CB resets - A320 fleet

[nnc0]

You've left the gate and subsequently get an indication of some system fault. You suspect it's a minor issue and figure a reset of the computer will resolve the problem.

Where do you go for that circuit breaker reset procedure if it's not in the QRH?

The background here is that I'm wondering how you handle these type of non QRH resets since Airbus stopped supporting their SIL addressing CB resets back in 1999.

Do maintenance relate the TSM procedure to you or are the rules such that they themselves need to come out to do it?

[guiones]

Airbus philosophy:

If not in the QRH, it is not a documented Pilot procedure, CYA and stay away from it. Let maintenance do it themselves. We don't ask them to fly for us.

My .02

[nnc0]

FCOM 3.04.24 P2
"On the ground almost all computers can be reset, and are not limited to the ones indicated in the table (FCOM or QRH table)"

That says to me that crew can reset almost anything - the question is what and how. The Trouble Shooting Manual has a simple easy to use section on what cbs affect which computers so I think we should carry it on board.

[Old Fella]

Are you asking about "Resetting" or "Cycling" a system CB? Thinking as one replaced by computers I would suggest that whilst still safely on the ground, and if unsure of the effect of "cycling" a CB, it would probably be prudent to get on the radio to the technicians for advice. The pertininent words in the offering from nncO are "ALMOST all computers can be reset".

[Dan Winterland]

My company's policy is that if the computer is in the reset list, then you can do it. If not, then it's a maintenace action.

Common sense really.

[Insider Trader]

Resetting CB's
Are you asking about "Resetting" or "Cycling" a system CB? Thinking as one replaced by computers I would suggest that whilst still safely on the ground, and if unsure of the effect of "cycling" a CB, it would probably be prudent to get on the radio to the technicians for advice. The pertininent words in the offering from nncO are "ALMOST all computers can be reset".


Reset Switchs and CBs are different. Reset Switchs give Tech crew the facility to try and erase erronious messages. Circuit Breakers are used as a function of maintenance and should NOT be touched by Tech crew. To me it seems fairly obvious. If the tech crew can not erase a message within the scope of the FCOM, then bring it back to blox. That is why we have maintenance divsions.

[Old Fella]

Insider Trader, you misunderstood my question. I asked if the original question related to "Re-setting" (as in re-setting a tripped CB) or simply "Cycling" it (as in manually tripping and re-setting). As a former F/E I would like $10 for every time tripping and re-setting a system CB resulted in getting a system back in operating condition. (I would have been able to retire even earlier than I did) The only real riders I put on my actions were that I had to be sure I knew what the effect would be on the aircraft and that I fully advised the Captain of what I wished to do and why. It was then his call. As for CB's NEVER BEING TOUCHED BY TECH CREW, many QRH checklists call for certain CB's to be tripped, and sometimes later re-set, as either an attempt to rectify a problem or isolate a fault.

[Dream Land]

Although safety is the priority, it depends on what culture you're operating in, where I work we will reset anything posible prior to departure, after lift off it's strictly per QRH.

[FlightDetent]

Listen to Dream Land and go slowly read the full the pre-face to Computer Reset in QRH. There are two or three tiny extra bits you may find helpful. Of course we are speaking about "computer reset (using C/B)". "Tripped C/B re-engagement" is a different cup of tea, policy conveniently located on the same page.

FD (the un-real)

[nnc0]

Most of you seem to imply c/b resets are the exclusive domain of maintenance. Below is a the C/B reset discussion in the FCOM and from the discussion it seems to me to be pretty clear - on the ground, with a few obvious exceptions, flt crew can do a c/b reset of most any computer.


COMPUTER RESET
The normal purpose of a circuit breaker (C/B) is to protect wiring against short circuits, and to isolate equipment for maintenance.
Another C/B function involves digital computers : The reset function. When a digital computer behaves abnormally due to an electrical transient, for example, the abnormal behavior can be stopped by briefly interrupting the power supply to its processor.
The flight crew can reset most of this aircraft's computers with a normal cockpit control (selector or pushbutton). However, for some systems, the only way to cut off electrical power is to pull the associated C/B.

PROCEDURE
To perform a computer reset:
- Set the related normal cockpit control to OFF, or pull the corresponding reset pushbutton or circuit breaker
- Wait 3 seconds if normal cockpit control is used, or 5 seconds if a circuit breaker is used (unless a different time is indicated)
- Set the related normal cockpit control to ON, or push the corresponding reset pushbutton or circuit breaker
- Wait 3 seconds for the end of the reset.

WARNING
do not reset more than one computer at the same time, unless instructed to do so.

.........

- On ground, almost all computers can be reset, and are not limited to the ones indicated in the table. Following computers are not allowed to be reset in all circumstances :
ECU (Engine Control Unit on CFM engines) or EEC (Electronic Engine Control on IAE engines) and EIU (Engine Interface Unit) while the engine is running.
BSCU (Brake Steering Control Unit) if the aircraft is not stopped. (Refer to 3.04.32).
- In flight, as a general rule, the crew must restrict computer resets to those listed in the table, or to those in applicable TRs or OEBs. Before taking any action on other computer the flight crew must consider and fully understand the consequences.

CAUTION
Do not pull the following circuit breakers :
- SFCC (could lead to SLATS/FLAPS locked)
- ECU or EEC, EIU.

Again, it seems pretty clear to me that the above would provides for crew to do c/b resets for simple faults if the crew only new which c/bs to cycle.

If maint come out to the aircraft, they first refer to the troubleshooting manual and if the reset procedure in there doesn't work then it's RTG for further evaluation and/or pull it out of service. All I want to do is put those TSM reset procedures in the flight deck so crew can refer to them and thus save the delay of calling maint to do the same thing.

Nobody does that?

[Cardinal]

nnc0, that's how our lot interprets it. The "list" is included in our manuals, and there's even a place in the log sheet to indicate computer resets. Works well.

[FHA]

Hi nnco. Avionics man here.
In our outfit, if it's not in the QRH, our pilots will do the reset having consulted Maintrol (MCC to you guys?), subsequently staying in contact while carrying out their instruction.
The Captain then makes a techlog entry "for info" stating the fact and "reset successful". :)

[Hand Solo]

If the company don't approve a CB reset then don't do it and call the engineers out. However if you were to slip and catch a CB on your sleeve, pulling it out, then resetting it whilst P2 was thumbing the manual looking for engineerings radio freq then you might find the problem disappeared.

[nnc0]

Appreciate the feedback, pro and con. Thanks very much fellas (and gals?).