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In reply to:
IMO it sounds like another “hey ya’ll watch this!” accident.
Or just an overgross aircraft with an aft CG. Wouldn’t be the first accident where the pilot saw the trees coming and pulled. Could have just as easily been four guys in an Arrow.
Really, really sad.
It seems like far too little data to come to any hard conclusions. Of interest, however:
1)“Showing Off” - I’d want to know how interviews with prior passengers/fellow pilots go. Was there a pattern to this behavior? Or was the plane’s remaining “in ground effect” sound flying technique for accellerating to Vy?
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Taxiing with “both doors open” seem irrelevent. The observation that the flaps were in the “retract position” may or may not be significant. I run-uo and taxi with my flaps up and put them down (via checklist) right before takeoff. Hopefully the investigation be able to determine the position of the flaps prior to the crash.
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The report of the engine sputtering is interesting, but the “sputtering” sound could have been caused by the rotation of the aircraft causing the exhaust “profile” to change in a cyclical way.
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As a CFI, I would encourage pilots to ALWAYS do a run-up. Even after a full-stop and taxi-back. Admittedly, there may have been one here - witness accounts are always suspect.
Again, tragic, tragic, tragic. I hope we end up learning the cause so we can all learn from it.
Again, at the risk of reading too much into these reports… note that one witness described “2 or 3 turns to the left”. If this person meant full rotations, that would take a bit of altitude to get three complete spins in before hitting ground. That much altitude would suggest to me the “show off” theory…a low altitude run to gain speed for a steep angle take off. With four people on board, the rate of decreasing airspeed would be high…if he didn’t start pushing until he was at 70 or 80, or didn’t push aggressively enough, it’s easy to imagine slipping into a stall/spin. Also, a very aggressive push could create negative G’s and cause the engine to sputter, as one witness accounted.
Of course, that doesn’t mean he didn’t have a CG problem. I’m not so familiar with the Cirrus W&B tables…assuming no luggage and that the plane is not over gross, is it likely to be aft of CG with four equal size adults on board?
Why do you feel so strongly about ALWAYS doing a run up on every full stop and taxi back?
This was an SR-20, and it had 4 people in it. The report does not speculate as to how much fuel was on board, and doesn’t tell us estimated weights of the 4 passengers, but a new SR-20 G2 has a useful load of only 594 pounds with full fuel. My speculation would be one of an over-gross aircraft pulling off the ground, not climbing (“flying in ground effect”), and then doing an “Oh s–t! Here comes the trees” maneuver. Stall. Spin.
In reply to:
This was an SR-20, and it had 4 people in it. The report does not speculate as to how much fuel was on board, and doesn’t tell us estimated weights of the 4 passengers, but a new SR-20 G2 has a useful load of only 594 pounds with full fuel. My speculation would be one of an over-gross aircraft pulling off the ground, not climbing (“flying in ground effect”), and then doing an “Oh s–t! Here comes the trees” maneuver. Stall. Spin.
I don’t want to get into any speculation, but some facts that are known and bear mentioning:
1 - The airplane flew in from another airport, and would have used roughly 10 gallons of fuel for that trip. The same people who died in the later crash were on board when the airplane arrived at Greenwood.
2 - No fuel was purchased prior to departure from Greenwood.
I haven’t read or heard how much fuel was on board prior to the first flight that day, nor whether any additional baggage was added at Greenwood. Also unknown (to me, anyway) is whether the passengers sat in the same seats.
- Mike.
In reply to:
Why do you feel so strongly about ALWAYS doing a run up on every full stop and taxi back?
As a flight instructor, I like to always see a run-up and pre-take-off checklist performed.
I don’t like to think about a student, or any pilot, compiling a list, however short, of when they wouldn’t:
- drain the sumps
- use their checklist
- do a run-up
- skip a preflight
- etc. etc.
There are a lot of pilots who start out just cutting a corner here and there and then end up making all sorts of dangerous exceptions.
If once in a career an “unnecessary” run-up catches a potentially dangereous condition, all those “unnecessary” run-ups paid for themselves.
In reply to:
Also unknown (to me, anyway) is whether the passengers sat in the same seats
Mike,
ThatÂ’s a very insightful point. ItÂ’s not uncommon for me have my employees to kind of draw straws for the front seat then swap at different legs of the trip. I allow this if the weights allow for it.
One of the remarks in this accident report caught my attention as well: A witness said the take off roll was “long”. This reminds me of a flight I had with an instructor once, in the instructor’s own plane, a Cherokee 140. This fellow kept holding the nose down on the ground till he reached almost 80 knots before rotating…on a short runway at that. We almost burned up the entire runway before becoming airborne…at 80 knots, which slipped to 70 before it began to build again, with trees directly ahead. I could see the birdnests in the trees below as we barely cleared them. I asked why on earth he did that. He said, well, the cherokee was underpowered, so he wanted as much airspeed as possible before leaving the ground!! He was so confident of his procedure, I didn’t even bother to argue with him. I diplomatically suggested it doesn’t work that way, and let the matter drop.
Of course, if one wants maximum airspeed and maximum altitude as soon as possible (in terms of distance from starting point), you get the wheels of the ground as soon as possible, to rid yourself of the friction with the ground. It is absurd to try to build speed in excess of rotate speed, while in contact with ground. You will burn up far more runway, for a paltry increase in speed and…obviously…zero altitude gain. Rotate as soon as possible, build that speed quickly in ground effect, and you will gain the maximum altitude the quickest.
I know this is flying 101 for most of you, but lots and lots of pilots just don’t understand it…witness the instructor I flew with. If the SC accident were a stall spin while trying to avoid trees, as opposed to the “show off” take off theory, I wouldn’t be surprised if the pilot had the same misconception about rotate speeds and max altitude, as that instructor did.
