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Just posted to the Cirrus Owner's site...


FastEddieB

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Eddie,

 

Its a simple argument, not a lot has to be said. Thought provoking, I have done the retraction that I mentioned above many times and when done in the Skyhawk I never reacted but when I do the same in my CT the hairs on the back of my neck stand up a bit. I think its because the flap change in the CT is far more disruptive than in the more stable Skyhawk.

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I agree flap changes in the CT are more attention-getting than in most aircraft. When I hit the flaps on downwind, aside from the significant pitch change, it also feels like hitting the brakes and it slows down very fast...there is a lot going on there. Also when retracting them I get more of a 'sink' feeling in my gut from the lift change than in other planes, especially from 15° to 0° on takeoff.

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I agree that at first flap deployment in a CT has some pitch affect, but after a bit one can get pretty smooth at it. My objective is to make it unnoticeable. I'm not there all the time but sometimes I can do it, and I know a CT pilot who is smoother at it than I am. I have to say that I think things like smoothing out the flap deployment pitch goes a long way to make a naive passenger confident and comfortable.

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Not yet, but I'm working on it. When I close the throttle there is significant left rudder required and obviously the flaps cause a pitch change. Sometimes I'm a little ahead of these changes, sometimes a little behind. But there is a lot less movement than when I started flying the CT. Throttle changes is particular take a good bit of rudder correction in the CT, which is unlike other airplanes I have flown. I think (hope) it's making me a better pilot.

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I agree that at first flap deployment in a CT has some pitch affect, but after a bit one can get pretty smooth at it. My objective is to make it unnoticeable. I'm not there all the time but sometimes I can do it, and I know a CT pilot who is smoother at it than I am. I have to say that I think things like smoothing out the flap deployment pitch goes a long way to make a naive passenger confident and comfortable.

 

Absolutely.

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Not related to when to deploy flaps...

 

Comments on COPA have wondered why the pilot could not have retracted/deployed the "good" flap, resulting in a stable aircraft.

 

I posted this:

 

"I think CAPS is the more conservative choice here.

 

Why? You have a flap in an unknown condition.

 

One can imagine going flaps up and having an apparently controllable plane. But then having a different relative wind on landing "catch" that wonky flap and reposition it, possibly while flaring.

 

Kind of like the first Cirrus fatal, the one with the test pilot and a binding aileron instead. The plane was controllable enough in flight to get it down to the runway, but there the dynamics changed - with fatal results."

 

For those unfamiliar, the NTSB report on that first Cirrus fatal is here: http://www.ntsb.gov/aviationquery/brief2.aspx?ev_id=20001205X00274&ntsbno=CHI99FA112&akey=1

 

I have no chute, so would have to try to figure out a way to get down one way or another. If I had a chute, a wonky flap, aileron, elevator or rudder would have me thinking long and hard about a pull.

 

But That's Just Me!™

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With permission from Rick Beach, his additional narrative of the YouTube video events:

 

Sequence begins with pilot flying downwind for Chandler Airport at Alexandria, putting in 50% flaps and beginning base turn. Note that the plane seems to resist turning left. Then a brief return of flaps to 0% and back to 50%, then a pronounced right turn -- exactly the wrong direction for the base leg. As the plane struggles with control, the pilot attempts flaps 100% and the plane really goes right and rolls to 86 degrees, the stall warning horn goes off and the pilot pulls the CAPS handle.

Height of the CAPS activation is 2045' pressure altitude, which is about 620' above the airport and 660' above the frozen lake.

So, pretty amazing that the CAPS activation was successful when in an 86 degree bank less than 1000' above the ground.

 

 

Some additional narrative looking closely at the sequence of data samples just prior to and following the CAPS activation:

  • Prior to activation in level flight, pressure altitude was about 1800' and GPS altitude about 2000', a difference of 200 feet, airspeed was about 100 KIAS, and attitude was pitch level and roll changing from left to right bank (data records only plane attitude, not control inputs, but that's the wrong way to turn base to final)
  • Plane begins a climb with full power to a maximum altitude of 2095' pressure altitude or 2275' GPS altitude, but roll increases to 86 degrees right wing low at an airspeed of about 90 KIAS
  • Stall warning occurs at airspeed of 94 KIAS (note really high airspeed while plane is on knife edge),2045' pressure altitude or 2198' GPS altitude, pitch of negative 12 degrees and roll of 86 degrees, and downward acceleration of 2.5 Gs (plane is falling out of the sky!!)
  • CAPS pull recorded two seconds after stall warning with plane in similar attitude
  • CAPS pull occurs at 1941' pressure altitude or 2042' GPS altitude, a difference that now is only 100 feet (maybe GPS antenna works differently when pointing to horizon rather than sky!)
  • CAPS pull was approximately 813' AGL pressure altitude or 680' AGL using GPS altitude (odd difference of 150 feet now, go figure)
  • At 6 seconds after activation, a pitch up to 26 degrees with roll angle decreasing to 50 degrees
  • Plane rolls level after 15 seconds after losing over 500' altitude
  • Plane impacts the ground after 20 seconds while pitched down 20 degrees and banked left 20 degrees
  • Landing site shows altitude of 1127' pressure altitude or 1360' GPS altitude

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I'm getting in a little late in this discussion but there is a big difference between lowering flaps in a 737 and the CT. The 737 has an automatic response to split flaps in that it will stop all flap extension if it notices a "split" flap condition. This will occur well before serious control issues.

 

Without this split flap protection in a small airplane, a flap failure can be more problematic therefore it all boils down to "know your aircraft" and fly it according to your abilities.

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That's interesting to know about split flap protection on airliners. On the little planes I flew, Citations and King Airs and C401/2, there was none of that and we routinely deployed flaps in a turn. I wonder at what level of sophistication the split flap protection is found or mandated? I wonder if it is in the RJs and other feeder airlines planes?

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