Have you done any flying since those days in Vietnam?

(Written on 2019年 03月 16日)(Permalink)

Introducing supplier quality into the discussion without indicating its relevance or warranty (since none is apparent) is at the very least, distracting and irritating. But claiming it to be causal to the accidents is just disrespectful to the 330+ souls that were unexpectedly and violently dissociated from their mission on Earth. I believe we owe them a verdict that is as accurate and valid as practical with fallible humans, not some arbitrary indictment of the nearest convenient entity by apathetic humans. (And in the same breath as an accusation of cutting corners?! Can you spell hypocrisy?

(Written on 2019年 03月 15日)(Permalink)

Probably not. Although a malfunctioning MCAS or one reacting to a failed AOA sensor can be effectively disabled by turning off the Electric Stab Trim system, I doubt a flight could be dispatched in that condition. Reason: I suspect MCAS contributes far more to safe flight than the mere “augmentation” of maneuvering characteristics as its name indicates. P.S.: Even after the nose-down commands from MCAS are rendered ineffective, the stick shaker function that it also activated will continue. So yeah, just blocking the nose-down commands won’t really bypass MCAS to allow normal scheduled operations without a nose-down risk. Note: Lion Air criticized the pilots on the Denpasar-Jakarta flight for flying with the Captain’s stick shaker active from takeoff to touchdown! But they also noted that none of the non-normal procedures the pilots executed on that flight included “Find a suitable place and land ASAP!” 🙄

(Written on 2019年 03月 12日)(Permalink)

Probably not. Although a malfunctioning MCAS or one reacting to a failed AOA sensor can be effectively disabled by turning off the Electric Stab Trim system, I doubt a flight could be dispatched in that condition. Reason: I suspect MCAS contributes far more to safe flight than the mere “augmentation” of maneuvering characteristics as its name indicates.

(Written on 2019年 03月 12日)(Permalink)

** MH124... The Lion Air failure and warning messages prior to the AOA sensor being replaced were an eclectic assortment that reminded me of Malaysian Airlines Flight MH124 on August 1, 2005. The 777-200 suffered an extended in-flight upset at 38,000 ft, with autopilot and autothrottle driving wild altitude excursions, with climb rate as high as 10,560 ft/min, large throttle changes, absurd warnings of simultaneous overspeed limit and stall speed limit, high g forces in all axes—a roller-coaster ride. The main problem: Corrupt x, y, z axis acceleration data from a known faulty accelerometer was output from the ADIRU as “valid.” The A/P and A/T reacted to that wildly fluctuating data, giving the passengers a thrill ride at 38,000 ft. AAIB Report: http://www.atsb.gov.au/publications/investigation_reports/2005/AAIR/pdf/aair200503722_001.pdf Replay of black box data: https://www.youtube.com/watch?v=1XNnEzFF5fg

(Written on 2019年 03月 12日)(Permalink)

I noticed something regarding the Lion Air AOA sensor in the Indonesian Preliminary Report... It had been removed & replaced at Denpasar—the Report indicated that the investigators had retrieved the original unit and would be examining it. I wouldn’t be surprised if that sensor turns out to be A-OK. Reason: The messages that preceded the sensor replacement were not the ones that indicate an AOA sensor failure.** The IAS DISAGREE and ALT DISAGREE messages only showed up AFTER the replacement, on the flight to Jakarta, and the accident flight. Per Boeing, those messages may appear due to an AOA sensor failure (though I can’t see why airspeed and altitude would become discrepant with an AOA sensor failure. ?!) So, although no AOA messages appeared on the flight deck, because AOA SIGNAL FAIL and AOA SIGNAL OUT OF RANGE got latched in the ADIRU (together with numerous other messages) on the previous two flights, in addition to other maintenance actions to deal with the reported events,

(Written on 2019年 03月 12日)(Permalink)

There are two instances of MCAS, the left gets data from the left AOA sensor and drives the Captain’s display and stickshaker, the other is for the F/O. Boeing indicates this in its list of flight deck effects that manifest due to an AOA sensor failure. Either MCAS instance will issue a pitch-down command to the FCC if it thinks a stall is imminent. The FCC then drives the Stab Trim nose-down.

(Written on 2019年 03月 12日)(Permalink)

?!? I’m nonplussed. How do you figure a pre-production test engine and one that is in revenue service are both “the same engine” design?

(Written on 2018年 08月 20日)(Permalink)

“No matter what steps Aviation takes forward, if safety is not increased that step will not be taken.” The implication of your statement is that safety must be improved with any change to the system. I have to disagree. While safety is paramount in aviation (and elevayors), there are other key performance metrics... availability, maintainability, utilization, environmental impact, etc., and if one or more can be improved without compromising safety, why would anyone complain?

(Written on 2018年 08月 14日)(Permalink)

Still, trillions of ETOPS flight hours have been flown ... : )

(Written on 2018年 06月 03日)(Permalink)