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Wouldn’t a well trained pilot (like somebody learning on the SR71) be very familiar with what a slow airplane feels like? I’m shocked that a skilled pilot would

Wouldn’t a well trained pilot (like somebody learning on the SR71) be very familiar with what a slow airplane feels like? I’m shocked that a skilled pilot would have allowed that plane to get so dangerously slow.

GekkePrutser 5y ago
Yeah it sounds like a tall tale. "Falling at a slight bank" sounds like ideal conditions for onset of a spin. Which a pilot would be very wary of when close to the ground because it means certain death. Also, would it be possible to fly level at such a speed in an SR71? And isn't there a HUD and vertical speed warner? On the other hand their expectation of being grounded sounds pretty accurate :) Oh well I never flew anything better than a Cessna 172 so don't take my word for it.
- imoverclocked 5y ago
  > isn't there a HUD and vertical speed warner? On a 1960's SR-71? Probably not [1]. [1] https://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird#/media/File:Lockheed_SR-71A_Blackbird,_National_Museum_of_the_United_States_Air_Force,_Wright-Patterson_Air_Force_Base,_near_Dayton,_Ohio,_USA,_cockpit,_forward_view.png https://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird#/medi...
- jshier 5y ago
  The human mind, even one highly trained, is capable of ignoring all sorts of inputs when conditions don't match expectations. For an SR-71 pilot I can easily imagine flying low and slow could create such an issue. It's scary in general just how many airline crashes are "controlled flight into terrain". In 2009, Air France flight 447 crashed off the coast of Brazil after the pilots flew it at a stall from 35,000 feet. https://admiralcloudberg.medium.com/?p=8a7678c37982 https://admiralcloudberg.medium.com/?p=8a7678c37982
  - loonster 5y ago
    Thanks, this was a good read. I decided to search HN, and this [0] is the most popular thread on "Air France 447". [0] https://news.ycombinator.com/item?id=3327202 https://news.ycombinator.com/item?id=3327202
imoverclocked 5y ago
We are all human and this was probably an unusual exercise. Given their distraction of trying to find a field in this aircraft, I can easily imagine how quickly the plane got away from them. 152 kts is roughly 174 mph... imagine trying to find an address when going any slower than 200 mph is potentially fatal.
teeray 5y ago
Yeah, probably. But in aeronautical decision making training, you learn that other stuff going on in the cockpit can cause “simple” things to get overlooked. They were looking for the field in low visibility which took the pilot’s attention off the aeronautical health of the aircraft. This is why the stall horn and things like GPWS callouts are a thing. His skill did come into play when he had an atavistic sense that something was wrong, confirmed it was so, and firewalled the throttles.
Diesel555 5y ago
Some aircraft don't buffet much when they get slow, while other aircraft may buffet a lot (slow as a simple term for high angle of attack (AOA), but high AOA can occur from G-forces - back stick pressure - as well). Those aircraft also use a digital flight control system that commands G instead of direct deflection of the surfaces. Therefore the aircraft feels the same at the speeds in which it is capable of delivering the G it is asked to deliver. The same back stick pressure delivers the same G. This is much different than a mechanical system in which you get more G if you are faster. The F-16 is one such aircraft. It feels very similar at 250 knots and 650 knots. Of course an experienced pilot immediately recognizes when the aircraft hits the G-limit due to speed. For example, at 200 knots it can't pull 5 Gs. But that only occurs when you are pulling on the stick and not in straight and level flight. The angle of attack of being slow (just being more leaned back in the jet) is more subtle and and doesn't usually present itself until you are already really slow. The automatic flaperons and leading edge flaps, which give the wing more camber automatically, are partially a reason for this. Point is, the slowness maybe not be as obvious as you think.
throwaway0a5e 5y ago
You don't get a lot of practice at the limit of the flight envelope in an SR71 for the same reasons crane operators don't do a ton of heavy picks in high winds. It's not worth the risk to the equipment.
- lostlogin 5y ago
  > It's not worth the risk to the equipment. … or life.

GekkePrutser 5y ago

Yeah it sounds like a tall tale. "Falling at a slight bank" sounds like ideal conditions for onset of a spin. Which a pilot would be very wary of when close to the ground because it means certain death. Also, would it be possible to fly level at such a speed in an SR71? And isn't there a HUD and vertical speed warner? On the other hand their expectation of being grounded sounds pretty accurate :) Oh well I never flew anything better than a Cessna 172 so don't take my word for it.

imoverclocked 5y ago
> isn't there a HUD and vertical speed warner? On a 1960's SR-71? Probably not [1]. [1] https://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird#/media/File:Lockheed_SR-71A_Blackbird,_National_Museum_of_the_United_States_Air_Force,_Wright-Patterson_Air_Force_Base,_near_Dayton,_Ohio,_USA,_cockpit,_forward_view.png https://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird#/medi...
jshier 5y ago
The human mind, even one highly trained, is capable of ignoring all sorts of inputs when conditions don't match expectations. For an SR-71 pilot I can easily imagine flying low and slow could create such an issue. It's scary in general just how many airline crashes are "controlled flight into terrain". In 2009, Air France flight 447 crashed off the coast of Brazil after the pilots flew it at a stall from 35,000 feet. https://admiralcloudberg.medium.com/?p=8a7678c37982 https://admiralcloudberg.medium.com/?p=8a7678c37982
- loonster 5y ago
  Thanks, this was a good read. I decided to search HN, and this [0] is the most popular thread on "Air France 447". [0] https://news.ycombinator.com/item?id=3327202 https://news.ycombinator.com/item?id=3327202

imoverclocked 5y ago

We are all human and this was probably an unusual exercise. Given their distraction of trying to find a field in this aircraft, I can easily imagine how quickly the plane got away from them. 152 kts is roughly 174 mph... imagine trying to find an address when going any slower than 200 mph is potentially fatal.

teeray 5y ago

Yeah, probably. But in aeronautical decision making training, you learn that other stuff going on in the cockpit can cause “simple” things to get overlooked. They were looking for the field in low visibility which took the pilot’s attention off the aeronautical health of the aircraft. This is why the stall horn and things like GPWS callouts are a thing. His skill did come into play when he had an atavistic sense that something was wrong, confirmed it was so, and firewalled the throttles.

Diesel555 5y ago

Some aircraft don't buffet much when they get slow, while other aircraft may buffet a lot (slow as a simple term for high angle of attack (AOA), but high AOA can occur from G-forces - back stick pressure - as well). Those aircraft also use a digital flight control system that commands G instead of direct deflection of the surfaces. Therefore the aircraft feels the same at the speeds in which it is capable of delivering the G it is asked to deliver. The same back stick pressure delivers the same G. This is much different than a mechanical system in which you get more G if you are faster. The F-16 is one such aircraft. It feels very similar at 250 knots and 650 knots. Of course an experienced pilot immediately recognizes when the aircraft hits the G-limit due to speed. For example, at 200 knots it can't pull 5 Gs. But that only occurs when you are pulling on the stick and not in straight and level flight. The angle of attack of being slow (just being more leaned back in the jet) is more subtle and and doesn't usually present itself until you are already really slow. The automatic flaperons and leading edge flaps, which give the wing more camber automatically, are partially a reason for this. Point is, the slowness maybe not be as obvious as you think.

throwaway0a5e 5y ago

You don't get a lot of practice at the limit of the flight envelope in an SR71 for the same reasons crane operators don't do a ton of heavy picks in high winds. It's not worth the risk to the equipment.

lostlogin 5y ago
> It's not worth the risk to the equipment. … or life.