Dash 8 gear problems ( Merged)
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Some people learn from experience.... some never learn.
Some background info on the Q400. Big props and an even bigger engine. Single engine it's fine to fly. Probably better than it is on two.....BUT.....it does increse pilot-flying workload because it has a two axis autopilot. ANY power change results in a rudder trim change. So most of your attention is gone just keeping the bloody thing in trim. Because of the two axis autopilot the approach has to be hand flown. Again, increase in workload, even if it is just following the flight director. The approach and landing has to be Flap 15 rather than 35 to meet performance criteria in case of a go-around and the extra drag isn't really needed any way. In the last stages of the approach the aircraft sits about 4-5 degrees nose up and we get a tail strike warning after 6. So you can't flare or arrest the descent with an increase in pitch or you'll bang the tail - every flap 15 I've had the 'pleasure' of being a part of has been a serious thumper.
So, back to our little scenario. You want to fly an aircraft, that has a dodgy main leg, and complicate it by flying a hand-flown single engine approach, which will result in a very firm landing. Fair enough.
And whoes to say that the prop won't still penetrate the fuselage even if it's 'stopped'? I'm sure Bombardier would have let us know that that was the recommended technique.
..........but what do I know?
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Sparkies,
Can you give us more info? Interesting since the Danish Accident Investigation Board clearly states in the preliminary statement:
"Examination of the internal threads of the retraction/extension actuator piston revealed the presence of corrosion, which led to separation of the rod end from the piston. The separation contributed to the landing gear collapse."
Can you give us more info? Interesting since the Danish Accident Investigation Board clearly states in the preliminary statement:
"Examination of the internal threads of the retraction/extension actuator piston revealed the presence of corrosion, which led to separation of the rod end from the piston. The separation contributed to the landing gear collapse."
I don't think the Q400 is quite as bad as speed freek makes out.
When I was at Flybe one of the training captains had the deck angles at which a tail strike would happen - if I remember rightly produced by Bombardier for the accident investigation concerning a tail strike SAS had in the very early days of operating the aircraft. The worst was about 7.5 degrees, but required full oleo compression and maximum tyre squash and ranged up to 12.5 degrees with oleos fully extended. These were actually higher than the attitudes for the dash 8 300 series, which was why the 6 degree warning doesn't appear in the Q400 like it used to in the 300. We used to do all our landings flap 15 unless it was what Flybe called a "short runway" when Flap 35 was mandated - and a gentle flare to about 6.5 degrees nose up gave consistantly smooth landings with a little practice.
Fortunately I never had to fly a real SE approach, but several TREs allowed me to try it in the sim when we had spare time and the autopilot was quite capable of doing it - once the engine is shut down and feathered and the approach stabilised the power changes and thus yaw resulting are minimal and easily compensated for by the rudder trim. I was told that the only reason for not using the A/P on SE approaches was that Bombardier were scared of possible law suits if something went wrong. I was also told that SAS had an SOP to use it despite what Bombardier said, and that the Swedish CAA was happy about that - however that may just have been heresay.
Whether you would intentionally shut an engine down in these circumstances is probably a question of personal preference which is open to debate, but it appears that one of these crews didn't - and there were injuries as a result of the prop disintegrating, and one crew did, and there weren't.
When I was at Flybe one of the training captains had the deck angles at which a tail strike would happen - if I remember rightly produced by Bombardier for the accident investigation concerning a tail strike SAS had in the very early days of operating the aircraft. The worst was about 7.5 degrees, but required full oleo compression and maximum tyre squash and ranged up to 12.5 degrees with oleos fully extended. These were actually higher than the attitudes for the dash 8 300 series, which was why the 6 degree warning doesn't appear in the Q400 like it used to in the 300. We used to do all our landings flap 15 unless it was what Flybe called a "short runway" when Flap 35 was mandated - and a gentle flare to about 6.5 degrees nose up gave consistantly smooth landings with a little practice.
Fortunately I never had to fly a real SE approach, but several TREs allowed me to try it in the sim when we had spare time and the autopilot was quite capable of doing it - once the engine is shut down and feathered and the approach stabilised the power changes and thus yaw resulting are minimal and easily compensated for by the rudder trim. I was told that the only reason for not using the A/P on SE approaches was that Bombardier were scared of possible law suits if something went wrong. I was also told that SAS had an SOP to use it despite what Bombardier said, and that the Swedish CAA was happy about that - however that may just have been heresay.
