TBM Flat Spins 5 Die

Would ailerons have been better? I would think you'd use rudder to keep straight and level at stall. No?

 

In a full stall or a spin, ailerons are not effective. Full forward stick, opposite rudder to the direction of the spin, and then a steady smooth pullout after the spin is stopped. A buddy of ours started his air show routine with a 13 turn inverted spin and thought nothing of it.

 

I have been wanting to ask these questions since this thread first started:

1) - Was it really a FLAT spin? How do they know? (from crash evidence, perhaps?)

2) - If it was really in a flat spin - is this plane actually recoverable from such a situation? Some 1950s fighters had to have anti-spin rockets to get out of a truly flat spin...I suspect that all of this "spin recovery" stuff in 152 Cessnas may not even remotely apply here.

 

I certainly can't say what kind of spin the TBM was in but I can say that most modern airplanes must have pro spin inputs in order to get to that point. I have done spins in several airplanes, my first T-34 would spin but the recovery was so easy that you would literally point the stick at the line you wanted it to stop and it would stop immediately. My current T-34 won't spin. With full stick and full rudder it goes over the top and then just does a series of vertical snap rolls, which isn't really a spin.

The Extra 300 is also very easy to spin but to go into a flat spin you have to add power and opposite full aileron to bring the nose up and level the wings. I always did it in the proper order so not 100% sure whether you could enter a flat spin in a different way. But imagine what it takes to get into a flat spin. Full aft stick, full rudder power off, then when you are into the spin power up and add opposite aileron.

I used to do inverted flat spins in the Extra but I haven't in quite some time.

A very important training item that is not taught very often. I learned when at Stallion 51. The stall speed of the P-51 is 98mph but when you pull it up into a wing over, our speed was down to 60mph. The stick was moved from corner to corner and the airplane didn't move at all. The rudder worked fairly well but no stall. Zero G's = no lift. No lift means no stall.

I think we stalled the Mustang a thousand times, accelerated, uncoordinated, straight up, straight down, clean and dirty. Lot's of fun but it did get old. I highly recommend upset training it will save your life.

I am not a aeronautical engineer or an instructor so I may have missed some of the finer points, but this is what I remember.

 

They don't know if was a FLAT spin, or even a spin at all. What they know is, apparently the pilot said something about a "spin" on the radio, and various witnesses on the ground said they saw it appear to be spinning out of the clouds.

As for recovery, I imagine a TBM would be reasonably recoverable, but I'd never like to find out. The airplanes which have problems with spins are twins, with a lot of mass out on the wings and wide center of gravity envelopes.

I would certainly think that, given enough altitude, you could recover from a flat spin in a TBM, with power if nothing else. However, that would require enough altitude, and the presence of mind to recognize the situation (not sure I'd have enough presence of mind, and I've done lots of spins).

If it was a spin, it most likely got into it because of icing. Ice will both increase the weight and increase the stall speed, and if ice forms asymmetrically on the wings, you could have a situation where one wing stalls before the other (potentially well above the "official" stall speed), and down you go, into a spin. Not necessarily a flat one, however.

 

Don- A spin in IFR conditions requires that the pilot be able to recognize from the instruments what is happening. For someone who had never had a spin demonstrated with head down to see what the instruments were doing, could be difficult to initially recognize. Possibly add some icing to the equation, especially this time of year, and the problem is compounded. Sounds like he did eventually recognize he was in a spin. Most spins done for training are in VFR conditions, where direction of spin and type of spin can be determined against visual references, and appropriate corrective actions taken. For most GGA aircraft, simply unloading will get you out of it and rudder use will speed the recovery if you know which way to push it.

This poor guy was in Colorado, and may not have known the exact terrain elevation where he was. With 50+ mountains over 14,000' in Colorado, dumping the nose may not have appealed to him too much.

 

This is something that I think should be taught to everyone (along with actually doing spins, rather than only teaching spin prevention- that should be mandatory- spins are fun and experiencing one along with a recovery might save your life). Anyway, like you said its important to understand that exceeding the critical AoA is what stalls a wing, not low airspeed.

