The Cessna 170B pilot departed a remote, off-airport site near Glennallen, Alaska, to search for a moose he had shot earlier in the day. A witness observed the airplane perform a series of low-altitude maneuvers before flying by his location about 80 to 100 feet above the ground.
The airplane then began a left turn, and the nose pitched down abruptly and began to spin. The airplane subsequently descended vertically, nose first, and it collided with the tundra and brush-covered terrain. The pilot was killed.
Given the lack of mechanical deficiencies with the airplane and engine, the witness statements, and the nature of the damage to the airplane, it is likely that the pilot inadvertently stalled and spun the airplane at a low altitude and was unable to recover.
The NTSB determined the probable cause as the pilot’s failure to maintain adequate airspeed while maneuvering at a low altitude, which resulted in an aerodynamic stall/spin and impact with the ground.
NTSB Identification: ANC13FA093
This August 2013 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.
Always a sad ending for him and his family.
Ultimately caused by a defective control yoke actuator.
It has been proven time and time again that no matter how many devices and equip. is aboard an aircraft, what’s going to kill you is that little piece of mush between your ears and the attitude that goes with that is the killing factor. As long as pilots continue to fly with their heads up there yingyang and pretend they know more than the equipment is telling them, there will continue to be fatalities.
You may have seen an air traffic accident programme on TV where a captain, when he got a stall warning, …stick shaker, siren, buffeting etc. due to ice on the wings when on a final approach, he actually pulled the stick back!!!….. thus killing everyone on board. I’m only a PPL and there is no way anyone at the flying school I went to would do that, ever, even from say ten or so hours in….we were taught certain fundamentals which you had to ALWAYS be aware of regardless of what was going on around you, they were paramount and it was stressed that way. The tragedy we’re talking about here, in my opinion and with assumptions made, would never happen to any members of our school, I’m certain……we were taught airspeed is the most important thing to monitor when manoeuvering at slow speed and especially at low level where there is no chance, zero, of recovering a spin…certain death is the way it was put to me and aimed particularly at the climbing turn after take off and the descending one from base leg to final approach when perhaps concentrating on lining up with the runway. It was rammed home so hard that we all learned to apply that caution at ALL times in the situation described, i.e. slow and low and also it’s there at all times. It’s ingrained into me so much that I may make some mistakes and have done so in my time but not ever letting airspeed go dangerously low.
From what I’ve read re. the NTSB report the plane began a left turn & I’m assuming it was a near enough level turn since a descending one would be unlikely at the height he was at and a climbing one wasn’t mentioned either. If the pilot was flying slow anyway he may have been at such a speed where just the level turn would be enough for the plane to spin simply because the left wing would then slow to a speed lower than that of the right wing and would drop immediately. So perhaps he was at that critical speed which kept the plane flying straight and level and where just the slightest loss of speed of a wing would cause a spin? A level turn would do this.There are a few assumptions made here and we’ll never know the full facts but the above seems a possibility to me. I believe the turn itself caused the spin and that had he not made that turn then he’d have stayed airborne at the airspeed he was at, ..just.
Bernoulli theorem was based on pressure differential,,, the speed of the aerofoil is primary,,,,so folks,,whatever you fly,,,,ASI is primary,,,ADI is next,,,always keep speed in hand ,,,,for any manuever,,,
I believe it’s time the NTSB and everyone else would refer to stalls/spins by angle of attack instead of airspeed. This is a more accurate and proper term to use. It would be more proper and accurate to say the pilot failed to maintain a safe angle of attack.
While it is correct that it is angle of attack that is critical to the wing many aircraft, likely including this C-170, do not have an AOA gauge. Airspeed indicators are required equipment that all aircraft have. Airspeed management will keep you from stalling in most cases, there are of course exceptions. Keep in mind the G load that the aircraft is carrying and adjust stall speed to that load. The higher the bank the more power or reduce the AOA by dropping the nose. Aerobatic pilots do not routinely use AOA gauges, but rather they use airpeed indication along with sound, attitude and throttle position to know what the airplane is doing and they do not often stall inadvertently.
“An aircraft can be stalled at any airspeed and any attitude”. AOA is a good thing to know, but it’s not in the center of my view in any SE GA aircraft I have flown… except my own in which I installed an AOA gage five or six years ago. Airspeed and an acute awareness of attitude … and the affect of load factors on stall speed… are pretty darn important. I agree with your comments about ASI vis AOA awareness Greg. We fly the planes as equipped, not as we wish they were equipped.
According to the NTSB Factual report the pilot was looking for a moose he’d shot and that he believed it died in a very brushy area. He was highly motivated to find it! A witness reported he over flew the area, making various turns “at approximately 80 to 100 feet above the ground, traveling at an estimated 45 mph.” Not mentioned in the accident report is whether or not the C170 had lift enhancing devices on the wings. Regardless, this is right on the cusp of a stall. Any!! ANY! yaw at this airspeed would potentially contribute to a spin. Regardless, recovery from even a stall would consume more than the altitude available. The pilot’s mission focus, obvious distraction, plus his lack of experience (186 hours total logged time, 12 hours in previous 180 days) suggests that no matter how his cockpit was equipped (ASI only, AOA only, or ASI + AOA) the outcome was preordained.
I was always taught to keep my eye on airspeed during all manoeuvres particularly when at low speed and when turning. This I do always and it comes naturally, something I couldn’t forget to do.