IGN in Emer Descent
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Joined: Jan 2012
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From: Swindon
IGN in Emer Descent
Why is there the requirement for switching on the Ignition in an Emergency Descent?
Obviously airmanship wise it's never going to be a bad idea but anyone with more than that to add?
Cheers
CC1
Obviously airmanship wise it's never going to be a bad idea but anyone with more than that to add?
Cheers
CC1
Joined: Jan 2001
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From: Around the world.
For example, on a CFM56, it is detrimental to select ignition in almost any case according to CFM.... reason being it can detect a flame out more quickly than each spark on continuous; and if the spark is required due flameout there is a higher voltage available thus a stronger spark available in a fraction of a second due to not continually discharching the capacitors in the ignitor box. At the airline I work at it is SOP to select ignition on the CFMs in Emer descent... no idea why.
Joined: Jan 2008
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From: All at sea
Probably because you are at idle thrust and don't know what conditions you may encounter on the way down. With all the chaos around, you may not be thinking (or have time to think) 'icing', so it seems like a good idea, regardless of type.
Joined: Jun 2006
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From: Australia
ust follow QRH.
Otherwise we end up with a whole other virtual manual of opinions to muddy the waters. If you really think you have a great idea get your tech or training dept to ask the manufacturer.
Otherwise we end up with a whole other virtual manual of opinions to muddy the waters. If you really think you have a great idea get your tech or training dept to ask the manufacturer.
Joined: Mar 2006
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From: expat
Ahem...
missed the point of the original post. Apologies.
Agree with MachE, though alot of modern engines have auto this and that so not as much a consideration as in the past.
missed the point of the original post. Apologies.
Agree with MachE, though alot of modern engines have auto this and that so not as much a consideration as in the past.
Last edited by HPSOV L; 13th June 2012 at 13:59.
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From: Home soon
For example, on a CFM56, it is detrimental to select ignition in almost any case according to CFM.... reason being it can detect a flame out more quickly than each spark on continuous; and if the spark is required due flameout there is a higher voltage available thus a stronger spark available in a fraction of a second due to not continually discharching the capacitors in the ignitor box
Thanks.
Joined: Jan 2001
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From: Around the world.
I'm trying to find it for you, I had it in a presentation somewhere I am sure but no joy so far, I thought it was in a CFM ops seminar but can't see a reference now (unless I'm completely loosing the plot and thinking of the V2500). Any one else know?
Looking through the CFM seminar, if it detects any decel greater than expected on normal schedule (among other things) it will immediately engage dual ignition anyway.
Looking through the CFM seminar, if it detects any decel greater than expected on normal schedule (among other things) it will immediately engage dual ignition anyway.
Last edited by tom775257; 13th June 2012 at 16:45.
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From: Romania
@Tom
Autoignition is available only on 737 - NG ( CFM 56 -7).
On the classics CFM 56 -3 you don't have this feature ; in order to keep the commonality between CL and NG you have to put them on continous.
Hope it helps
Autoignition is available only on 737 - NG ( CFM 56 -7).
On the classics CFM 56 -3 you don't have this feature ; in order to keep the commonality between CL and NG you have to put them on continous.
Hope it helps
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From: UK
Jeeesus!
If the QRH says so, fekkin do it!
What on earth is so hard to understand about that?
I know we descend at idle with no ignitors on every day, but are some of you some kind of self-appointed galactic test pilot who knows more about this than the manufacturer's test pilots do? Which TP school do you come from - do tell...
If such superior Test Pilot please speak up.
If not, kindly shut up and let the rest of us Professional pilots follow the checklist. Gobshyte fools.
If the QRH says so, fekkin do it!
What on earth is so hard to understand about that?
I know we descend at idle with no ignitors on every day, but are some of you some kind of self-appointed galactic test pilot who knows more about this than the manufacturer's test pilots do? Which TP school do you come from - do tell...
If such superior Test Pilot please speak up.
If not, kindly shut up and let the rest of us Professional pilots follow the checklist. Gobshyte fools.
Joined: Mar 2002
Posts: 4,569
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From: Florida
Agree with QRH discussions but.... the question was posed as to why the procedure? That I interpret is a legitimate question to underrstand the reasoning behind it, rather than to challenge that it is wise to follow or not.
Somewhere in the vitrolic above are some excellent points that may or may not apply to the machine that you fly.
Somewhere in the vitrolic above are some excellent points that may or may not apply to the machine that you fly.
Joined: Apr 2010
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From: Home soon
Jeeesus!
If the QRH says so, fekkin do it!
What on earth is so hard to understand about that?
I know we descend at idle with no ignitors on every day, but are some of you some kind of self-appointed galactic test pilot who knows more about this than the manufacturer's test pilots do? Which TP school do you come from - do tell...
If such superior Test Pilot please speak up.
If not, kindly shut up and let the rest of us Professional pilots follow the checklist. Gobshyte fools.
If the QRH says so, fekkin do it!
What on earth is so hard to understand about that?
I know we descend at idle with no ignitors on every day, but are some of you some kind of self-appointed galactic test pilot who knows more about this than the manufacturer's test pilots do? Which TP school do you come from - do tell...
If such superior Test Pilot please speak up.
If not, kindly shut up and let the rest of us Professional pilots follow the checklist. Gobshyte fools.
I suggest you start running and see a specialist
Joined: Aug 2008
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From: Betwixt and between
Why is there the requirement for switching on the Ignition in an Emergency Descent? Obviously airmanship wise it's never going to be a bad idea but anyone with more than that to add?
Given the possible slow reaction by the crew due to workload and those potential changes in the outside environment, I think it should be judged an essential safety measure.
Thread Starter
Joined: Jan 2012
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From: Swindon
unstable retards
Thank you to those who offered considered opinions to a question posed out of curiosity. Nothing more sinister than that I'm afraid.
To those frustrated,aggressive,intellectually challenged losers, you are a disgrace.
If ever there was a thread that exposed the effects of the proliferation of the pilot license to the Neanderthals, this is it.
I'm just starting out in this profession and hope the Captains I will have to fly with will be from a more robust selection process.
CC1 is now retiring.
To those frustrated,aggressive,intellectually challenged losers, you are a disgrace.
If ever there was a thread that exposed the effects of the proliferation of the pilot license to the Neanderthals, this is it.
I'm just starting out in this profession and hope the Captains I will have to fly with will be from a more robust selection process.
CC1 is now retiring.
