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(PDF) Irish report for United 757 incident on approach to Dublin

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While descending in or near turbulence, first officer airspeed became unreliable. FO twice initiated a high altitude stall recovery, which led to injuries and aircraft damage, before the captain took over with an operable airspeed indicator. (www.aaiu.ie) Ещё...

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Highflyer1950
Highflyer1950 4
Wow, descending into an area of heavy precipitation I assume at a normal speed and rate of descent and the 5000 hr FO sees 90 kts and says we are stalling! let's not check the other "two" airspeed indicators or the AOA or pitch attitude and power setting but pitch it over and add full power.Not once but twice! Not necessarily a bad thing to do, but just think if all the copilots' instruments went blank or read erroneously, wouldn't you just look over at the standy and Captains instruments for verification? I have had the displays go blank, and have seen a lot of St. Elmos fire.....it looks pretty cool. Again I applaud quick thinking but only when it's backed up by reality. Anyone remember the scan technique? Now we get to look at one bloody display and when it goes wonky the worldis upside down, but is it really? Glad there were no really serious injuries.
karl
Karl Lehenbauer 1
Yeah I read a fair bit of the report. The FO doesn't look super good insofar as not telling the Captain what he was doing, misinterpreting the overspeed warning horn as a stall warning (confirmation bias), not pulling the CVR breaker after the incident, etc.

If I understood what I read, though, there was an automation issue, like the software check for a discrepancy between the Captain and FO's IAS is only performed once every 64 seconds and the timing of that meant the crew may never have been shown an indicator related to that. It also said originally on the 757 there was no IAS discrepancy check but there were multiple incidents/crashes due to this sort of malfunction so they added that. If the EICAS had thrown a caution and indicated the discrepancy before the FO saw the super low indicated airspeed and reacted then the incident probably wouldn't have occurred.
Highflyer1950
Highflyer1950 1
Interestingly, while increasing the airspeed to 30 to 40 above VNE and subsequently entering moderate to severe turbulence, pushing and pulling probably overstressed the area where the hydraulic/plumbing inspection panels were located and the pax/crew injuries were copilot induced.
Cloudfish
Cloudfish 2
A similar thing happened to me one time, many moons ago. I was an FO on a King Air 90 with steam gauges, and the Captain was flying. I was calling out the numbers as we were climbing out, when all of a sudden my airspeed indicator started dropping. It slowly dropped from about 140 to 80 in a matter of about 6 or 7 seconds, and I was calling out the numbers in increments of 10. At 90 I became concerned, and at 80 my instinct was to reach up and push the yoke. I looked over simultaneously as my hands started moving, and immediately noticed that the left indicator was still at 140. Afterwards the Captain commended me for both reacting and for cross checking. Turns out that the nut for the pitot/static drain system (which is on the right side panel near your feet) had come loose and had created a leak in the right side system.
Flightdog
Roger Curtiss 1
It is easy to second guess after the fact, however, there appears to have been a rather serious lack of CRM and communication. The CAPT believes the rapid descent was due to turbulence and the FO continues to rely on his IAS indication even after the CAPT informs him that his and the standby indications are in agreement.
jbqwik
jbqwik 1
In the decades before digital engine controllers (automotive) most problems were mechanical, most people could understand and even fix them. Nowadays we open the hood of our cars, look at miles of plastic, shrug, close the hood.
It seems to me something similar is happening in commercial aviation, at least the training and experience end of it. IOW, too much silicon is doing too much of the thinking, which leads to over-reliance, apathy, and a general lack of involvement.
Then, again, without being there it's easy for me to armchair my comments. Glad this ended well.
karl
Karl Lehenbauer 1
I don't know if you are implying it but I think it's safe to say a large majority of pilots prefer glass to the old analog instruments. Your situational awareness is so much better with glass both from the presentation and the automation, and the mechanical instruments malfunctioned and at much higher rate than the modern ones.

As to cars, yes they aren't as simple as they used to be, but they're not that bad... fuel pump, filter, regulator, rails, injectors... air cleaner, throttle body, plenum... MAP/MAF sensor, O2 sensors. The OBD II usually gives you a pretty good idea where to look. Carbureted engines with mechanical distributors were simpler but quite a bit less efficient, more pollute-y and needed more frequent maintenance (plugs, points, condenser, etc). The ethanol in modern US gas is hard on carbs, too.
jbqwik
jbqwik 4
you sure nailed me: old school, I am <grin>
I agree with you, the awareness is enhanced. but i question if the average modern aviator commands all that goodness?
bkoskie
Billy Koskie 1
With current car technology, if you are willing to invest $3-400 in an OBDII scanner, the car will tell you what is wrong with it and will suggest items to inspect/repair.

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