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FAA issues emergency directive on 2,000 Boeing 737 NG, Classic planes

reuters.com

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Re: FAA issues emergency directive on 2,000 Boeing 737 NG, Classic planes

#5
post #2

The official PDF document is here: https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf... I always wondered what the proper terms was for an airplane crash, and now I know: "forced off-airport landing"

Not necessarily. A "forced off-airport landing" could also be the result of an engine failure beyond gliding distance of an airport. Or engine fire, medical emergency in remote area, etc. There are many emergencies that could force an aircraft to the ground, off-field.

Not all off-field landings result in an accident, or "crash".

From our own regulations, NTSB 830 "NOTIFICATION AND REPORTING OF AIRCRAFT ACCIDENTS..." https://www.law.cornell.edu/cfr/text/49/830.2

>Aircraft accident means an occurrence associated with the operation of an aircraft which takes place between the time any person boards the aircraft with the intention of flight and all such persons have disembarked, and in which any person suffers death or serious injury, or in which the aircraft receives substantial damage. For purposes of this part, the definition of “aircraft accident” includes “unmanned aircraft accident,” as defined herein.

So while some off-field landings could be classified as an accident, that would only be the case if the off-field landing met the above definition.

Re: FAA issues emergency directive on 2,000 Boeing 737 NG, Classic planes

#6
post #2

The official PDF document is here: https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf... I always wondered what the proper terms was for an airplane crash, and now I know: "forced off-airport landing"

i also like crashing into a mountain:

https://en.m.wikipedia.org/wiki/Controlled_flight_into_terra...

and in space flight: "off nominal"

Re: FAA issues emergency directive on 2,000 Boeing 737 NG, Classic planes

#7
One of the inspection checklist items:

Measure the clearance between the flapper bushings at both locations on each engine bleed air 5th stage check valve. If the clearance between the flapper bushings is a minimum of 0.004 inch (0.102 mm) at both locations, the engine bleed air 5th stage check valve at that location has passed this inspection.

I knew that aviation engineering dealt with tight tolerances, but boy, it must be difficult to make a call like that when you're dealing with thousandths of an inch. Do field technicians have dependable tools and methods of measuring with such high degrees of precision?

Re: FAA issues emergency directive on 2,000 Boeing 737 NG, Classic planes

#9
post #7

One of the inspection checklist items: Measure the clearance between the flapper bushings at both locations on each engine bleed air 5th stage check valve. If the clearance between the flapper bushings is a minimum of 0.004 inch (0.102 mm) at both locations, the engine bleed air 5th stage check valve at that location has passed this inspection. I knew that aviation engineering dealt with tight tolerances, but boy, it…

I supposed they'd be using something like this: https://en.m.wikipedia.org/wiki/Micrometre

Re: FAA issues emergency directive on 2,000 Boeing 737 NG, Classic planes

#10
post #7

One of the inspection checklist items: Measure the clearance between the flapper bushings at both locations on each engine bleed air 5th stage check valve. If the clearance between the flapper bushings is a minimum of 0.004 inch (0.102 mm) at both locations, the engine bleed air 5th stage check valve at that location has passed this inspection. I knew that aviation engineering dealt with tight tolerances, but boy, it…

Is that just being able to slide a piece of thick paper into the gap?
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