First I have to admit that I have no idea what FAA regulations said about passengers taking part in controlling an airplane in 1989, but I guess it was at least frowned upon, even if the passenger happened to be a pilot.
The United Airlines flight 232 made a stunningly successful "landing" at Sioux City airport, much due to the fact that they took an extra crew member from the cabin to control the throttles of their severely disabled aircraft.
Unfortunately 112 people lost their lives as the plane cartwheeled after a very rough touchdown, and one might ask what is so successful about that...
well: 184 people survived a situation that was in subsequent simulations deemed to be impossible to manage.
The throttle operator was a UA training check airman Dennis Edward Fitch, riding as a passenger on this ill-fated flight.
It has been stated in many sources again and again, that without his presence in the cockpit, the outcome would have been much worse, even the worst possible.
It just so happened, that Fitch had been practicing a similar scenario in a simulator after a fatal crash of Japan Airlines flight 123 in 1985.
The reason of that crash was total loss of hydraulics, Fitch wanted to find out if an airliner could be controlled with throttles only.
Luckily, it was somewhat possible.
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The rules say to do whatever necessary to ensure safety of flight.
91.3 Responsibility and authority of the pilot in command.
(a)
The pilot in command of an aircraft is directly responsible for, and is the final authority as to, the operation of that aircraft.
(b)
In an in-flight emergency requiring immediate action, the pilot in command may deviate from any rule of this part to the extent required to meet that emergency.
(c)
Each pilot in command who deviates from a rule under paragraph (b) of this section shall, upon the request of the Administrator, send a written report of that deviation to the Administrator.
aviation.stackexchange.com/users/46356/Dean F.
As pointed out above pilots may deviate from any regulation in the event of an emergency per §91.3(b).
One of the more common events is a civilian aircraft making an emergency diversion and landing at a nearby military airbase, such as this 777 flight which diverted to Erickson AB, Shemaya, AK .
The OP brings up the case of Cactus 1549.
But what Sully and Stiles did in powering up the APU first wasn’t a violation of the rules per se, though I’m sure there are plenty of odious airline sim
check pilots that cut themselves on their overstarched undershirts who would disagree with this.
This even brings up an interesting discussion I once had with a flight instructor examiner I knew who had been a Air Safety adviser to Korean Airlines.
He told me he once conducted a systems discussion with a group of KAL 747 pilots in regards to understanding their systems in an emergency.
The KAL pilot corps at the time apparently handled their pilots in a very regimented and militaristic fashion.
When the chief pilot walked in, they all jumped to their feet and stood at attention, etc.
So this examiner guy walks up to the front of the group of the group and asks them: “Ok, so what is the emergency procedure for an engine fire on a 747-400?”
The entire group barks out the QRH entry for this contingency at the top of their lungs perfectly and in unison.
“Okay.......so what two things do you do in the event of an engine fire if you only have time to do two things?”
Dead silence.
The entire room stares blankly back at him like a second grader at a spelling bee asked to spell ‘photosynthesis’.
OEM approved procedures, standardized general operating practices and legal regulations for aviation are great guideline for safe and reliable operations but they can’t always cover every contingency perfectly.
A fundamental knowledge of your aircraft and it’s systems from a correlation level can come in real handy sometimes if you encounter something serious that’s not been documented.
It’s
something test pilots know all too well, as it can allow them to make very judicious choices on flight test plans and handle unforeseen problems once in the air.
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In 2017 an MD-83 aborted takeoff above V1.
The pilot was widely criticized for that, which was against a lot of rules and conventional wisdom.
The NTSB report determined that aborting above V1 was the most correct thing to do in this case. https://www.planeandpilotmag.com/article/ntsb-report-how-this-pilot-saved-116-lives/#.XkzGlopOmhA
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There have been cases with incorrectly wired controls , with the aircraft doing the opposite action than such a wrongly wired control commands.
Then the narrow rules about how to use the control to achieve intended action must be completely reversed, moving the stick in the opposite direction.
Doing so does not break the wider rules that cover such malfunctions.
But I imagine how difficult is to realize them happening at the first place.
This is the main reason I would never like to have just a robot in the cockpit.
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I will note that in maritime law there is the General Prudential Rule which states that avoiding a collision takes precedence over strict adherence to other rules and regulations.
I would have to believe that there are similar provisions in aviation rules.
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I wonder if there is an incident that pilots saved the plane or minimized the damage by bending or breaking the rules like Sully? (As it's known  Sullenberger  started the APU at first which was the 15th thing in QRH.)  Thanks in advance.
Has any accident been prevented by bending or breaking the rules?
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<accident-investigation><crew-resource-management><rules-of-the-air>
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The rules say safety is paramount and pilots may deviate from any regulation in the event of an emergency per §91.3(b).  There have been a number of crashes averted by bending the rules. They include the  United Airlines flight 232  made a stunningly successful "landing" at Sioux City airport, much due to the fact that they took an extra crew member from the cabin to control the throttles of their severely disabled aircraft.  One of the more common events is a civilian aircraft making an emergency diversion and landing at a nearby military airbase. There have been such instances, like the landing of United Airlines flight 232 where they took an extra crew member to help control the aircraft, civilian airctaft landing urgently at military bases, a case of an MD-83 aborting takeoff above V1, or cases of incorrectly wired controls that need deviation from standard procedure to be operated. However, the main rule, above all else, is that the pilot must take whatever action deemed most efficient for the safety of the flight.
There have been such instances, like the landing of United Airlines flight 232 where they took an extra crew member to help control the aircraft, civilian airctaft landing urgently at military bases, a case of an MD-83 aborting takeoff above V1, or cases of incorrectly wired controls that need deviation from standard procedure to be operated. The main rule, above all else, is that the pilot must take whatever action deemed most efficient for the safety of the flight.