Legality of deliberate incipient spin demo if AFM prohibits spinning
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My contention is that the DA40 is most probably spin resistant and very safe, with huge margins for error and mishandling
While on the subject of spinning. During my 'Wings" test at RAAF Point Cook 25 November 1952, the CFI Squadron Leader Vernon Sullivan (known as "Slam" Sullivan) was the instructor. We were flying Wirraway A20-214.
"Slam" told me to demonstrate a spin from 8000 ft. I did that and was about to recover from the 8 turn spin when he said something like "That's interesting - keep spinning, Trainee"
Eventually he said "you can recover now" so I did. The recovery was normal and I had not felt anything unusual during the spin. In any case, my attention had been on the rapidly approaching ground below us rather than watching the wings.
On the way back to Point Cook I asked him over the intercom what was "interesting". 'Slam' said he had noticed that during the spin one of the wings seemed to be flapping and that he had never seen this before. He seemed unconcerned and that was the last I heard of it.
About four years later a Point Cook based Wirraway crashed during a practice dive bombing exercise at a bombing range near Werribee, Victoria. The pilot was Flight Sergeant Ted Dillon who was a QFI at No 1 Advanced Flying Training School, Point Cook. Previously Ted had flown Meteors and Vampires fighters.
During the pull up from dropping a bomb on the bombing range, Ted rolled the aircraft into a steep climbing left hand turn. Suddenly one wing broke off and Ted was killed in the ensuing crash.
The Court of Inquiry found that the cause of the wing failing was likely a combination of metal fatigue exacerbated by the rolling "G' forces pulled by the pilot during the recovery from a steep dive. We had been briefed to always make a straight pull up after the dive and never to roll the aircraft while pulling up as the asymmetric lift forces involved could significantly lower the G force limit at which structural failure could occur.
In later years I wondered if by chance this was the same Wirraway I had been flying a few years earlier when my instructor, Squadron Leader Sullivan, saw one wing 'flapping' as he had described it.
"Slam" told me to demonstrate a spin from 8000 ft. I did that and was about to recover from the 8 turn spin when he said something like "That's interesting - keep spinning, Trainee"
Eventually he said "you can recover now" so I did. The recovery was normal and I had not felt anything unusual during the spin. In any case, my attention had been on the rapidly approaching ground below us rather than watching the wings.
On the way back to Point Cook I asked him over the intercom what was "interesting". 'Slam' said he had noticed that during the spin one of the wings seemed to be flapping and that he had never seen this before. He seemed unconcerned and that was the last I heard of it.
About four years later a Point Cook based Wirraway crashed during a practice dive bombing exercise at a bombing range near Werribee, Victoria. The pilot was Flight Sergeant Ted Dillon who was a QFI at No 1 Advanced Flying Training School, Point Cook. Previously Ted had flown Meteors and Vampires fighters.
During the pull up from dropping a bomb on the bombing range, Ted rolled the aircraft into a steep climbing left hand turn. Suddenly one wing broke off and Ted was killed in the ensuing crash.
The Court of Inquiry found that the cause of the wing failing was likely a combination of metal fatigue exacerbated by the rolling "G' forces pulled by the pilot during the recovery from a steep dive. We had been briefed to always make a straight pull up after the dive and never to roll the aircraft while pulling up as the asymmetric lift forces involved could significantly lower the G force limit at which structural failure could occur.
In later years I wondered if by chance this was the same Wirraway I had been flying a few years earlier when my instructor, Squadron Leader Sullivan, saw one wing 'flapping' as he had described it.
Last edited by Centaurus; 27th Nov 2019 at 08:28.
I'd contend there are safety margins in the aircraft. Doesn't mean i'll be spinning myself however...
I wonder how useful the spin training actually is in reality. As in, how many fresh CPL’s head out into the world and actually benefit from it through their career from the trusty 152 to an Airbus? If you’ve got fare paying pax on-board and you’re entering a spin, you’ve got some serious issues ! Most likely to stall on landing and perhaps when you’re pushing it to make it above some cloud when VFR and if it happens then, you’re in a world of pain most likely!
I wonder how useful the spin training actually is in reality. As in, how many fresh CPL’s head out into the world and actually benefit from it through their career from the trusty 152 to an Airbus? If you’ve got fare paying pax on-board and you’re entering a spin, you’ve got some serious issues ! Most likely to stall on landing and perhaps when you’re pushing it to make it above some cloud when VFR and if it happens then, you’re in a world of pain most likely!
1. it gives pilots a more attuned instinct to detecting when the aircraft is entering that part of the envelope and correctly avoiding it getting any further
and
2. it builds confidence in their ability to safely control an aircraft. Overconfidence is not a good trait in a pilot but neither is inappropriate timidity and fear.
I have on multiple occasions come across pilot's who hold some deep suspicions about aircraft and their ability to handle things if something untoward happened. An inadvertent stall/spin is the most common fear and to avoid that threat they sometimes fly the aircraft in ways that potentially reduce safety.
I have seen this more than once with people always landing very long or regularly need to go around or who dive the aircraft on their base/final turn destabilising their approach, all because they believe the aircraft is in danger of stalling when turning onto final and manouvering on approach when in fact they do not require that speed and well inside a safe envelope.
I am not qualified to comment on the benefits it would give to air transport pilots (not my game) but in the GA realm, I think stall/spins can account for a number of accidents where people are manouvering on approaches and departures in tricky circumstances (low cloud, engine difficulties, strong winds, steep turns in climb outs, showing off on low passes etc). Having an instinctive feel for when you are putting the aircraft close to a stall/spin seems to me to add some buffer against tragedy. Once you have entered a spin at typical heights these things occur at, you cannot recover in time, the point is to know what happens, to recognise when it is getting too close (without reducing your performance by 'over-diagnosing' it).
My 2c
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Great post Jonkster.
The Canadian's held on to the spin training requirement for longer than we did (and Europe/USA). They also put together this report: https://www.richstowell.com/document...a_TP13748E.pdf
“One feature that stands out in all except one of the 39 stall/spin accidents examined is that knowing how to recover from the stall or spin was of no benefit to the pilots in these circumstances. They stalled at altitudes so low that once the stall developed, a serious accident was in progress. Safety will be advanced therefore by preventing stalls and spins.”
The Canadian's held on to the spin training requirement for longer than we did (and Europe/USA). They also put together this report: https://www.richstowell.com/document...a_TP13748E.pdf
“One feature that stands out in all except one of the 39 stall/spin accidents examined is that knowing how to recover from the stall or spin was of no benefit to the pilots in these circumstances. They stalled at altitudes so low that once the stall developed, a serious accident was in progress. Safety will be advanced therefore by preventing stalls and spins.”
