identification collars for c/b
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identification collars for c/b
according the QRH B737 ( but it's valid for any a/c) in some failures (landing gear ,loss both gen ditching etc etc ) we have to reset some circuit breakers....is it important to have on involved c/b , the colored identification collars ?is it mandatory ? are they recomended ?
I appreciate your help.
I appreciate your help.
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Popped C/Bs
ALL manufacturers and ALL operating carriers (usually) have clearly stated procedures for addressing C/B fault indicators. Some allow a reset and some say hands-off. To a degree, it depends upon what service or function the C/B is protecting. For a non-essential function, I'd leave it alone. For a truly essential function especially during a critical phase, might have reset ONE time, even if violating SOP. Never forget: when engines run, Capt. controls all and may fudge a few SOPs if justified. A second reset? Probably not. At least during the first attempt, remember that C/Bs themselves can and do fail. Dirt, corrosion happen.
As for tagging, collaring, logging and notifying Mx engineers, pocket-note it until parked. With or without the essential service, you still have an airplane to fly!
As for tagging, collaring, logging and notifying Mx engineers, pocket-note it until parked. With or without the essential service, you still have an airplane to fly!
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These are fitted by operator maintenance personnel, not manufacturer.
No
Operators choice; some find it easier to identify certain CB with collars (e.g. CVR) to aid crews when requiring to pull them in a hurry (e.g. evacuation)
No
Operators choice; some find it easier to identify certain CB with collars (e.g. CVR) to aid crews when requiring to pull them in a hurry (e.g. evacuation)
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There have been many occasions when I've wanted to find a CB. On various Boeings I've re-stored systems and avoided problems via a CB re-set. Some QRH's call for pulling CB's. Many yonks ago I flew with an operator who had a CB 'map chart' in the tech-log. There is also one in Bill B's & others Boeing reference books.
I then flew for various young growing operators and asked them to include such a 'map chart' in their tech log. Sadly it never happened. It would certainly avoid much wasted time when identifying a CB was required.
I then flew for various young growing operators and asked them to include such a 'map chart' in their tech log. Sadly it never happened. It would certainly avoid much wasted time when identifying a CB was required.
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As usual, RAT 5 +/- nailed it (OK, mostly agreeing with me?) Truth is, when you've got a C/B problem, something is out of service. The non-essentials (galley, IFE etc.) may be ignored, but if a popped breaker governs a truly essential system, one Must have a look and consider a reset - and to hell with SOP. Unless you are more than typically visually and cognitively gifted and a S&R pilot, you will need some instruments. Recover them if you can.
One technique is to wait... let things cool down for a bit and then punch the breaker back on only during final. Have heard this more than once, but (+++) never had to do so.
Today's flying machines are complex. You have two jobs: S&R or otherwise, fly it safely Second is a thorough and complete understanding of the systems, far more demanding than S&R flying of even the A380. The SIM instructors will weed out those that fail the systems exams, but who really checks the S&R skills of the Super Heavy Drivers? Those truly qualified to make such checks can be counted on one hand. With the potential to have >500, perhaps >600 souls on board, that troubles me - often enough that I won't ride the A380. I know the B74x series in my sleep, but the history of that other big one remains limited - as a 99% FBW airplane. When a B74x breaks, we know what to do. When the A380 breaks, only a few know - and the best of class (very senior and very sharp) are already retired or will retire soon. That knowledge base and direct experience should be retained in some form. If AB knows the details - likely - they share little beyond the FBW directives and offer zero education toward hand flying their airplanes, even in direct mode, thinking it will never happen. Wrong and a poor policy. but that is their mantra. Ouch.
One technique is to wait... let things cool down for a bit and then punch the breaker back on only during final. Have heard this more than once, but (+++) never had to do so.
Today's flying machines are complex. You have two jobs: S&R or otherwise, fly it safely Second is a thorough and complete understanding of the systems, far more demanding than S&R flying of even the A380. The SIM instructors will weed out those that fail the systems exams, but who really checks the S&R skills of the Super Heavy Drivers? Those truly qualified to make such checks can be counted on one hand. With the potential to have >500, perhaps >600 souls on board, that troubles me - often enough that I won't ride the A380. I know the B74x series in my sleep, but the history of that other big one remains limited - as a 99% FBW airplane. When a B74x breaks, we know what to do. When the A380 breaks, only a few know - and the best of class (very senior and very sharp) are already retired or will retire soon. That knowledge base and direct experience should be retained in some form. If AB knows the details - likely - they share little beyond the FBW directives and offer zero education toward hand flying their airplanes, even in direct mode, thinking it will never happen. Wrong and a poor policy. but that is their mantra. Ouch.
