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(...)Ok, you are not wrong- but you were overly dismissive of the real safety benefit of a two person crew. Not REQUIRED*, but very very very very very very nice to have!!!!!!!!!!!!!!!!(...)
Hmmmmm... which is exactly what I wanted to say with my post. I just didn't do it in these emphatic terms. You only NEED one person to fly a plane (almost all of the time). That doesn't mean, however, that I consider the second pilot a luxury.
As for single-pilot military ops, it would be interesting to learn something about accidents caused by pilot incapacitation (through something else other than enemy action). But I guess that's a topic for a different thread...
Hmmmmm... which is exactly what I wanted to say with my post. I just didn't do it in these emphatic terms. You only NEED one person to fly a plane (almost all of the time). That doesn't mean, however, that I consider the second pilot a luxury.
"Exactly" what you "wanted" to say is not what you actually said and it wasn't that you lacked "emphasis" but instead had significant factual oversight.
Paraphrased: "They are there as a backup and to keep us comfortable in the back".
That's somewhat dismissive of reality where the second pilot performs critical tasks of radio communication and operation, navigation, numerous active safety checks, fuel and other systems management and active monitoring of the flight.
That's somewhat more than sitting there as a backup and adjusting the cabin temperature.
Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.
There were no flaws in their navigation... they got the plane all the way from South Korea to being lined up with the runway at SFO with no issue (at least none indicated in the report).
Likewise, no flaws in their communication (in the sense of communication with the outside world) were identified. They made all required radio calls, and seemingly received and understood all incoming transmissions.
Which leaves... aviation. Do you disagree that slamming a perfectly good airplane into a seawall during a landing attempt in almost perfect conditions is poor aviating?
There were no flaws in their navigation... they got the plane all the way from South Korea to being lined up with the runway at SFO with no issue (at least none indicated in the report).
Well, no flaws in the lateral sense, but there might have been at least one instance of being 100 feet on the low side...
Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.
As a result [of using FLCH SPD without speedbrake], the airplane started to drift above the desired glidepath. In addition , the PF did not appear to promptly recognize that the airplane was drifting above the desired glidepath after he had selected a lower airspeed in FLCH SPD .
Likewise, no flaws in their communication...
11:16:50.3
APR
Asiana two one four heavy descend and maintain
niner thousand contact approach one three five
point sixty five good day.
11:16:57.7
RDO-1
ah descend nine thousand one two five six five
Asiana two one four good day.
10:55:42.2
CTR
Asiana two fourteen descend pilots discretion
maintain flight level two four zero.
10:55:47.4
UNK
(confirm Asiana two zero two.)
But I was referring more to flaws in inter-cockpit communication. Many of those.
That crash is an excellent example of failure to aviate first while navigating and communicating quite well.
Originally posted by Evan
But look at this transmission and that transmission....
Evan's in his black and white procedural world where there's no place for airmanship fundamentals and just can't comprehend that the Asiana plane crashed because the pilots skipped the very basic step of monitoring airspeed on short final...just like Gabriel used to do in his complex Tommahawk...
It crashed because of the communication issues Evan mentioned mentioned...Elaw and I stand corrected.
And for the record, "quite well" is not an absolute, black-and-white term, it does allow for imperfections.
Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.
Joint Malian / French Press Conference August 7 2014
N'Faly Cissé, President of the Investigation Commission of the Republic of Mali, and Rémi Jouty, Managing Director of French BEA delivered a Press Conference today
Les experts du BEA ont donné une conférence de presse ce jeudi 7 août, pour établir les premiers éléments d'informations quant au crash de l'avion AH5017 d'A...
Key excerpt from conference :
The investigation is carried under responsibility of the Republic of Mali, as state where the crash occurred, with the technical assistance of French BEA. It involves cooperation of authorities from Algeria, Burkina Faso, France, Mali, Spain and United States.
Three international task forces have been setup :
1) Aircraft group focusing on the recollection and analysis of debris and the reconstitution of the last moments of flight
2) Systems group focusing on the history of flight and trajectory
3) Operations group focusing on weather and ATC data
The data from FDR have been analyzed to recreate the flight trajectory. The scenario remains to be substantiated by aircraft performance analysis to be conducted with the support of Aircraft manufacturer.
The CVR is magnetic tape type, and has been damaged during the crash. The tape itself severed during the crash, has had to be been repaired by BEA experts. Unfortunately, there is no conversation to be heard on the tape. It seems that, prior of the crash, the CVR was not recording or malfunctioning. BEA will further analyze the tape, but there is no guarantee that information can be retrieved.
Satellite infra-red pictures at the time of the flight show clouds with considerable vertical extension, above flight level. The picture shown during the briefing symbolizes the top of clouds, and not necessarily the extension of clouds at lower levels.
The sequence and trajectory of flight have been reconstructed as follows :
- 01:15Z : AH5017 departs from Ouadagoudou Airport.
- During climb, and early cruise, the aircraft flies a mostly northerly route, with limited course deviations, consistent with crew maneuvers to avoid thunderstorm cells
- 01:37Z : Aircraft reaches its cruise level of FL310, and speed stabilizes at 273 kt / M0.74.