In fact, in the first block of primary training, the AF has you do a "stability demonstration" to demonstrate this very fact that if you don't ask anything of the wing (i.e. keep the AoA low and don't demand lift) the plane won't stall, and if it doesn't stall it can't spin. If I recall, procedure for that demo was something like set power to midrange, pitch to 45 deg nose high, allow speed to bleed off to stick shaker which at 1 g is around 80 kts, then move PCL to idle and neutralize the controls (which was the departure from controlled flight boldface for that aircraft). I think the plane slowed down to like 45 kts. Warning: the oil systems in most planes might not like the near-zero g this causes.

 

Tim- Affirmative, airplanes go ballistic fairly easily as long as you do nothing to upset the balance. Have seen less than 100 KTAS in an F-15 (in the back seat) in a vertical fight. Not too smart tactically because someone will blow through and kill you, but fun during ACT. I asked the pilot if the other F-15 was wagging his wings for a knock-it-off and he said no, his airplane just stopped flying and he was overcontrolling her. Recovery for that was to rudder over like a hammerhead. Killed him on the way up and on the way down.

 

On the topic of AOA and wing stalls I'll mention that the opposite is true as well- you know that, but maybe someone else reading is new to aviation and this might help them- you can stall at much higher than a published "stall speed" if you increase g loading (AOA). I recall stalling in a set of extended trail at probably more than 3 times what the plane's stall speed was. The same thing can happen in traffic pattern turns, and is the cause of many crashes. This (an accelerated stall) could've been what got the TBM pilot.
Come to think of it I don't think I did traffic pattern stalls (i.e. getting slow on overshooting and undershooting final turns) when getting my PPL a few years back- just straight ahead power on and power off stalls. Is this something anyone did as part of their private pilot rating?

 

I can only refer to what my training was in the dark ages. I had stalls in every conceivable situation, power on and power off. Stalls straight ahead, "gliding", slow speed turns, climbing turns, power on tight turns, etc. Heavy training on stalls and spins . Three airplanes stick in my memory as nasty stallers; PT-19, PT-22, and the BT-13.

 

Tim- Affirmative, in WW-II they called them accelerated or high speed stalls like the one that killed Tommy McGuire. We referred to them as departing controlled flight when you exceeded AoA limits. Recovery was generally stick forward until the AoA dropped to where she was controllable. Some recent aircraft have nasty departure characteristics. The F-111 would tend to have the nose slice off right or left because the rudder was blanked at high AoA and the ventral strakes were not big enough. The only time they intentionally spun an F-111, during early testing, they lost the aircraft. Even though fitted with a spin chute, it ripped off as soon as deployed, and she was still spinning on impact. Crew ejected successfully. Never tried that again.

 

The feds released a statement today saying that the pilot radioed that he was

"in a flat spin and was trying to recover",

just before they crashed.

 

When I was in learning , the term was as Taz said, high speed stall and I was trained to experience them. I was never introduced to flat spins but knowing a bit about the phenomenon I think that if I knew that I was in one , I would go stick forward , rudder in the opposite direction of the spin, aileron in the opposite direction of the spin, and a healthy blast of power. Okay experts, I'm open to criticism. By the way, I got out of a deep spin in a PT-19 with power but I don't know if it would work here but I think that it would.

 

The actual NTSB report:

CEN14FA167

 

Bob- For us it was forward and centered on the stick, and the rudder was useless because it was blanked. The procedure you learned would work for most GA aircraft or high performance twin rudder aircraft.

That quote of seeing the aircraft flying around the reservoir for several minutes puts a different light on things if correct.

 

I am very skeptical about the things that eyewitnesses report-- especially their sense of time. Notice that the NTSB did NOT quote any of these eyewitnesses.

 

A blast of power can often force the nose down with forward stick and opposite rudder. There is a chance that there is enough airflow over the advancing wing to force it down with left aileron. You don't just sit there and let it happen.

 

…esp since another 'eyewitness' said "… and it suddenly dropped out of the clouds and crashed into the water…."

I'll bet every viewer has a different 'recollection'….mostly unreliable!

 

James- Affirmative on that.

 

From the look of the wreckage it appears that the left wing had impacted in a flat position and bent upward. That would imply a flat spin to me.

 

From some of the accidents in the air shows I'll bet that they never knew it. Possibly 18 to 20 G impact straight up the spine. We saw one guy survive an 18 G flat impact and busted through the bottom of an aluminum seat but survived serious injury because he was wearing a seat pack chute that must have ameliorated the load.

 

The owner only bought the plane 18 days before the accident.