A320 Eng Start Fault - Engine Egt Overlimit

[Skipping Classes]

Gentlemen,

Yesterday we had an engine 2 start fault with the following ECAM:

ENG 2 START FAULT
ENG 2 EGT OVERLIMIT

We called the maintenance and after quite a long telephone call we found out that the T5 was 417 degrees C during the engine start (aids - fadec 2 a - troubleshooting etc) and that the hard limit is 423 degrees C. So we could do a manual start and go, however, according to the maintenance if the T5 temperature was above 423 the aircraft would be grounded for a boroscope inspection.

When I read FCOM3 Abnormal Procedures regarding this particular ECAM warning I do not see a clear requirement for any investigation/maintenance action after EGT OVERLIMIT during start. In fact it says that you should/could try a manual start right after the starter has cooled down.

In this situation, do I assume that a more severe ECAM warning would be displayed if the T5 has exceeded 423 degrees C?

Or are you required to call maintenance every time you see START FAULT EGT OVERLIMIT during the start? (Obviously the T5 limit could be different for different engines)

This problem has caused us a major delay with disembarking the passengers etc and a number of flights being late in turn while in the end all we had to do is a manual start if we knew the T5 limit beforehand.

Please share your opinion.

SC

[TyroPicard]

CFM or IAE? They differ slightly.
TP

[fantom]

Maybe it was the RATE of rise (rather than the ultimate temp achieved) which led to the ECAM warning.

We humble humans know nothing.

f

[lomapaseo]

Could it be that there are two types of limitations

one is to abort the operation and try it another way if the EGT rises above a set level in a specific operation (hung start)

Yet another limit applies under all operations and that is the hard EGT limit, since it implies that thermal damage may have occurred (usually up front in the turbine) and not back where the EGT is measured.

So the crew follows the operating procedure (limitations) and the maintenance guys follow the maintenance limitation section.

[JETZ Tech]

From the figures given I am assuming your A/C has IAE V2500 Engines on it, as figures for CFM engines are different.
Are you doing Auto -Starts as part of your normal SOP? As in Auto the FADEC sysytem should perform cerftain tasks before shutting down.
FADEC will provide the same level of warnings for any Temp over the Hard Limits as you call them. So you should call Maint whenever this occurs. They have to verify the Temp reached and for how long it was at that Temp. This will dictate the required inspections.i.e visiual or Boroscope.
Your company's AMM will have to be consultaed for requirements.

[N1 Vibes]

SC

EGT OVERLIMIT - there is no other "more severe ECAM" warning. This message requires investigation by the enigneer to establish time and temp over AMM limit, which appears to have happened in your case. As for the 423 degC, on our V2500-A5 a/c the start limit is 635 degC. Suspect you may be using brand B engine on your a/c?

Some engine FADEC and a/c logic has an "impending" exceedance limit. So the red-box appears on the flight deck screen, but the actual temp is not exceeded, the red box should clear when the EGT winds down, i.e. the box does not remain as a hard indication. Hope this helps.

Brgd's

N1 Vibes

[gilsonrh]

Someone answer my question about no egt limit during start A320???

[Kuchan]

CFM56-5B
AUTOMATIC START: The maximum EGT during start sequence is 725ºC.
MANUAL START: The maximum EGT during start sequence is 725ºC.
---
EGT OVERLIMIT OR STALL FAULT IN AUTOMATIC MODE:-
In case of detected stall or EGT overlimit, the FADEC monitoring and the flight crew actions are identical.

FIRST ATTEMPT
When a stall or an EGT overlimit is detected, an aural warning sounds, the MASTER CAUTION and the engine FAULT lights come on. An ECAM message appears.
The FADEC shuts off the fuel and ventilates the engine (crank time : 7 seconds).

SECOND ATTEMPT
The FADEC reduces the fuel flow and attempts a second start.
Fuel schedule reduction : 7 percent.
If the abnormality re-occurs a second time, the FADEC shuts off the fuel and ventilates the engine (crank time : 7 seconds).

