indicated, neither Bombardier nor GE considered core lock to be a safety-of-flight issue. The manufacturers claimed that engines that passed the screening procedure, with or without grind-in rework, would not core lock as long as the 240-knot airspeed was maintained.
Bombardier’s core lock screening procedure requires a cool-down period before
engine shutdown to stabilize internal temperatures and clearances. However, this procedure does not produce the more severe thermal distress associated with the high power, high altitude flameouts that were experienced during the accident flight. As stated in the Safety Board’s November 20, 2006, safety recommendation letter to the FAA the successful demonstration of Bombardier’s flight test procedure might not ensure that an engine will
not experience core lock if the core is allowed to stop rotating after a high power, highaltitude flameout. In its letter, the Board noted that the No. 1 accident engine had successfully passed the screening procedure during initial production acceptance testing.The Board further stated that the successful demonstration of Bombardier’s flight test procedure might not ensure that slowing the airplane to an airspeed of 170 to 190 knots is
sufficient to maintain core rotation during an attempted APU-assisted restart


T'Bug

[7478]

thanks for the input. in fact, the engine core lock thing is brand new to me.

let's say a suitable ERA is 200nm away when both engines flame out. we're over the Phillippines at FL400 and no significant terrain exists. Now,having confirmed that tonnes of fuel are in tanks, would you still go as per QRH to 300 knots straight away?

we may descend at roughly 1500-2500 fpm until we reach the APU assited start altitude of FL250. is attempting a windmill start straight away at 300 knots giving you a higher chance of survival than trying to glide as far as possible before an APU start is available?

i'm a new junior crew member on the bus. The check capt and a line capt have split approaches towards the scenario.

[Thunderbug]

The scenario in the Pinnacle accident is that they did not keep the engines rotating. They were not going fast enough for a windmill start and the core locked which meant that once they had reached an altitude at which they could use an APU assist - It was too late. The engines were never going to start.

In my view you have to lose the height and keep those engines in a workable state. You must though consider why your engines flamed out. In the Pinnacle incident it was due to mucking around at high altitude that caused the flame out. The engines would have been able to function once back in a suitable environment.

If the engines have flamed out to bird impact or something that may have damaged them - It is a judgement call. If you think they are damaged beyond useable, then go for green dot, trade height for distance. If you think they are useable then try to get then going again.

T'Bug :ok:

[lomapaseo]

we may descend at roughly 1500-2500 fpm until we reach the APU assited start altitude of FL250. is attempting a windmill start straight away at 300 knots giving you a higher chance of survival than trying to glide as far as possible before an APU start is available?



Some food for thought

The re-light envelop is not only a function of windmill speed but also of pressure altitude, so you need to decrease altitude from 40k at a rate that gives you the longest time with enough speed at a low enough altitude.

Now as far as stretching the glide. That is a much lower priority unless you know that there will be a suitable landing place at the end of the glide.

decisions decisions ......