The student pilot, who had 15 hours of flight experience, was performing an instructional flight with her flight instructor and a passenger. According to GPS data, the Cessna 172 landed and then took off from a grass airstrip in New Milford, Connecticut, climbed about 150′, then hit terrain about 1,000′ past the end of the runway.
There were no known eyewitnesses, and the student pilot and passenger did not recall the accident due to their injuries. The flight instructor died in the crash.
An examination of the wreckage did not reveal any evidence of a preaccident mechanical malfunction or anomaly.
An examination of the flight controls revealed that the wing flaps were in the fully extended (40º) position at impact. The airplane’s operating checklist stated that normal and obstacle clearance takeoffs are performed with wing flaps up, and flap settings greater than 10º are not recommended at any time for takeoff.
Upon landing on the grass runway, the flaps should have been retracted as part of the after-landing checklist, then confirmed up as part of the before takeoff and takeoff checklists.
It is likely that the flap setting at the time of takeoff resulted in an aerodynamic stall and loss of control during the initial climb.
It could not be determined who was at the controls at the time of the takeoff and loss of airplane control. However, the flight instructor, as pilot in command, was responsible for the operation and safety of the flight and should have ensured that the flaps were retracted before takeoff. He also should have anticipated and corrected any significant errors made by the student.
Probable cause: The flight instructor’s failure to ensure that the wing flaps were properly configured for takeoff, which resulted in an aerodynamic stall and loss of control during the initial climb.
NTSB Identification: ERA17FA272
This August 2017 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
Our flight school recently added a C172M, with 150hp and 40 degree flap system. I remembered this article and comments so halfway through one of our climbouts this morning, I lowered the flaps to 40. The pitch had to be adjusted downward substantially to keep about Vx speed. The density altitude was about 700ft, two people, fuel between three-quarters and full. The VSI finally settled solidly at 400fpm. Tests can be done at higher altitudes in the practice area to estimate performance at higher airports. When I flew at Leadville, CO, they mentioned flaps are never set more than 10 degrees for approaches because they new that there (nearly 10,000 elevation), the airplane would not climb with more than 10 degrees of flaps. It’s critical to manage the pitch to maintain an efficient airspeed, and get used to a flatter climb. Trying to force the airplane to fly the normal climb angle or allowing the speed to go well below Vx will surely either lead to a stall or prevent a climb.
There’s a book floating around called GA by the Numbers or similar. In a 100 hp C150, 90 mph (it is an old book) plus full flaps will give you 600 FPM – DOWN! If you want to climb in a 150 with full flaps, expect to nail the airspeed at 55 so the houses get smaller (at about +150 FPM) instead of larger. Good idea to practice this at altitude once in a while, nice to know if you want to get down in a hurry someday (in one piece).
I don’t see why a pilot would use 40deg flaps, except in an emergency descent.? The rate of descent is very high and it takes a strong pull to flare. My C175 with 180 hp will not climb with 40 degs of flaps., and that’s when 300 lb less than gross weight, me and full fuel. !
My POH states that short field take offs are done with 20 degrees of flaps, and gets off the runway within 500 ft, again at ~ 2,000 lb.
Use the POH to get the specified performance. Do anything else and you’re a test pilot.
I use F40 in my 185 everyday when landing at my 1400’ strip. Using full flaps is very common when landing on short, backcountry strips. The extra drag helps with airspeed and profile control and meets Owner’s Manual/POH recommendations for short field landings.
Regardless of which flap setting you use for landing, the flap setting for takeoff needs to be checked and verified prior to every takeoff.
You would be surprised at the full flap go around performance (at sea level, anyway) with your airplane. That is something I do with students during training, 150’s, 175’s, 182’s or otherwise. Flap motors do fail…
Jim, I know what you mean. When first flying a Skyhawk just before my PVT checkride, we used 20 degrees of flaps and it seemed to feel perfect. Years later when I was working as a cfi in a different part of the country, one of the flight school managers asked me what’s this with the 20 degrees of flaps. He was in favor of the general concept that it is best to land an airplane at the slowest speed in order to minimize the landing rollout and to minimize chances of loss of control brought on by excessive landing speed. It’s really a basic concept out of the FAA manual.
Full flaps doesn’t necessarily change the descent angle – if you use power to maintain desired speed, you can descend at any angle with the elevator (within limits of course of the drag being produced). I get established with pitch and power, and trim for hands off. When power is reduced I rough trim a little more so the back pressure isn’t excessive throughout the round-out to the touchdown. A little power can be used nearing touchdown to help relieve the back pressure needed and soften the touchdown. I agree the landing is more of a challenge with the 40 degree system – the elevator has less authority.
Warren, I second you. A flap setting of 20° is a good standard setting. However, I recommend zero flaps at windspeed above 20 kts, 10° at windspeed 10 to 20 kts and full flaps at short fields or at tailwind.
Once again, my mantra prior to takeoff in any airplane is a final check of flaps, fuel, trim. FFT works in any airplane I have flown, and actually saved my bacon once in a friend’s corporate jet after a landing and taxi back for takeoff.
Flaps. Set for takeoff.
Fuel. Selector(s) set, mixture set for density altitude, boost/fuel pump(s) as required.
Trim. Set for takeoff.
Excellent procedure, but mistakes happen and what then. Based on my experience in training I wonder if the departure could have been made even with full flaps. Before I solo a student, we do a couple of the go-arounds leaving the flaps full down to simulate a flap system failure and realistic critical circumstance for the student. Most of these were done at another CT airport (and I have flown at the New Milford airport). What we learn is under the given conditions, there is no reason to be alarmed as we still would see the airplane easily climb back to pattern altitude at about 500 fpm. Controls are used in a normal way – that is, full power, pitch to airspeed (about 65 kts, minimum drag speed). It’s simply preparation for an abnormal condition that could reasonably happen. This Cessna also had a 160 hp engine (according to the full narrative) but a 40 degree flap system and a passenger. I believe it still may have been capable of climbing out based on my experience with 30 degree flap models giving much room for error. It did climb to 150 ft agl (higher than where we started some go-arounds) and crashed several hundred feet before reaching the tree line. Climbouts with reduced climb performance (high density altitude or inadvertent extra drag) can be intimidating. It is not easy (psychologically) to keep the pitch lower to maintain the correct airspeed and be patient while flying a flatter departure. But it is an abnormal condition worth practicing in a safe manner at an appropriate location or in the practice area.
The time to experience a full flap go around is with an instructor during a training session. A low experience pilot doing it for real the first time can be an uncomfortable and even challenging situation. What you do is a good thing.