.. FWIW this is the advice for the 777 from the QRH. (TBH I Can't think of any non-normal demands a CB be pulled).
In flight, flight crew reset of a tripped circuit breaker is not recommended. However, a tripped circuit breaker may be reset once, after a short cooling period (approximately 2 minutes), if in the judgment of the captain, the situation resulting from the circuit breaker trip has a significant adverse effect on safety. On the ground, flight crew reset of a tripped circuit breaker should only be done after maintenance has determined that it is safe to reset the circuit breaker.
Flight crew cycling (pulling and resetting) of a circuit breaker to clear a non-normal condition is not recommended, unless directed by a non-normal checklist.
Flight crew cycling (pulling and resetting) of a circuit breaker to clear a non-normal condition is not recommended, unless directed by a non-normal checklist.
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often enough that I won't ride the A380.
What a load of rubbish. Of COURSE you fly the aircraft when something unexpected happens. But the thing that will kill you is poor decision making, and that's why there are structured DM tools, and why Airbus is so neurotic that failure management / ECAM is followed so carefully - because it directly impacts on the subsequent decision making process.
Ultimately, the job of flying is not particularly challenging which is exactly why the FO is given control in unusual scenarios (SFF?) while the Captain runs abnormal checklists and handles cabin/ATC comms.
Give me a modern, effective, systems manager who demonstrates excellent teamwork over the ancient sky-god who can "fly the arse off it" but will throw his toys out of the pram if anyone dares question his course of action.
At the risk of being boring, can I please warn pilots against having their own plans for reseting C/Bs. Aircraft have lost control and crashed because pilots have made their own decisions about pulling C/Bs but not appreciating how the systems interact.
Similarly, I am always a little nervous when pilots have their own C/B maps and little ways of 'fixing faults'. Doing so on the ground with engines and systems off is one thing, but could lead to a mindset that might cause serious controllability problems in the air.
Also, different aircraft in the fleet may have breakers in different places, so having a personal note that says pull X18 and C27 to reset the toilet or whatever, might not be the right ones on the day and could get you into a bad situation.
QRH and Maintrol are the only sources we should follow for pulling or resetting C/Bs
PS
Breakers pop when they sense that too much current is flowing. Too much current running through a wire or item of equipment will cause overheating, melting and possibly fire - which is the very last thing we need !
If a breaker keeps 'nuisance' popping, put it in the tech log - it means there is an overcurrent problem somewhere which should be sorted out.
Similarly, I am always a little nervous when pilots have their own C/B maps and little ways of 'fixing faults'. Doing so on the ground with engines and systems off is one thing, but could lead to a mindset that might cause serious controllability problems in the air.
Also, different aircraft in the fleet may have breakers in different places, so having a personal note that says pull X18 and C27 to reset the toilet or whatever, might not be the right ones on the day and could get you into a bad situation.
QRH and Maintrol are the only sources we should follow for pulling or resetting C/Bs
PS
Breakers pop when they sense that too much current is flowing. Too much current running through a wire or item of equipment will cause overheating, melting and possibly fire - which is the very last thing we need !
If a breaker keeps 'nuisance' popping, put it in the tech log - it means there is an overcurrent problem somewhere which should be sorted out.
At the risk of being boring, can I please warn pilots against having their own plans for reseting C/Bs.
It might have been OK "back in the day" but nowdays you'll no doubt find the breaker for the 1st class coffee machine also feeds a sneak circuit to some aspect of Autopilot A or the FBW system.
That's why our company has the SOP as written by Boeing and even our ground engineers are very reluctant to recommend cycling breakers to resolve a single system problem.
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The Airbus has green coloured CB's for a monitored CB (ECAM will tell you its popped). Black colour for non-monitored.
There are red collars around the wing tip brakes to stop you pulling them and making the situation worse!
There are red collars around the wing tip brakes to stop you pulling them and making the situation worse!
Last edited by applecrumble; 29th Mar 2017 at 17:46.
I´m sorry if this question appears a bit thick, but does your QRH not say exactly which CB needs pulling or resetting if a procedure requires such a step?
On my type, there are some such abnormal procedures. The exact name of the CB and the general area on the panel where it can be found is clearly stated in each of those (the DH8D CB panels are generally organised according to the busses they are fed by). Exact coordinates are missing though, there may be aircraft in the fleet with slightly differing locations of individual CBs.
If needed, the relevant CB is looked up, its name as found beside it reconfirmed with the QRH in order to avoid misidentification, and then it is subjected to the actions required by the procedure. This method has worked quite well for many years already.
