I’m not quite sure where your “sexual innuendo” comment stems from,
At that point I said "Blow me! Enough is enough"! Perhaps I used some other phrase other than "Blow me" - but I was a tad stressed at the time!
regarding who can define when an aircraft is fit to fly or not … I believe it must start with an Engineer who will have a whole raft of things to do which are not obvious to a Pilot.
As a pilot I disagree with that statement. As a mechanic---what some of you call an "engineer," I disagree with that statement.
An inoperative, or "defective" component is located. It's referenced in the fault manual or MEL. A determination is made as to whether it's acceptable for flight or not. It's handled accordingly. Very simple. Not exactly rocket science. There's plenty that a pilot has to consider that isn't on the "engineer's raft." Certainly a MEL item may require maintenance action, but it's not the mechanic's call as to whether the pilot will fly with that condition or not. That responsibility, and that right, sits squarely in the lap of the pilot.
Should you not as a pilot request a defect repaired as soon as possible, instead of flying with the defect for a long time.
What if a new error occurs and this becomes much more serious because it already has a flaw in the system.
A "defect" which has been properly deferred is no longer a "defect." It's been properly addressed. If an additional problem arises, then that problem shall be addressed in turn, on it's own merits, applicable to the conditions that exist.
Deferrable items come with specific time intervals for which deferral is allowed.
I may get in an airplane with three deferred items, and fly it on a six or eight hour leg. I get out of the airplane and go to the hotel. When next I get to the airport, a different airplane will be waiting. At some point during my typical three week tour, I'll likely get in one of the same airplanes again, and it may o rmay not have the deferral.
There will be a host of others who have seen and considered that deferral...not just me. If the airplane is properly altered and is both legal and safe, then I'm not goin to insist that the maintenance deferral interval is cut short out of an arbitrary whim. I act safely and legally, but it is not my intention nor place to dictate how the company will do business.
The systems on the aircraft has been designed for optimum safety, every time a system is flawed, its removes a part of safty.
Not at all true. We have another thread going on a similiar topic presently. This last week I climbed into an airplane in which the flight director was deferred. The autoflight system consists of an autopilot/flight director, an autothrottle, and a yaw damper. On that particular airplane, the autothrottle went unused for the duration of the flight. The flight director was hardly missed, and I spent much of the flight without the autopilot in use, including the approach and landing. Safety was in no way compromised. With one component of the autoflight system inoperative and properly deferred, a failure in another component of the system would scarcely have been missed, and certainly would not have impacted safety.
One can hardly made such a broad brush assumption that safety is impacted because a component, applicance, or part has been deferred.
On another trip, an airplane was delayed away from a maintenance base where the flight management system would normally be updated with a current data base. I arrived to pick up the airplane to find the FMS database out of date...no longer current. A deferral per the MEL was arranged, and the airplane safely, and legally flown on a trip that terminated in a maintenance base. There, the update was arranged. We were required to manually verify each waypoint as it couldn't be extracted from the database, and we flew a VHF approach on arrival...which wasn't really any different than any other day because I always verify the lat long on each waypoint against the flight plan and chart anyway. Just not a big deal.
I can not imagine that they will put many additional systems into the cockpit, just because you have to be able to fly for longer time without repair.
Irrelevant.
Systems are not put into airplanes purely as spares to be used while other systems are deferred, but that's neither here nor there. Equipment, systems, parts, applicances, etc, can be deferred. Period. When they are deferred, it's done safely and legally, and thus ends any concern regarding the matter. A function of the MEL is the establishment of time intervals for the deferral. In my experience, seldom do the deferrals go this long, but if they do, what of it? There's a reason that the item has been given these limitations, and so long as it's safe and legal, there's little argument to be made.
Defects must be repaired as soon as possible
Deferred items are not "defects," and no, they don't need to be repaired as soon as possible. They need to be repaired within the time intervals specificed for the deferred item...time intervals set forth by the manufacturer, by the governing body, and by the operator in an approved program.
Again, a known problem isn't simply let go willy-nilly. It's addressed in accordance with a well regulated and considered program of maintenance...it's not as though a deferred item is simply ignored. When a minimum equipment list or configuration deviation list program is applied to a discrepancy, then that item has been addressed by the maintenance program.