Whether you would intentionally shut an engine down in these circumstances is probably a question of personal preference which is open to debate, but it appears that one of these crews didn't - and there were injuries as a result of the prop disintegrating, and one crew did, and there weren't.
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I can echo excrab's comments about pitch and flap 15 landings on the 400 - not a problem, unlike the uncomfortable approach and carrier-style Flap 35 landing technique that some Flybe trainers (the newer ones) seem to teach!
Speed freak - if you feel your rate of descent is a little too high just add a tiny squeeze of power in the flare to slow the descent rate, and I mean tiny, literally around 1cm of power lever movement. Alternatively, just be a few knots over Vref.
Speed freak - if you feel your rate of descent is a little too high just add a tiny squeeze of power in the flare to slow the descent rate, and I mean tiny, literally around 1cm of power lever movement. Alternatively, just be a few knots over Vref.
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I was told that the only reason for not using the A/P on SE approaches was that Bombardier were scared of possible law suits if something went wrong.
Regards, MAX
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The autopilots on the Q300 and Q400 are simply not certified for single-engine operation (which is a pity as it adds quite some workload when things are sh*tty anyway).
I personally doubt that the Q400 autopilot can fly a single-engine approach without any difficulties as the Q400 requires rudder trim changes for any power change and the autopilot simply cannot trim the rudder. Maybe already posted somewhere here, but it really is a pity that Bombardier/Sextant did not add some kind of auto-trim for power changes or a powerful yaw damper. AFAIK even WW2 Messerschmitts had something like that.....
I personally doubt that the Q400 autopilot can fly a single-engine approach without any difficulties as the Q400 requires rudder trim changes for any power change and the autopilot simply cannot trim the rudder. Maybe already posted somewhere here, but it really is a pity that Bombardier/Sextant did not add some kind of auto-trim for power changes or a powerful yaw damper. AFAIK even WW2 Messerschmitts had something like that.....
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Tyrolean's Q400s are returning to ops one by one, most already back on the line. (There was no complete ban here, just for the high-cycle A/C as per Bombardier advice.)
The autopilots on the Q300 and Q400 are simply not certified for single-engine operation (which is a pity as it adds quite some workload when things are sh*tty anyway).
I personally doubt that the Q400 autopilot can fly a single-engine approach without any difficulties as the Q400 requires rudder trim changes for any power change and the autopilot simply cannot trim the rudder.
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just off the news:
unbelievable, but another -Q400 suffered nosegear failure on landing at EDDM this evening. (probably it was D-ADHA from LH-Regional member Augsburg Airways)
No injuries reported so far. I thought all 400s have been thoroughly checked
S (in german):
http://www.merkur-online.de/regionen...art8853,841192
unbelievable, but another -Q400 suffered nosegear failure on landing at EDDM this evening. (probably it was D-ADHA from LH-Regional member Augsburg Airways)
No injuries reported so far. I thought all 400s have been thoroughly checked
S (in german):
http://www.merkur-online.de/regionen...art8853,841192
Last edited by readywhenreaching; 21st Sep 2007 at 20:47.
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Originally Posted by readywhenreaching
I thought all 400s have been thoroughly checked
This is (yet another) nose wheel failure.
Sounds as if they should fit a ski under the fuselage, and no longer bother with the landing gear.
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I personally doubt that the Q400 autopilot can fly a single-engine approach without any difficulties as the Q400 requires rudder trim changes for any power change and the autopilot simply cannot trim the rudder. Maybe already posted somewhere here, but it really is a pity that Bombardier/Sextant did not add some kind of auto-trim for power changes or a powerful yaw damper. AFAIK even WW2 Messerschmitts had something like that.....
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DASH 8 incidents
Two accidents with SAS dash 8's, today one Lufthansa's Augsburg Airways, and two days ago one of FlyBe's aircraft could not raise the undercarriage so they had to do the whole flight the gear down. And all this has happened within a week. Scary!!!! I personally will not fly any airline that's using Dash 8-Q 400's......
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The Q400 is a typical modern design - under-built, fragile, and built to a price rather than a decent set of design criteria. No wonder they have had so many problems with it.
They might be great when they are shiny and new, but a few years from now I am sure that flybe will be very sorry indeed that they ever got involved with them.
They might climb reasonably well, but in every other department, they are a complete dog.
They might be great when they are shiny and new, but a few years from now I am sure that flybe will be very sorry indeed that they ever got involved with them.
They might climb reasonably well, but in every other department, they are a complete dog.