Well here’s a short one. After spending a night at Walker’s Cay a few weeks ago, I found the ramp area was so full of stones and rocks of every size that anything much above idle power would be inviting damaging the prop. So after a good warm-up, I checked the mags at just over idle power to make sure they both worked then departed. The takeoff involved a slow application of power and a thorough scan of the guages. It’s a matter of balance: The risk of not finding an engine problem vs. the risk of damaging the prop. Flying the plane every day and knowing it’s general characteristics, I voted to save the prop on this occasion.
Interestingly there is a carcass of a new Piper just off the runway. Word is that it’s engine came off the mounts during takeoff. Lost a piece of the prop maybe?
Some planes are not too vulnerable to stone damage. But I won’t be returning my Lancair to Walker’s Cay unless surface conditions improve there.
Soon after receiving my license, I was visiting a friend at the local airport who had a 182. He had not been flying in a few weeks or so and said he was going to go for a short flight and asked if I wanted to go along. He rubbed his hand on the prop - that was the extent of his preflight. Needless to say, I stayed on the ground.
Brian Fowler SR20 #1393
In reply to:
Rotate as soon as possible…
Sounds like a soft field, where rolling resistance is a major factor.
I don’t have my Airplane Flying Handbook with me, but for paved short fields I teach to leave the aircraft on the ground until Vx (obstructions ahead) or Vy (no obstructions) and to rotate firmly at that speed and maintain it until clear. Raising the nose too soon increases induced drag, which on a paved surface will be more than the rolling resistance you’re trying to avoid.
I’ll try to quote a source when I get home, unless someone beats me to it.
BTW, Dave, what are your qualifications? I mean that as neutrally as possible - I don’t see a bio and it helps to know your level of experience when responding.
Eddie, My qualifications are that I was a philosophy major in college and am now a lawyer! Doesn’t that make me an authoritative aerodynamist? 
Sriously, I’m a pp, instrument, 1200 hrs, Pitts, Cherokees, Diamonds and Cessnas.
Now, to the issue at hand…and scientists, engineer types please weigh in with your opinions as well…rolling resistance (I would think depends in part on temperature, tire pressure and so on) vs induced drag…I don’t know the exact physics of the two compared, but would love to hear a more detailed explanation from you and others. To me, it seems almost intuitive, that drag in level ground effect, not while climbing, should be lower than that from rolling resistance. This is how I was taught, and what both my instructional manuals and airplane operating handbooks indicate. Otherwise, why wouldn’t one roll as long as possible on any and all runways?
The book on my Warrior backs this up…shortfield rotation is 50, stay ground effect until Vx is reached, then climb at Vx, which is 63. Otherwise rotate is at 55. Vy in the plane is 79. Under no circumstances with non-gusty winds does the book have a rotate speed that approaches either Vx or Vy and all the book performance measures, eg over 50 ft obstacles, etc are done at recommended rotate speeds. The only circumstance I can imagine when one would push the rotate speed much higher would be gusty winds, to guard against risk of stalling or settling back to the runway after rotation.
The 50 knot rotation for shortfield is with 25 degree flaps in the Warrior
OK, Dave, I’m back home now.
The first place I looked was the Private Pilot Practical Test Standards. That didn’t help much, simply referring to rotation at the “recommended speed” with acceleration to Vx or Vy as appropriate.
The Airplane Flying Handbook - FAA-H-8083-3 backs my technique. It includes the photo below, backing it up with “The airplane should be smoothly and firmly lifted off, or rotated, by applying back-elevator pressure as approaching Vx.”
So, it would appear your instructor’s technique that so unnerved you was likely according to “the book”.
Probably best to stick with the POH. The procedures there were developed by test pilots to get the most out of the aircraft. Homebrew techniques are rarely any better.
We may have to respectfully disagree on this. The instructors technique that unnerved me was rotating above Vy, which is 79 in the Cherokee. His method was nowhere near in accord with the actual book for a Cherokee 140, nor in accord with any of the three authorities you cite (which are not specific to a particular model). The book for the particular plane says rotate at 50 or 55 (depending on flaps), then accelerate to Vx (63) or Vy(79). The generic drawing you posted suggests rotating at Vx, which in my view would a bit faster than necessary, but would provide more positive control on rotation, with only a slight cost in altitude. The text references you cite state: “…rotate at recommended speed, with acceleration to Vx or Vy as appropriate” and “firmly lifted off, or rotated, by applying back-elevator pressure as approaching Vx”. Both clearly imply rotating before Vx, which is in accord with the book for that particular plane. In any event, neither the plane’s book, nor the authorities you cite, suggest building speed to Vy before rotating.
In reply to:
…neither the plane’s book, nor the authorities you cite, suggest building speed to Vy before rotating.
Normal short field technique assumes a 50’ obstacle. I explain to my students that most short fields are short for a reason - if there were no obstructions they just would have made the runway longer.
One reason they say to rotate just BEFORE the desired speed is that the plane is accelerating and if you wait too long you’ll accelerate THROUGH the desired airspeed before you can nail it. Not much of a factor in a C-150, BIG factor in an SR22.
I recommend doing exactly as the owner’s handbook says. Test pilots have allegedly tried different speeds/techniques and published the best one. I agree that holding the plane on PAST Vy will cost altitude at the obstruction or over a given time.
Still, absent model-specific technique, I’ll stand by the following:
Short field with obstruction - roll level to Vx, haul it off and keep Vx until the obstacle is safely cleared.
Short field without obstruction - roll level to Vy, haul it off and keep Vy until at a safe altitude.
If you’re ever in S FL we can do a few “hands on” trials and see what works best!