Check Flights and Pulling Circuit Breakers
 

Check Flights and Pulling Circuit Breakers

Industry thoughts/rulings/legislation on pulling circuit breakers to fail systems on high performance aircraft during check flights in aircraft (not simulator flights)?

No harm at all. Simulates that "'what-the?" factor we need.

Yep, Sounds sensible. Why not expand the policy to allow a check pilot to turn off a hydraulic system or trip a genny offline to give the crew a real world handle of a non normal?

Why not take it one step further and set fire to one of the engines, give the guys real world training...../s

You answered your own question, a high performance aircraft. Something described as high performance and that has capacity for hydraulics and generators should have a simulator, and that’s where failures are practiced, not in the real aircraft.

One of the considerations which most either forget (or never knew) relates to what is on the service end of the C/B. Just because it is labelled "XYZ" doesn't give you any guarantee that it doesn't also provide power to "ABC" and "RST". The electrical engineering folk who do the ELA work will make a point of finding out and knowing and the OEM procedures can be presumed, likewise, to be based on knowledge, rather than well-intentioned guesswork.

You pull C/Bs at your potential peril unless you either have done all the homework or are following OEM or specialist electrical guidance.

Well it depends on what's being checked, now doesn't it? Are we checking the crew or the plane?

Wasn’t a Westwind lost on departure out of Sydney, when the circuit breaker was pulled on the A/H and the turn and balance indicator was wired incorrectly?

It not 1960 just say no !!

Take a moment to Giggle “National Airlines Flight 27” in November 1973 before doing anything like this in flight!

The company I work for specifically does not permit this to happen - my understanding is that it is partly to allow deliniation between an actual issue and simulated. The discussions ive had from checkies with regards to failures/circuit breakers out etc have all had the same benefit as them pulling a breaker.

However, imagine the situation - they pull a circuit breaker on the pressurisation control as part of a check, its identified and reset... but the system faults out. It'd be a bit hard to explain that in the report.

I wonder what the paying travelling public would think if they knew the folks up front were purposely disabling perfectly good equipment.
It's kind of similar to requesting a Non-Precision Approach when a Precision approach is available. Although safe, the safer option is the ILS.
Our jobs are to get the fare-paying passengers from A-B in the SAFEST manner possible. Pulling cb's would not be included in this job description.
There is a fantastic tool called a simulator for this sort of thing.

Short answer NO !

We have two levels of training and testing for good reason.
The simulator is where we train for abnormal and emergency operations with degraded systems.
Line checking SHOULD be focussed on SOP and normal operations.
It is fine to explore technical discussions in the post flight debrief, but in every operator with whom I have flown this is strictly forbidden, and believe that underlying this are regulations stating such.

From a purely professional perspective, where is your defence should an incident occur for a deliberate act of this nature ?

There is no defence, you would be toast for doing it, and toast for allowing it to happen as an aircraft commander.

TR

VH-IWJ, in 1985

https://www.pprune.org/pacific-gener...l#post10767811

Early BOAC days of the "real" Boeing 707 - i.e. not the simulator at that time, the Stabiliser Runaway drill was to shout "Runaway Stabiliser" then first stop the rapidly turning wheel situated on the sides of the centre console, maybe breaking a finger nail, or even a wrist (!) in the process, cut the adjacent switches on the console, and call for the circuit breaker situated on the overhead panel to be pulled by the Flt. Eng. then raise the handles stowed in the wheels and manually re-trim by hand.

At around 5,000 ft over the Severn Estuary the Trg.Capt. ran the stabiliser nose down. The trainee co-pilot stopped the wheel, cut the switches and called for the CB to be pulled. " Very Good, now recover" said the Trg. Capt. The trainee pulled back on the control column to try to reduce the rate of descent, re-engaged the switches, and called for the CB to be re-set, but .... pulling back on the column was creating so much "G" force that the Flt. Eng. couldn't raise his hand high enough to reach the CB. By now the aircraft was seriously descending, and the force over the stabiliser was such that both pilots together were unable to turn the wheel with the manual handles, of course the answer would have been to momentarily push further forward to relieve the load, and then wind back but with the ocean rapidly filling the windscreen, who would ? Eventually, with the Flt.Eng. bracing his feet against the forward panel, and a hand on each control column, all three managed to pull hard enough to stop the descent - about 500 ft above the water apparently.

Following that CB's were not pulled, until the simulator sessions took over.

Murphy is always with us.

Can you imagine the feverish moustache twirling over a warm pint at the local ale house that evening? :oh:

In the airline I spent most of my life flying for, unless the check list called for it, we were not allowed to pull or reset any circuit breaker until we received permission from Maint Control.
Either via HF or ACARS.

Pulling a CB on a system that is working perfectly fine will nullify the insurance coverage for the flight. Try explain that to the passengers.

Early BOAC days of the "real" Boeing 707

.. getting on to 30 years ago. A sobering result of doing things which are not appropriate to do in an aeroplane.

Big no no! I know it was pretty common practice in GA years ago by a selected few checkies. If it isn’t in the AFM or SOPs, you’re on your own.

I recall an event that occurred a few years ago in PNG, where a very experienced Captain decided to intentionally disable a primary rudder hydraulic system in a Dash 8 to demonstrate something to the FO. He demonstrated that he was an idiot!

It went pear shaped although they recovered and the Captain was subsequently sacked, and quite rightly so!

It’s also an offence against the regs to do this type of stuff, hence if proven guilty one could end up in a world of pain.

Never pull a CB in an aitcraft in the air. If you do you are looking for trouble. If you look for trouble you may find it. There was a line check full of pax, being carried out in Asia somewhere and the country shall remain nameless. On final the check pilot pulled the A/P CB. the outcome was the P/F couldn't manage the situation and caused an incident.it shouldn't have but it did.

The time to play games, is in the simulator.