Close one at Frankfurt
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Super-strong winds around that time not that far from the airport that day. I saw building damage. Might have been doing the Beat The Thunderstorm game.
60 kts groundspeed at low altitude, and an over 1000 ft loss of altitude thereafter to regain speed does not sound great. No, stall not confirmed, but I would not confidently say “0” evidence either.
Rapid fluctuations in the 3D wind field can have nasty effects on the flight path.
QAR analysis may be able to quantify the vertical and horizontal windshears.
Shears can affect AoA
Bottom line: This windshear escape maneuver worked.
QAR analysis may be able to quantify the vertical and horizontal windshears.
Shears can affect AoA
Bottom line: This windshear escape maneuver worked.
Umm... that's QAR data in the avherald article showing a minimum 78kts IAS. Fairly certain that would put a 767 into the stall regime... so, a little more than an "assertion".
And yes, the escape manoeuvre did the trick. Good work.
And yes, the escape manoeuvre did the trick. Good work.
Yikes!
There is little indication of vertical vector of an outflow, there was an overshoot shear initially, seems more like a gross out of trim condition with the thrust pitch couple not being countered. Not pretty. The THS position will be of interest, the elevators position and control force applied would be telling. Not the first time, won't be the last.
There is little indication of vertical vector of an outflow, there was an overshoot shear initially, seems more like a gross out of trim condition with the thrust pitch couple not being countered. Not pretty. The THS position will be of interest, the elevators position and control force applied would be telling. Not the first time, won't be the last.
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Interim report out
There is an interim report (in German) at the BFU, page 17 of the pdf.
Wind shear escape, followed by a stall recovery.
https://www.bfu-web.de/DE/Publikatio...cationFile&v=2
My translation:
At 17:52:36 UTC, the flight crew lost visual reference to runway 25L at the decision height for the ILS approach and aborted the approach at an altitude of 684 ft AMSL. The pilot in command initiated a go-around. Shortly thereafter, a wind shear warning was issued in the cockpit. A wind shear escape maneuver was then flown, i.e. the pilot-in-command steered the aircraft into a climb and applied maximum engine thrust. At an altitude of 2,735 ft AMSL, at 17:53:19 UTC, the aircraft reached a pitch angle of +48 °, the angle of attack (AOA) at this time was +3.69 °, the airspeed was 117 kt IAS and the flaps were in the 20 ° position.
At 17:53:30 UTC, at an altitude of 2 843 ft AMSL, the stick shaker and the stall warning activated. The longitudinal pitch angle was +16° and the Angle of Attack reached +20.92°. The main landing gear was extended. The minimum indicated airspeed was 86 kt IAS and the minimum ground speed was 60 kt. Shortly thereafter, the flight crew temporarily lost control of the aircraft and descended at a rate that reached a maximum of minus 5 500 ft/min. According to the flight crew, the Stall Recovery Procedure was applied. The descent was terminated at 17:53:49 UTC at 1913 ft AMSL. The flight crew stabilized the attitude of the aircraft and the windshear warning had deactivated itself.
Wind shear escape, followed by a stall recovery.
https://www.bfu-web.de/DE/Publikatio...cationFile&v=2
My translation:
At 17:52:36 UTC, the flight crew lost visual reference to runway 25L at the decision height for the ILS approach and aborted the approach at an altitude of 684 ft AMSL. The pilot in command initiated a go-around. Shortly thereafter, a wind shear warning was issued in the cockpit. A wind shear escape maneuver was then flown, i.e. the pilot-in-command steered the aircraft into a climb and applied maximum engine thrust. At an altitude of 2,735 ft AMSL, at 17:53:19 UTC, the aircraft reached a pitch angle of +48 °, the angle of attack (AOA) at this time was +3.69 °, the airspeed was 117 kt IAS and the flaps were in the 20 ° position.
At 17:53:30 UTC, at an altitude of 2 843 ft AMSL, the stick shaker and the stall warning activated. The longitudinal pitch angle was +16° and the Angle of Attack reached +20.92°. The main landing gear was extended. The minimum indicated airspeed was 86 kt IAS and the minimum ground speed was 60 kt. Shortly thereafter, the flight crew temporarily lost control of the aircraft and descended at a rate that reached a maximum of minus 5 500 ft/min. According to the flight crew, the Stall Recovery Procedure was applied. The descent was terminated at 17:53:49 UTC at 1913 ft AMSL. The flight crew stabilized the attitude of the aircraft and the windshear warning had deactivated itself.
Do not change gear or flap configuration until wind shear is no longer a factor, straight from the operations manual. Severe wind shear may also exceed the capability of the AFDS. Interesting is that the flight deck crew had a combined 31,000 hours on the 767.
The jumpseat is often the best place to get an overview of what is happening and call it out. Most of us have fortunately only seen stuff like this in the sim and I am sure will have experienced the stick shaker in a windshear training scenario. Clearly pitch 48 is not great and what the flight director commanded would be interesting to know as well as aircraft weight. In monday morning quarter back mode the question I would ask is whether the captain taking control during the go-around was ideal.
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The statement of "Pitch 48 is not great" got me reading the report but look at the full sentence or two: At 2,735 ft AMSL, at 1753:19 UTC, the aircraft reached a pitch angle of +48° (pitch-up), the Angle of Attack (AOA) was +3.69° at the time, airspeed 117 kt IAS and flaps were in the 20° position. At 1753:30 UTC, at 2,843 ft AMSL, the Stick Shaker and the Stall Warning were active. The pitch angle was +16° and AOA reached +20.92°.
It seems to me that while it may have only been momentary, they were in a better position at a pitch of 48 degrees than when they were at 16 degrees.
From an weather point of view, on can see that three minutes before the large pitch excursions, the weather report was SA 20/06/2023 17:50 UTC METAR EDDF 201750Z AUTO 23013G31KT 9000 0650 R25R/P2000N R25C/P2000N R25L/P2000N R18/P2000N +TSGRRA BCFG BKN///CB. And, it had been pretty much clear skies prior t this.
Therefore, one might ask, what was the view like on the weather radar and out the window in the minutes leading up to this event. This may have been easily preventable by discontinuing the approach early with a 90 degree turn.