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-   -   Military policy on cycling CB's (https://www.pprune.org/military-aviation/619121-military-policy-cycling-cbs.html)

punkalouver 6th Mar 2019 03:56

Military policy on cycling CB's
 
Seems to be a bit of a no-no on the civilian side but what about in the military. An F-14 story I read recently was quite interesting. Of course...it is during combat ops.

"Another mission that stood out was one I flew with LT Larry "Lobes" Sidbury. Lobes was our Training Officer, a phenomenal pilot and warfighter, later he became CO of VFA-31. Anyway, on deck we had an error with the AWG-15 Stores Management System, meaning if it couldn't be fixed we couldn't drop bombs. Lobes said we'd launch and try to figure it out airborne. Airborne I ran all the bits, pulled the circuit breakers and yet the error held firm. I asked Lobes if we should notify the ship and let them launch the spare. He said "hell no, keep pulling the breakers, you have two hours to get it working!" The Tomcat had over 100 circuit breakers in the back that the RIO could access and it was common practice to cycle them to get the offending system back on-line. Well I kept cycling the breakers and low and behold after about an hour we were back in business"


Vendee 6th Mar 2019 07:39

I'm reminded of the A340 ground incident at Toulouse during a high power engine run when the engineer pulled a CB to silence a noisy config warning. Unfortunately, the CB in question (ground proximity sensor) corrected the config error by putting the aircraft in a flight configuration, which meant releasing the parking brake. No chocks were fitted and the aircraft was destroyed.

Onceapilot 6th Mar 2019 07:49

Punka, Mil aircraft operate within a framework of regulations, orders and SOP, just like Civ aircraft. The implications of cycling CB's are similar and, subject to specific proceedures according to type and operator, as you would expect. :)

OAP

Radley 6th Mar 2019 08:06

CB the pulling of
 
OAP, more so these days but back in the day when out in the Atlantic trying to keep hold of a slippery Akula you did what was necessary, safely and with knowledge, to get the job done.🤓

TURIN 6th Mar 2019 09:11


Originally Posted by Vendee (Post 10408260)
I'm reminded of the A340 ground incident at Toulouse during a high power engine run when the engineer pulled a CB to silence a noisy config warning. Unfortunately, the CB in question (ground proximity sensor) corrected the config error by putting the aircraft in a flight configuration, which meant releasing the parking brake. No chocks were fitted and the aircraft was destroyed.

If you mean this one Etih....A340 Toulouse then no. CBs had nothing to do with it.

NutLoose 6th Mar 2019 09:33

Remember the RAF Tristar :)
seized pump and holding in a CB on a run ( BA eng ) resulted in explosion of said pump with a fire to boot and a lot of damage in the wing.


..

BEagle 6th Mar 2019 09:45

During my F-4 course, my nav reset a tripped radar CB about 12 times before letting me know.

I suggested that it might be trying to tell him something and to leave it tripped!

Airbus were rather surprised to learn that resetting tripped CBs was quite routine in the VC10 - whereas in their aircraft it most certainly was not!

Saintsman 6th Mar 2019 11:19

Almost the same as resetting CB's. 'Black' Boxes were routinely re-racked to cure faults.

bvcu 6th Mar 2019 16:54


Originally Posted by Vendee (Post 10408260)
I'm reminded of the A340 ground incident at Toulouse during a high power engine run when the engineer pulled a CB to silence a noisy config warning. Unfortunately, the CB in question (ground proximity sensor) corrected the config error by putting the aircraft in a flight configuration, which meant releasing the parking brake. No chocks were fitted and the aircraft was destroyed.

Not quite correct ! Airbus park brake was not full pressure so on high power run you use one guy on toe brakes to get full pressure. However the ran all 4 engines at high power which no brake system will hold !

ShyTorque 6th Mar 2019 17:09

There is no one answer, military or civilian. The pertinent flight manual for the type is the place to look.....

Lyneham Lad 6th Mar 2019 17:50

Cycling CB's. The aeronautical equivalent to the IT Dept's "do a reboot..."

H Peacock 6th Mar 2019 17:50

There's a huge difference between resetting a non-tripped CB and resetting a tripped CB.

If you know your systems well enough then why not pull the Stores Management computer CB to reset it? It's being used simply as an on off switch. I have done this many times in an attempt to bring a piece of kit on line and often works. That said, you have to know that turning said piece of kit off won't cause further problems.

Resetting a tripped CB can be done with caution, but as for holding in a tripping CB that's asking for trouble.

Onceapilot 6th Mar 2019 17:52


Originally Posted by ShyTorque (Post 10408763)
There is no one answer, military or civilian. The pertinent flight manual for the type is the place to look.....

Yes, I tried to extinguish this dopey thread on my reply @ #3. :rolleyes:


OAP

ORAC 6th Mar 2019 19:38


Dan Winterland 7th Mar 2019 03:20


Airbus were rather surprised to learn that resetting tripped CBs was quite routine in the VC10 - whereas in their aircraft it most certainly was not!
The A330/340 doesn't have CBs accessible in the cockpit - they are all under the floor in the radio electrics bay. There are some reset buttons which look a bit like CBs on the overhead panels, mainly for computers, but CB resets in flight aren't allowed or even possible without going 'downstairs'. If a CB pops, the monitoring system lets you know and you can see which one by looking at the CB systems page on the alerting system.

BEagle 7th Mar 2019 04:27

Hi Dan - I was referring to the A310MRTT. There are some CBs at the Fuel Operator's Station and I was developing abnormal procedures. If a pod failed to respond when the master p/b was pressed, I asked whether the CBs should be checked and if one had tripped, it could be reset.

Much sucking of teeth and "No!" was the answer.

Two's in 7th Mar 2019 12:14


Originally Posted by H Peacock (Post 10408792)
There's a huge difference between resetting a non-tripped CB and resetting a tripped CB.



This!

Resetting a tripped CB is a great way to practice your "Smoke in the cockpit" drills. Using it to cycle a serviceable system is not a terrible idea at a pinch, but ignorance is not bliss when switching power in and out.

TURIN 7th Mar 2019 13:09

The A320 even has an AMM reference for 'computer resets' in ATA chapter 24. Very useful. :O

Surplus 7th Mar 2019 13:23

I guess it depends on the A/C type. Resetting CB's on one A/C was normal (I'm not talking about tripped ones.) Another Air Force and aircraft type it was taboo and they lost a lot of sorties because of it. Who was right?

Timelord 7th Mar 2019 13:34

A USN E2 dropped into Lossie for fuel late one Friday afternoon for fuel en route to the Farnborough air show. Unfortunately the VASS power set seemed not to be compatible with the E2 systems. Every time they tried to start the engines all the power tripped off. With rapidly approaching airfield closures at Lossie and Farnborough the Aircraft Commander and I were trying to get Oceanic to talk to their C130and get it diverted in, , trying to keep the airfield open, talking to Farnborough etc when the VASS sergeant came in and announced all was well, the engines were running and would the AC like to get aboard. Once they were on their way I asked the VASS guy how he had done it, “Easy” he says,” their crew chief in the cockpit, and me in the power compartment holding the CBs in”

I’m not sure that was actually “policy” though!


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