Anyone remember a B727 where the crew pulled the slat CBs and cracked a notch of flap to improve cruise performance.
Ah, one of those favourite cautionary tales, trotted out to back up an instruction of "don't touch that!"
Gibson's dive
http://en.wikipedia.org/wiki/TWA_Flight_841_(1979)
National Airlines DC-10 "pull the CB for N1 tach"
http://en.wikipedia.org/wiki/Nationa...ines_Flight_27
It is important to separate the folklore from the actual accidents. As alluded to above, the NTSB investigations were not beyond reproach. In the 727 slat incident, there was a presumption of guilt of the pilot in command. A witch hunt. The NTSB hypothesis was not supported by the subsequent test flight. In the DC-10 incident, the crew were castigated for a failure of discipline. However, the investigation revealed that the fan resonance that caused the uncontained failure of #3 would have remained undetected and happened at some future time.
What is relevant to the topic under discussion is ... the 727 "C/B pullings" are not applicable.
IF the crew had pulled the Slat C/B, they were disabling a warning/protective system. It was a system that had limited interrelationships with other systems.
The DC-10 incident is a little closer. The crew hastened the incipient failure of the #3 by doing something the system designer never intended.
Current generation airliners have dropped most 'trouble shoot' procedures in abnormal checklists. Philosophy now seems to be - isolate the fault, then (a) land at nearest suitable aerodrome or (b) if conditions permit with the system disabled, continue.
AFAIK, the reason for replacing a troubleshoot QRH with an isolate then land at nearest suitable is the increasing complexity of the electronic (read micro computer based) control and command systems.
Pulling a slat C/B just used to disable the anti-extend mechanism.
Do that on a current generation airliner and you might disable the stall protection system and force the FADEC onto channel A which the EEC #2 previously set as FAULT, so FADEC then defaults to N1 mode instead of EPR, now autothrottles not available, etc... if you get my drift.
The benefit of all the digital electronics in flight control computers, ADIRUs, brake control units, proximity sensor units, is that they can monitor
other systems for faults and failures and modify their status to suit. The drawback is myriad knock on effects for seemingly 'unrelated' system due to a fail/fault in one system, that never existed in second gen airliners.
Pulling C/B in flight? Only if QRH says 'do it' in response to an ECAM/caution/warning.
Pulling C/B on ground to reset computers due to fault indications?
"Incredibly dangerous, never never never!" or
"Its on the ground, and this handy guide has not let me down yet!"
I think the answer is somewhere in between.
Unofficial pilot notes were a good resource for thinking pilots, and a potential trap for the foolish and impatient. But
so 'last century!' You now have unprecedented access to first hand advice via that mobile phone in your pocket. Iridium perhaps? HF even?
Call base. Speak to an engineer that knows the system. If he/she says 'give it a try' then go ahead. If he/she is reluctant, then you would be a mug for following your 'pilot notes.'