Cluttering the panel with different-coloured collars (maybe sorted by AMM chapters?) would in my opinion not help much due to the sheer amount of CBs that are referred to by individual procedures and on top of this might as well block the view on other CBs, making the inspection before each flight harder.
On my type, there are some such abnormal procedures. The exact name of the CB and the general area on the panel where it can be found is clearly stated in each of those (the DH8D CB panels are generally organised according to the busses they are fed by). Exact coordinates are missing though, there may be aircraft in the fleet with slightly differing locations of individual CBs.
If needed, the relevant CB is looked up, its name as found beside it reconfirmed with the QRH in order to avoid misidentification, and then it is subjected to the actions required by the procedure. This method has worked quite well for many years already.
Cluttering the panel with different-coloured collars (maybe sorted by AMM chapters?) would in my opinion not help much due to the sheer amount of CBs that are referred to by individual procedures and on top of this might as well block the view on other CBs, making the inspection before each flight harder.
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according the QRH B737 ( but it's valid for any a/c) in some failures (landing gear ,loss both gen ditching etc etc ) we have to reset some circuit breakers....is it important to have on involved c/b , the colored identification collars ?is it mandatory ? are they recomended ?
I appreciate your help.
I appreciate your help.
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I'm going to admit I've re-set systems via an pull/push CB manoeuvre. Indeed, when transitioning to B767 we were taught to re-set a failed FMC via the CB. It certainly wasn't a QRH item, it was an engineering one.
Since then, on various Boeings, I've reactivated VHF, VOR, FMC, Transponder. Two in the air and others on the ground. The 2 airborne avoided a diversion to a maintenance base as the MEL would have grounded the a/c.
However, the sting in the tail. B767 out of LGW, many moons ago, on its way to Canaries; A/T would not engage on takeoff. They continued, as you do, and then, during the mid-level climb, Himself decided on a CB pull/push. I do not know if the A/T recovered, but the RAT deployed. The electrons and circuits had detected, in their mind, a double engine failure when the CB was pulled. OMG Lordy Lordy. They returned LGW for a red-faced landing. Engineers asked why not continue to destination and reset RAT on the ground; RAT has no speed or ALT restriction. Oops! The crew were now out of hours so the debacle grew & grew.
There are some CB's that you might be sure affect only a single non-critical system, and others to be left well alone. I suspect on many of today's Star Wars jets the electrical spaghetti behind many switches has tentacles far beyond our imagination.
An old rule of thumb from carpentry days; measure twice cut once. Re-paraphase for resetting CB's. And be aware of the difference between resetting a popped CB and resetting a system via pull/push.
Since then, on various Boeings, I've reactivated VHF, VOR, FMC, Transponder. Two in the air and others on the ground. The 2 airborne avoided a diversion to a maintenance base as the MEL would have grounded the a/c.
However, the sting in the tail. B767 out of LGW, many moons ago, on its way to Canaries; A/T would not engage on takeoff. They continued, as you do, and then, during the mid-level climb, Himself decided on a CB pull/push. I do not know if the A/T recovered, but the RAT deployed. The electrons and circuits had detected, in their mind, a double engine failure when the CB was pulled. OMG Lordy Lordy. They returned LGW for a red-faced landing. Engineers asked why not continue to destination and reset RAT on the ground; RAT has no speed or ALT restriction. Oops! The crew were now out of hours so the debacle grew & grew.
There are some CB's that you might be sure affect only a single non-critical system, and others to be left well alone. I suspect on many of today's Star Wars jets the electrical spaghetti behind many switches has tentacles far beyond our imagination.
An old rule of thumb from carpentry days; measure twice cut once. Re-paraphase for resetting CB's. And be aware of the difference between resetting a popped CB and resetting a system via pull/push.
With the increasing amount of bumpf that is being jammed in to the FMC they were becoming clogged up with errant data. It was becoming an engineering function to pull the CB's of the FMC's every turn around. That would clear all of the latent data. Crews then started doing it if they saw it hadn't been done (it's easy to tell on a Boeing). However that totally isn't sop, hasn't been published anywhere and engineering probably don't know it's happening.
I wonder if it will have unintended consequences.
I wonder if it will have unintended consequences.
Yes, and that is the problem. Those poor sods who decided to reset the FACs in flight on an Airbus found out why this is a very very bad habit to get into.
Dare I ask if the Boeing FMC memory clearing procedure was written into the tech log every time ?
Dare I ask if the Boeing FMC memory clearing procedure was written into the tech log every time ?
