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Post by maverick on Nov 20, 2020 12:13:46 GMT 1
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Post by dereks on Nov 20, 2020 15:17:12 GMT 1
I think to summarise - nose wheel system failure on landing - In reacting to this left rudder was applied to counteract the planes movement to the right - but at the same time the captain was inadvertently applying RHS braking - so when the speed dropped to a point where airflow over the rudder was not sufficient, all that was happening was that the RHS braking steered the aircraft further right and onto the grass.
I would say all this happened in a very very short space of time and I wouldn't think it fair to be critical of the pilots actions.
Dereks
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Post by northbynorthwest on Nov 20, 2020 18:39:41 GMT 1
Yes, Derek summarized it pretty well. Couple of things I would add are that the crew were not trained on dealing with losing nose gear steering, and that this is now required training for the company. Furthermore, the aircraft Quick Reference Handbook (QRH) and Aircraft Flight Manual (AFM) produced by the manufacturer, have been revamped so that the sections on how to handle situations when nose gear steering failure have been improved. This was a moot point for this flight, as you use these manuals when you have a known issue. Here, the crew didn't know they had an issue until the nose gear touched down and the EICAS message for nose gear steering fail came up on one of the CRT screens. By that point, the aircraft had passed Foxtrot; so everything happened from that point until exiting the runway just before Echo. That is maybe 1500ft, just a few seconds.
As Derek says, directional stability is normally maintained by use of the rudder pedals until speed drops to a point where the rudder loses effectiveness due lack of airflow around it. At that point, directional stability is maintained by differential braking until the speed is such that the captain can steer using the tiller to taxy off the runway and to parking. With this situation, the nose gear was apparently castoring so that as the rudder became ineffective, the aircraft would move in the direction that the nosewheel had castored to....in this case to the right. So the captain tried to use the left rudder pedal to maintain control, but could not prevent it coming off the runway. I can see the right brake being applied lightly at the same time as the left rudder being applied as just a natural reaction to a rapidly developing situation. You plant your foot on the left rudder pedal firmly, and could well apply some pressure with the other foot without realizing it.
Many years ago as a fairly new Flight Dispatcher at Northwest Airlines, I had a DC9 heading from Minneapolis to Minot, North Dakota who called on the radio for myself and the maintenance coordinator to discuss a warning light regarding nose gear steering as he was descending into Minot. No EICAS messages spelling out what the problem was in those days, just warning lights and annunciators. Anyway, Minot had a short runway with snow and ice, and no real maintenance available - so a simple decision to return to Minneapolis, with long and wide runways with no snow, good weather and no crosswinds. Enroute we all reviewed the manuals, and the procedure was simply to turn off the nose gear steering switch, which would allow the nose gear to caster - and to use differential braking to maintain directional control on landing. We had the fire trucks out, and maintenance would tow the aircraft off the runway. It had not in fact failed, but was a faulty warning light. No big deal when you know about it in advance and have time to review the QRH and the non standard procedures in the AFM, which spell out step by step exactly what is to be done to deal with each and every situation. This crew at Liverpool didn't have that luxury. Nor did the crews of the two 737 Max crashes, but that is totally another story.
As usual, I have probably gone into way too much detail here, but I hope it is not too geeky.
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Post by bulldog on Nov 20, 2020 20:04:18 GMT 1
With reference to this failure of nose wheel steering I had the same event happen to me personally. A few years ago i had hired a Cessna 172 from Kissimmee, Florida for some flying while on holiday. Now not sure if anyone else has hired aircraft in Florida but in my experience while they are cheap omg they are junk. First one vacuum pump failure, then in a separate incident with a PA28 from Winter Haven DI failure. This was another incident. So off I went with a friend from Kissimmee,stopped somewhere for a coke as there are no landing fees which is great fun. Then we thought off to Daytona. Landed no problem, slowed, then the aircraft turned slowly to the right and ended up off the right side of the runway. We had lost all directional control from the nose wheel.
We got out and walked over to some hangars , found an engineer who put us in his Dodge Ram pick up and drove over to the stranded aircraft. He had brought a Cessna towbar, this was attached to the nose wheel, he unfolded the tailgate , which we sat on holding the towbar and towed the 172 over to the hangar. The engineer got inside, lifted the carpet and found a bolt had come out of the linkages and stuff down there. He put it back in , charged us I think $25, and off we went. No paperwork, nothing. Flew back to Kissimmee , they simply thanked us, and knocked the $25 off the hire charge. No paperwork, don't think they even had a look. No firetrucks for us!! Could you imagine the fuss if you got out of an aircraft on a UK airfield and walked across a taxiway to get to a hanger.
CAA would have a panic attack, then allowing a random engineer to just pop a bolt back in with no checks.
Happy days flying over there. Another incident at winter Haven was being told to fill one wing with Mogas, the other with Avgas. The reason, Mogas was a few dollars a tankful cheaper. The fact it gave less power was seemingly unimportant !!!
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Post by ronturner on Nov 21, 2020 7:25:54 GMT 1
Good stories, Bulldog, and it reminds us of how relaxing it is to fly in the USA. In spite of your stories, which are somewhat typical I must say, it remains a fact that the safety record on flying under the FFA is better by a good margin than the stats brought about by the EASA system of bureaucracy over engineering and common sense.
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