A320 APU Fire Test with APU already running
Thread Starter
Joined: Feb 2018
Posts: 36
Likes: 0
From: Earth
A320 APU Fire Test with APU already running
Hi all
Is there anything somewhere in the books that specifically prohibits this during Cockpit Preparation?
The APU fire test does not shut down the APU on ground and as far as I am able to interpret the procedures, crew has to perform the APU fire test even if it is left running by previous crew/maintenance.
What's your take on this?
Regards
What's y
Is there anything somewhere in the books that specifically prohibits this during Cockpit Preparation?
The APU fire test does not shut down the APU on ground and as far as I am able to interpret the procedures, crew has to perform the APU fire test even if it is left running by previous crew/maintenance.
What's your take on this?
Regards
What's y
Only half a speed-brake
Joined: Apr 2003
Posts: 4,459
Likes: 136
From: Commuting not home
Asked several times over the years, and all the answers are already provided above.
Once a a line engineer told me the only issue is with a in-depth MX / warning system troubleshooting procedure , when a C/B gets pulled.. The system logic would err on the conservative side and fire the squib.
Just a story.
Once a a line engineer told me the only issue is with a in-depth MX / warning system troubleshooting procedure , when a C/B gets pulled.. The system logic would err on the conservative side and fire the squib.
Just a story.
Joined: Jul 2006
Posts: 1,100
Likes: 111
From: Somewhere over the rainbow
Maybe I'm missing something but I don't understand why you need to perform the APU fire test. If you arrive at the aircraft and APU is already running, it means the maintenance has turned it on and has done the APU fire test already.
In the company I work for, we only do that test if the cockpit crew arrives at the aircraft and APU is not running.
In the company I work for, we only do that test if the cockpit crew arrives at the aircraft and APU is not running.
Joined: Nov 2010
Posts: 1,167
Likes: 180
From: USA
Maybe I'm missing something but I don't understand why you need to perform the APU fire test. If you arrive at the aircraft and APU is already running, it means the maintenance has turned it on and has done the APU fire test already.
In the company I work for, we only do that test if the cockpit crew arrives at the aircraft and APU is not running.
In the company I work for, we only do that test if the cockpit crew arrives at the aircraft and APU is not running.
Our SOP is that when you pick up an aircraft, you test the APU fire detection, running or not. It has to be tested every day and maybe it was left running from the previous evening and the test is required again (we operate 24/7).
Only half a speed-brake
Joined: Apr 2003
Posts: 4,459
Likes: 136
From: Commuting not home
Doing less is inherently safer, in this respect reduced amount (of unnecessary) decision making is better.
If the FCOM suggestions work unaltered, it is easier just to follow them - same as Hans'. For us new crew = new start, irrespective of what has been left running.
pinteam: it is my personal belief the reason for the BAT check split between PM and PF during the cockpit prep is to cover for one of the guys actually not doing the job at all. On what is a survival-critical system in case of a larger failure inside the electrics. Good SOP would have such "recovery" features embedded.
That's where your company's way - whilst perfectly reasonable under the assumed state of things - falls short of the (slightly ignorant) FCOM regime, me thinks.
If the FCOM suggestions work unaltered, it is easier just to follow them - same as Hans'. For us new crew = new start, irrespective of what has been left running.
pinteam: it is my personal belief the reason for the BAT check split between PM and PF during the cockpit prep is to cover for one of the guys actually not doing the job at all. On what is a survival-critical system in case of a larger failure inside the electrics. Good SOP would have such "recovery" features embedded.
That's where your company's way - whilst perfectly reasonable under the assumed state of things - falls short of the (slightly ignorant) FCOM regime, me thinks.
Last edited by FlightDetent; 15th January 2019 at 20:21.
Thread Starter
Joined: Feb 2018
Posts: 36
Likes: 0
From: Earth
Thanks guys. Interesting feedback.
Regardless of individual company SOPs, it is clear now that there is nothing in the Airbus procedures prohibiting it.
@pineteam
It often happens that an aircraft arrives within a few minutes of the next departure; in such cases, the previous crew leaves the APU running to save APU start cycles. Therefore, we cannot assume whether they left it ON or the engineering switched it ON. Even if its engineering that did it, it's still a part of FCOM procedure and a change of crew definitely necessitates a fire test.
The point of asking this question was due to the fact that I was recently confronted by a Captain who asked me to prove where its written. I pointed out there's nothing prohibiting it, and with back to back flights with crew change, sometimes the APU remains ON continuously.
