azflyer wrote: ↑Sun Aug 08, 2021 5:37 am
Lem,
The in depth investigation by the FAA let the weasel words stand, and allowed them to be added to the CAB report?
In my experience working in Aerospace, yes. In my interactions with government agencies, and in writing reports concerning failures, the wording that is used is chosen VERY carefully and there is much hemming, hawing and hand-wringing that goes on.
Additionally, never underestimate the fact that in America, bureaucratic organizations are in some ways formed to keep commercial entities in existence. The companies support the bureaucracies, and the bureaucracies support the companies.
But that is just my experience in working in Aerospace and Defense on government contracts.
azflyer,
The issue regarding Lem's point is simply this: would it be a possible, legal, and safe to fly a Piper Navajo Chieftain PA 31 350 with sufficient fuel and three passengers on board, which aircraft had experienced an engine failure at 20,000 feet (your estimate) with no damage to the airframe, on a single engine from an approximate midway point between SLC and St. George, to either airport.
As shown upthread, this aircraft is reported capable of not only maintaining altitude on one engine, but of climbing at 250 ft. / minute on one engine (at sea level at maximum gross takeoff weight). Since there is no terrain anywhere near 20,000 feet (or even 10,000 feet) between SLC and St. George, the aircraft would need only be capable of maintaining an altitude of say 9,000 feet (in case pressurization was lost) on one engine during the flight to either destination*.
The manufacturer and the US Department of Transportation (in this case the FAA) agree that this aircraft has been demonstrated and certified capable of maintaining cruising altitude on a single engine. This determination has nothing to do with the amount of damage to the affected engine, so long as there was no damage to the airframe from the failure.
So the language in the report regarding the ability to continue flight to either station was not weasel words, but a statement of fact in accordance with regulations. The report did not state that continued flight was the safest or most prudent course of action, but that the aircraft was capable of continued flight. The most prudent course of action was the precautionary landing at Delta Municipal.
In working at a national laboratory on DOE and DOD contracts, including with aerospace and defense companies like Sikorsky Helicopter, Pratt & Whitney, General Dynamics and others, in the US and overseas, I agree that there can be some discussion and even debate among stakeholders about the wording of project work products. The objective of the exercise is not to deceive, but to be even-handed and fair to both the client (in my case the US or foreign governments) and the manufacturer / supplier, when describing the outcome of tests or product evaluations. Human lives and hundreds of millions or billions of dollars are often at stake.
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* To be thorough, please note that Extended-range Twin-engine Operational Performance Standards (ETOPS) rules would not be violated by such a flight because the aircraft would always be (substantially) less than 60 minutes flying time from the nearest airport.
