A320 Automatic start

[Flyman35]

I see many pilots putting their hand on the Master switch while the Engine is starting when I asked why they said to shut down the engine if something happens, I remember when I was in Airbus during simulator training the instructor told me do not put your hand on the switch during start because you may do something wrong for the FADEC, so any ideas?

[toby320]

there is nothing bad to mantain your hand on the switch, in fact in case of a electrical failure you need to switch the mater off, even in automatic start so...

[ROSCO328]

I would agree with your instructor keep your hands off! Full Authority Digital Engine Control :ok:

[320p]

Hello.
We have been told that beyond 50% N2, FADEC would not do automatic shutdown in case of hot start or high EGT.I couldn't confirm this from the FCOM.(IAE engine)
Any inputs on FADEC's not shuting down engine beyoind 50% N2?

[clarkieboy]

Hi,
FADEC has the capability to cut off the fuel all the way to N2 idle speed on an automatic start.(V2500) The Master switch can directly shut off fuel, and has priority over FADEC in doing so. Hope that helps!

Cheers

[longobard]

tailpipe fire? not memory item, but nice to know!

[Stone_cold]

FCOM 1.70.80 page 4 "Automatic Start"

[Henry VIII]

tailpipe fire? not memory item, but nice to know! I do agree :ok:

[potkettleblack]

If someone inadvertently walks near your engine during startup and the ground engineer is shouting to cut it is the FADEC going to shut it down for you? In our outfit we "guard" the master switches.

[320p]

Hi,
Thanks for FCOM Reference.Among other details it states:
runs an abort sequence if a start aborts on the ground when N2<50%.
-closes the HP valve
-closes the start valve
-turns off the ignition
-cranks the engine
So the question remains,when N2>50%( and upto idle)would FADEC still abort in case of hot start,stall or some other engine malfunction.

[toby320]

So the question remains,when N2>50%( and upto idle)would FADEC still abort in case of hot start,stall or some other engine malfunction. Today 15:18
simply answer....yes in case of any abnormal during eng start folow the ECAM and DO NOT INTERRUPT the fadec protective actions by non requested actions on start panel

[320p]

Thanks toby,
I do understand part about following ECAM,but could you correlate with what is mentioned in the FCOM about FADEC and auto abort on ground with N2 <50%.It does not say about auto abort till idle is reached.

[troubleshooter74]

The FADEC start protection is active up to 50% N2. This is indicated by a highlighted grey background on the N2 indication. As soon as this grey background has disappeared it is up to you.

[Zippy Monster]

But given that you cannot see the engines from the A320 flight deck, and that your eyes are on the E/WD monitoring the engine start-up, how are you going to know there are ground crew wandering in front of the engines?

No captain, including the senior TREs that I have flown with in my airline, keep their hands on the start switch during the start sequence nor have ever mentioned it. There is nothing in our SOPs about doing it either.

Having your hand on the master switch may cause you to make an instinctive reaction to shut the engine down when it would do no good, and as others have said, would interrupt the FADEC protections. Not touching the switch might just mean you take time to think about it for a second rather than instinctively yanking the switch off.

If a call comes from the ground that someone is wandering perilously close to an engine, then you could always move your hand back to the switch again... and if they're fatally close, then given the time it would take the engine to spool down, it would probably make no difference whether your hand is on the switch or not.

[Dream Land]

Having my hand on the master is something I don't do and don't feel is necessary, also, here's a good example why you want to let the FADEC finish the auto-start process before securing the master, not too long ago, one of our crews immediately turned off the master during a start fault.

A second attempt to start the engine produced a flame out of the front of the engine, nearly as big as the flame out the back of the engine, the engine which was new, had to be replaced. :ugh:

D.L.

[320p]

Hello troubleshooter74,
"The FADEC start protection is active up to 50% N2. This is indicated by a highlighted grey background on the N2 indication. As soon as this grey background has disappeared it is up to you".
The grey background on N2 disappears once the engine stabilises at idle which is around 60% N2.
Hence ,I wanted to know if FADEC provides start protection between 50% N2 and idling RPM?
Thanks!

[Jimmy Do Little]

Keep your hand on the switch - FADEC doesn't detect everything. Like groundcrew wandering near the engine intake.
Very good point! Nonetheless, let the FADEC do its job during those "detected" faults.

[toby320]

ok, the fadec will provide protection during automatic start until reach the 50% of N2 in real world even more like 3or 4% up, but above of that parameter the fadec asume no malfunctions can be a fact to abort the start

[Bruce Waddington]

Hi All,

If memory serves me correctly,

On the A320 family with the CFM engines you must intervene in the event of a "Overspeed Protection Fault" or a loss of AC power (ie APU failure during first engine start).

So, hand on the Master switch, but no other intervention required.

On the A340/A330 fleet with CFMs or Trents, no intervention required at all, so hands off the Master Switch.

regards,

Bruce Waddington

[Bula]

I challenge anyone who are using the "what if an engineer walks in front" argument to close their eyes, look away and spend more then a second finding both masters.... At the end of the day your motor memory will find the location of the switch and know exactly where they are.

If the n2 >50%, you are correct that the start will not abort. Don't get an abort confused with a FADEC Automatic recover, designed to mitigate hot and hung starts.

<50% N2, the FADEC will abort start if required. Have a look at your EGT after 50% n2. There is only a very small increase in EGT ,relative to the start prior up to that point, and reduces quite quickly there after.

Using internal schedules the FADEC should know prior to 50% N2 whether the engine will overheat. If >50% n2 the engine exceed redline on a normal clean start, there is an issue with the engine and needs to be check by engineering.

Dont worry about the overtemp.