A very worrying report indicates that airliners may be vulnerable to a clash of technologies that might "mask" dangerously low altitudes.
French investigation authority BEA believes the prevalence of ILS approaches has obscured an underlying vulnerability of aircraft to the risk of terrain collision arising from incorrect altimeter pressure settings.
BEA made the remarks following its inquiry into a serious incident in which an Airbus A320 descended to just 6ft above ground during a low-visibility approach to Paris Charles de Gaulle’s runway 27R.
The ILS was not operational on the day of the incident, 23 May 2022, and the Airhub aircraft (9H-EMU) was conducting a satellite-based approach with barometric vertical guidance.
But BEA found the pilots had set the altimeter reference to 1011mb instead of 1001mb, after being given an incorrect QNH pressure reading by an air traffic controller. This resulted in the jet’s flying a descent path which was 280ft below the required profile.
Although this triggered a minimum safe altitude warning in the control tower, the controller took 9s to inform the crew – by which time the jet was 122ft above ground – and then used incorrect phraseology. The crew did not hear this call, and continued to descend.
BEA says the approach lights had not been switched on, and heavy rain meant the windshield wipers were operating at maximum speed.
After passing what they believed to be the decision height – but with the jet actually much lower, just 52ft above ground – the pilots initiated a go-around, because they had no visual contact with the runway.
The aircraft descended to 6ft, while 0.9nm from the threshold, before climbing away.
There's more at the link.
That's frightening as hell to anyone who flies frequently. Basically, the aircrew entered an incorrect value, but did not double-check it; and then they relied on the aircraft's technology, now mislead by their entry, to keep them safe. It's only by the grace of God and a couple of seconds' leeway that they didn't fly their airliner straight into the ground, killing everyone aboard.
We're seeing this more and more; aircrew relying on technology to fly the plane rather than doing so themselves. Automation has become so advanced (?) and so complex that it's easier to simply set a computer to do what you want, then sit back and let the computer figure out how to do it. If incorrect values have been entered, and the computer uses them in its calculations, you have no way of knowing that the danger exists.
As another example of relying on technology rather than pilot skill and concentration, consider the crash of Asiana Airlines Flight 214 in 2013.
The Asiana pilots said in interviews with the National Transportation Safety Board that they had set the auto-throttles to maintain an air speed of 137 knots. That’s a significantly faster speed than the plane actually achieved as it came in for its landing at San Francisco International Airport on Saturday.
. . .
The pilots’ statements do not resolve the central question of why the Boeing 777’s speed and altitude fell so far out of the normal range for landing at SFO before it hit a sea wall and crash-landed. But outside air safety experts said the statements suggest a risky reliance on technology when the flight crew should have been constantly monitoring the airplane’s speed.
“Whether it was engaged or not working is almost irrelevant,” said Barry Schiff, a former TWA pilot and an air safety consultant. “The big mystery of Flight 214 is why in God’s name did these two pilots sit there and allow the air speed to get so low.”
Experts said the pilots should have been monitoring the plane’s speed every few seconds, and could have manually taken control of the engines at any time.
Again, more at the link.
The first report gives me the shivers. Six feet off the ground??? Oy gevalt . . .
Peter
15 comments:
I'm sorry, I don't understand. If it was already preparing to land, at that height, wouldn't it have just 'landed'? Sorry for dumb question.
The Air Traffic Controller gave the pilots the incorrect altimeter setting. If the pilots were doing their due diligence they would have noted by radar altimeter that they were too low but that would only been near the end of the approach. Also runway lights should have been on.
I speak as a professional pilot holding an ATP with over 4000 hours flight time.
In the first instance the pilots should have caught that the altimeter setting was drastically different from the atis and questioned it. Radar altimeter could also have caught it but is frequently ignored in the modern cockpit. It was human error not computer error
@Jen: It was that high when it was still nine-tenths of a mile from the runway. Landing on bare dirt . . . not such a good idea!
Ah, ok. Thank you.
There is a youtube video out there showing the cockpit view of an A380 landing in San Francisco. Through the whole approach they leave the autopilot on and change altitude/direction though it. At the last seconds the pilot takes control.
I've heard with Airbus there is a sort of policy that the pilot takes off and lands. Otherwise the computer should be in control of the flight.
Now imagine the fun and games when TPTB require automated control of all vehicle traffic.
More than likely the gear had not been extended yet because the crew were anticipating that they were still on approach.
No. Gear would be extended prior to intercepting glidepath, and starting the descent, but without a flare the touchdown would have been hard.
I used to calibrate airspeed & rate-of-climb indicators. I triple-checked EVERYTHING. If I make a mistake in calibrating a micrometer, some expensive tooling might get wrecked. Mess up aircraft instruments and people die. Not only that, the FAA will be checking every step those instruments ever journeyed, and people go to prison.
--Tennessee Budd
The only thing more frightening to me than two lazy minds in the cockpit is the expectation of another round of "suggestion" that the number be reduced to one.
During WWII, that was one of the major reasons the Lancaster bomber had a high loss rate.
Jonathan
This is just one more reason why the wife and I rarely fly anymore, even though her job requires across the country travel a couple times a year. We now have an RV and manage our own travel, thank God!
My hobby drone has collision avoidance - How in the heck does a COMMERCIAL PASSENGER JET not have something similar to prevent exactly this sort of scenario? If they do, how come it didn't work here?
First rule of flying airplanes, fly the damn plane. All that modern technology is there to assist, not to do your job for you. Trust your instruments but cross check with redundant and diverse indicators Spoken as a former nuclear reactor operator.
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