- Two minutes after Top of Climb, aircraft speed becomes to decrease smoothly, while flight is maintained level at FL310.
- At 01:45Z : altitude becomes to decrease, speed being down to 200 Kt. Speed decreases subsequently down to 160 Kt. The aircraft enters a sharp left turn, with altitude dropping rapidly, and abrupt changes in pitch and roll.
- The aircraft descent in left spiraling turns
- The last recording takes place at 01:47:15, at an altitude of 1600ft and speed of 380 kt. The lapse time between the last recording and the impact is estimated to be one second.
- The aircraft hits the ground with high vertical velocity, and is destroyed. There is no evidence that any part of the aircraft disintegrated in flight before impact
Handout of the conference can be downloaded here (unfortunately, the .pdf size exceeds the forum limit)
Lisez Crash Air Algérie - Présentation du BEA en Document sur YouScribeInformation du 7 août 2014 sur le vol MD83diffusée avec l’accord du Président de la Commission d’enquête du Mali.Livre numérique en Actualité et débat de société
In a nutshell, the plane reached cruise level and started to slow down despite the autothrottle adding power to the max EPR it will command.
At the same time, the autpilot kept increasing nose-up elevator and trim to raise the nose and keep the selected altitude as the speed was diminishing. The FDR contains AoA information but it has not being decoded yet (there are uncertainties regarding the decoding function). But an increase in pitch with constant altitude means increase in AoA.
When the plane started to descend, the airplane had 10° of nose-up pitch. Regardless the descent, the nose-up elevator and trim kept increasing (and hence the AoA too).
Eventually, the airplane lost bank and pitch control and entered a spiral dive. At about the same time, the engines' parameters started to fluctuate. For me this likely means that the plane stalled or at least the AoA was too high, which in low-wing, rear-mounted engines airplanes can disturb the airflow to the engines, and also reduces the bank stability, control and damping.
The plane crashed almost vertically and at a very high speed.
It looks like another "Pinnacle" case. ("Grab a diet Pepsi and let's four-one-oh it"), except that the altitude they were holding, 31000ft, seems easily achievable and sustainable, at least under normal conditions.
So now it's time to think what abnormal conditions could have been present.
The report does mention weather, thunderstorms, clouds, icing, temperatures and the famous ITCZ (intertropical convergence zone).
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
In a nutshell, the plane reached cruise level and started to slow down despite the autothrottle adding power to the max EPR it will command.
So now it's time to think what abnormal conditions could have been present.
The report does mention weather, thunderstorms, clouds, icing, temperatures and the famous ITCZ (intertropical convergence zone).
Wow, both engines are experiencing almost simultaneous anomalies. It certainly seems like an environmental issue. Rain, hail or ice ingestion, or ice accretion? It looks like at around 1:38:00 there is a fairly subtle event, maybe a developing rotating stall due to ice accretion that reduces the engine outputs and then develops suddenly at 1:45:00 into a full on compressor surge of both engines. Did the ITCZ strike again?
In any case, it also seems to be another case of not flying the plane, which continues to be the real problem up there. And the captain has over 10,000 hours on type!
I wish there were FDR plots for engine vibration and TLA. And ice-protection.
I suppose another possibility is that there were ingestion-related surges at 1:38:00 and the crew did not sufficently reduce power setting (and altitude), leading to a catastrophic failure at 1:45:00. The EGT plot looks a lot like flameout doesn't it?
Wow, both engines are experiencing almost simultaneous anomalies. It certainly seems like an environmental issue. Rain, hail or ice ingestion, or ice accretion?...
I suppose another possibility is that there were ingestion-related surges at 1:38:00 ...
1- Compare EPR vs N1, N2 and fuel flow.
2- Look at picture of the engine in page 19.
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
If the problem appears to be with the engines, what about something wrong with the fuel. Not running out, but some kind of contamination which could cause either the loss of engine power or engine flame out.
1- Compare EPR vs N1, N2 and fuel flow.
2- Look at picture of the engine in page 19.
Are you implying the EPR indication is erroneous, possibly due to icing?
I haven't read the whole report, but my understanding is airspeed decayed in spite of "Otto" applying increasing throttle. That would point to an issue other than an instrumentation problem.
OTOH I think the fuel controllers in those engines meter the fuel based in part on the pressure reading at the engine inlet. If that's the case and the controller were getting an incorrect pressure reading, it's possible it could have reduced the fuel flow to the engine in spite of the throttle setting increasing. But I'd think in that case you'd see a reduction in N1, not just EPR.
1- Compare EPR vs N1, N2 and fuel flow.
2- Look at picture of the engine in page 19.
Yes, it can't be. Air Florida Flt 90 on automatics?
ITCZ phenomonena ice contaminating the PT2 sensor at altitude / The AT reverting to MACH ATL when the mach target wants to add thrust and the EPR limit has been reached, witholding thrust to respect the EPR limit / So N1 and fuel flow decrease but EPR continues to rise...
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