Apparently some people have their own interpretations of the FCOM. Not everything is mentioned nor can be mentioned explicitly for every situation. Thats how it works.
Regardless of individual company SOPs, it is clear now that there is nothing in the Airbus procedures prohibiting it.
@pineteam
It often happens that an aircraft arrives within a few minutes of the next departure; in such cases, the previous crew leaves the APU running to save APU start cycles. Therefore, we cannot assume whether they left it ON or the engineering switched it ON. Even if its engineering that did it, it's still a part of FCOM procedure and a change of crew definitely necessitates a fire test.
The point of asking this question was due to the fact that I was recently confronted by a Captain who asked me to prove where its written. I pointed out there's nothing prohibiting it, and with back to back flights with crew change, sometimes the APU remains ON continuously.
Apparently some people have their own interpretations of the FCOM. Not everything is mentioned nor can be mentioned explicitly for every situation. Thats how it works.
Joined: Jun 2001
Posts: 3,780
Likes: 0
From: Surrounded by aluminum, and the great outdoors
do you fly the entire 320 family of aircraft? if so you might want to research what happens if you perform the APU fire test in other models, and see if performing the test while the APU is running has a negative effect on those models...one possible reason for you company' SOP......in any event, the SOP should be sufficient reason for you to not perform the test....no?
Joined: Mar 2006
Posts: 2,633
Likes: 137
From: USA
do you fly the entire 320 family of aircraft? if so you might want to research what happens if you perform the APU fire test in other models, and see if performing the test while the APU is running has a negative effect on those models...one possible reason for you company' SOP......in any event, the SOP should be sufficient reason for you to not perform the test....no?
Joined: Jun 2007
Posts: 3,443
Likes: 39
From: Wanderlust
Is there anything that forbids APU test when it's running? The answer is NO. Rather if you are not sure if the test was done you should do it.
Below from FCOM PRO NORM SOP
Below from FCOM PRO NORM SOP
FIRE
APU FIRE pb-sw.......................................................... .........................................IN and GUARDED
AGENT lights ............................................................ ............................................................ ..... OUT
If the APU is already running, ensure that the following check has already been completed. If not,
perform it.
APU FIRE TEST pb.......................................................... ......................................................PRESS
Check :
‐ APU FIRE warning on ECAM + CRC + MASTER WARN light (if AC Power available).
‐ APU FIRE pb-sw lighted red.
‐ SQUIB light and DISCH light on
APU FIRE pb-sw.......................................................... .........................................IN and GUARDED
AGENT lights ............................................................ ............................................................ ..... OUT
If the APU is already running, ensure that the following check has already been completed. If not,
perform it.
APU FIRE TEST pb.......................................................... ......................................................PRESS
Check :
‐ APU FIRE warning on ECAM + CRC + MASTER WARN light (if AC Power available).
‐ APU FIRE pb-sw lighted red.
‐ SQUIB light and DISCH light on
Last edited by vilas; 17th January 2019 at 06:47.
Joined: Apr 2011
Posts: 487
Likes: 42
From: Doha
If you arrive at the aircraft and APU is already running, it means the maintenance has turned it on and has done the APU fire test already
Joined: Jun 2001
Posts: 3,780
Likes: 0
From: Surrounded by aluminum, and the great outdoors
reason I asked, our serial number 321's APU would shut down if the APU fire test were activated...cant say for sure if ALL 321's do this or not, all of ours did
Joined: Jul 2006
Posts: 1,100
Likes: 111
From: Somewhere over the rainbow
Not necessarily so. That’s like requiring you to do and APU fire test as you taxi in before you switch it on before engine shut down. You wouldn’t. Why would you presume engineers will always do a test. Your preliminary cockpit procedure requires you to do it on YOUR first flight of the day.
Joined: Jun 2007
Posts: 3,443
Likes: 39
From: Wanderlust
The FCOM Regarding the cockpit preparation assumes the APU was not running. It’s not very clear IMHO that we are supposed to test the APU if already running.
pineteam, it is very clear. I have produced airbus FCOM SOP. It just checks the circuitary. There's no problem what so ever.
Joined: Jun 2006
Posts: 190
Likes: 0
From: CASEY STATION
I think Airbus are very clear. First two lines under the title GENERAL - PRELIMINARY COCKPIT PREPARATION. Items marked with an asterisk are completed for a transit stop with no crew change. Otherwise complete all items.