THIRD ATTEMPT
The FADEC reduces the fuel flow and attempts a third start.
Fuel schedule reduction : 7 percent (a total of 14 percent).
If the abnormality occurs a third time, the FADEC shuts off the fuel and ventilates the engine (crank time : 7 seconds).

FOURTH ATTEMPT
After 7 seconds, the FADEC reduces the fuel flow again and attempts a fourth start.
Fuel schedule reduction : 7 percent (a total of 21 percent).

If the abnormality occurs a fourth time, the FADEC aborts the start.

SUMMARY
* 4 start attempts :
- a normal start
- plus 3 additional attempts.

-----------------
V2500
AUTOMATIC START:
Max EGT:- starting, for up to 2 minutes, 590°C.
- Transient 635°C.

MANUAL START: Max EGT:
- Starting, for up to 2 minutes, 590 degrees C.
- Transient 635 degrees C.

EGT OVERLIMIT AND STALL FAULT IN AUTOMATIC MODE In case of detected stall or EGT overlimit, the FADEC auto start control or the flight crew actions are identical.

When a stall or an EGT overlimit is detected, an aural warning sounds, the MASTER CAUT and the engine FAULT light come on. An ECAM message appears.
The FADEC shuts off the fuel and ventilates the engine.
After the auto cranking, the FADEC aborts the start sequence.
Then the MASTER lever must be set to OFF.

[capt. solipsist]

kuchan,

good stuff :ok:

may i have the reference?

[tcasblue]

CFM56-5B
AUTOMATIC START: The maximum EGT during start sequence is 725ºC.
MANUAL START: The maximum EGT during start sequence is 725ºC.
---
EGT OVERLIMIT OR STALL FAULT IN AUTOMATIC MODE:-
In case of detected stall or EGT overlimit, the FADEC monitoring and the flight crew actions are identical.

FIRST ATTEMPT
When a stall or an EGT overlimit is detected, an aural warning sounds, the MASTER CAUTION and the engine FAULT lights come on. An ECAM message appears.
The FADEC shuts off the fuel and ventilates the engine (crank time : 7 seconds).

SECOND ATTEMPT
The FADEC reduces the fuel flow and attempts a second start.
Fuel schedule reduction : 7 percent.
If the abnormality re-occurs a second time, the FADEC shuts off the fuel and ventilates the engine (crank time : 7 seconds).

THIRD ATTEMPT
The FADEC reduces the fuel flow and attempts a third start.
Fuel schedule reduction : 7 percent (a total of 14 percent).
If the abnormality occurs a third time, the FADEC shuts off the fuel and ventilates the engine (crank time : 7 seconds).

FOURTH ATTEMPT
After 7 seconds, the FADEC reduces the fuel flow again and attempts a fourth start.
Fuel schedule reduction : 7 percent (a total of 21 percent).

If the abnormality occurs a fourth time, the FADEC aborts the start.

SUMMARY
* 4 start attempts :
- a normal start
- plus 3 additional attempts.



Thanks, Is there any Crank message during the 7 second crank periods? Why no crank after the last attempt?

[krismiler]

Or are you required to call maintenance every time you see START FAULT EGT OVERLIMIT during the start?

My airline, yes. Anything other than ignition fault requires a return to stand and a techlog entry.

[Fursty Ferret]

Is there any Crank message during the 7 second crank periods?

There is during the crank on IAE engines following an aborted start.

[The Banjo]

What a load of rubbish:
With an auto start (2500) the EGT overlimit ECAM simply states that the autostart was aborted because of a POTENTIAL overtemp start. That is what the computers are for: to PREVENT an overtemp!! If it did actually overtemp ->635 degrees, there will be a red marker on the EGT display then engineering required.
If there is no red marker which should be the case then no parameter has been exceeded, engineering is not required (subject to own company procedures) and another start can be attempted. Usually a dry crank followed by a manual start which gives better start margins.

A wise man once said to turn a mountain into a mole hill, not the other way around.....

[tcasblue]

There is during the crank on IAE engines following an aborted start.

What about a crank message for CFM aircraft?