Consequence of disregarding density altitude (engines, military)
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Engine power....density altitude....airspeed.....pilot error.....all factors in this crash.
Bird Dogs were rather strong performers in their speed range with O-470 engines rated at 213 HP in an airframe (C170) that started out with only 150 HP and a full 4-seater down to a 2-seater. All the more so in a civilian use after having the military equipment removed for a lighter on the ramp weight.
I rule out density altitude as a causation because that factor was present for the entire flight leading up to the last turn.
What caught my attention was the prolonged apparent nap of the earth flying leading to a rising terrain ahead flight path which the plane could not outclimb and the speed was too fast to turn away from the obstacles ahead; that's pilot error.
IIRC, that bird dog was a locally based aircraft so hot/high conditions weren't a surprise to them, they were clearly flying for some time before the incident without much margin for ground clearance or altitude to respond to a downdraft over some of those ridges.
I'm not trying to be judgemental here, but it appears from the video that this pilot was needlessly maximizing the opportunities for such an outcome. The adverse consequences can be very unforgiving. There but for the grace ....
It looked like the pilot in the birddog crash would have turned left he could have had a better margin. When he was in that steep of a bank the chances of stalling are increased. Stall speed increases durning a bank.
Bird Dogs were rather strong performers in their speed range with O-470 engines rated at 213 HP in an airframe (C170) that started out with only 150 HP and a full 4-seater down to a 2-seater. All the more so in a civilian use after having the military equipment removed for a lighter on the ramp weight.
I rule out density altitude as a causation because that factor was present for the entire flight leading up to the last turn.
What caught my attention was the prolonged apparent nap of the earth flying leading to a rising terrain ahead flight path which the plane could not outclimb and the speed was too fast to turn away from the obstacles ahead; that's pilot error.
IIRC, that bird dog was a locally based aircraft so hot/high conditions weren't a surprise to them, they were clearly flying for some time before the incident without much margin for ground clearance or altitude to respond to a downdraft over some of those ridges.
I'm not trying to be judgemental here, but it appears from the video that this pilot was needlessly maximizing the opportunities for such an outcome. The adverse consequences can be very unforgiving. There but for the grace ....
I dunno.....watching that video I could almost feel the squishiness in the controls. He literally had nothing....no room for error at all. I don't know what the MSL was for where he was flying, or if the aircraft was at its service ceiling, but I did recognize that he barely made it over a much lower ridge in the minutes leading up to the crash. Surely he knew that the aircraft didn't have performance capability as he pointed the nose to that giant mountain? I could tell and I wasn't even behind the controls.
Density altitude for that engine and that propeller seems to be the elephant in the room to me. I'm amazed that he pushed that aircraft onward for so long when it was very apparent (to me) that it didn't have the bite it needed to climb.
I dunno.....watching that video I could almost feel the squishiness in the controls. He literally had nothing....no room for error at all. I don't know what the MSL was for where he was flying, or if the aircraft was at its service ceiling, but I did recognize that he barely made it over a much lower ridge in the minutes leading up to the crash. Surely he knew that the aircraft didn't have performance capability as he pointed the nose to that giant mountain? I could tell and I wasn't even behind the controls.
Density altitude for that engine and that propeller seems to be the elephant in the room to me. I'm amazed that he pushed that aircraft onward for so long when it was very apparent (to me) that it didn't have the bite it needed to climb.
The altitude in that area isn't that high for this area of the country; I've flown that area of rolling hills and it ranges from a valley floor of around 5,500' to the adjacent ridges at 7,500'. My guess is that the density altitude for most of that flight path was around 6,500'-7,000'. Well within the performance parameters of a L-19. I generally transit that area at 9,500' - 10,500' for reasonable terrain clearance, and higher to avoid turbulence which is common there during many months of the year.
The original military purpose of the bird dog was as a liason or observer aircraft of exceptional capability. Flying low and slow, nap of the earth, was it's forte in military applications. With a service ceiling of over 20,000' and over 1,000 fpm climb capability carrying 800 lbs loads, these aren't a poor substitute for a Cub at this altitude. They're one of the strongest performing two seat aircraft of their era.
Flying nap of the earth in a civilian situation was not necessary. These planes are desirable for their collectability and performance, trading for significantly more money than most legacy C182's with the later O-470 engines at 225/230 HP, and for several times the price points of the C170's from which they were derived. The 170's were noteworthy as a superb back country aircraft, designed to fly out of short, soft runways with nearby obstacles ... on only 150 HP with the fixed prop.
I mentioned seeing that video again to my flight instructor/FBO operator yesterday when I was getting fuel, and he kinda' groaned ... "oh, that's that video that they found of those guys who flew their bird dog into the hill". He's a tailwheel and aerobatic instructor with 25 years of ag spray work in his logbooks, too. He knows what it is to fly low and slow ... To him, it was readily apparent that they'd been flying nap of the earth for the fun of it and simply ignored putting themselves into a close encounter with rising terrain in all directions from which they could not outclimb. They literally flew the plane into the mountain side and their effort to avoid that resulted in the loss of control at low altitude with no room to recover. Density altitude was not the causation of the problem, this plane was not struggling along to clear the terrain along it's route of flight .... it was intentionally flown into those close, low clearance situations for which it was designed to fly.
AeroGuy, you might want to check with the folk who own & fly these bird dogs. They are prized for their abilities and there's no way that the engine/prop combination was struggling to "bite" the air ... well within it's capabilities.
More like a lesson on why you should have shoulder harnesses installed in your airplane.
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