Sting Sport down in Florida

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Warmi
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Sting Sport down in Florida

Post by Warmi »

Just happened this weekend.

https://aviation-safety.net/wikibase/wiki.php?id=218018

Looks like horizontal stabilizer fell off and the pilot had to rescue himself ( successfully ) with a chute.

Interestingly there is a bulletin board dated at 2012 specifically mentioning inspection of horizontal stabilizer connections:

Reports from the field indicate that trapped moisture may accumulate in the interior of the alignment fitting and possibly cause corrosion on any exposed metal surface. Aircraft that are located near coastal salt waters, whether stored inside or parked outside may be more susceptible to corrosion of any non-protected metal surfaces.

http://www.sting.aero/owners/notices/TL ... l%2012.pdf

Sounds like exactly what happened ...
Flying Sting S4 ( N184WA ) out of Illinois
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ShawnM
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Re: Sting Sport down in Florida

Post by ShawnM »

Thanks Warmi. This happened just east of me in Clermont on Saturday. This plane used to be owned by a friend of mine but he sold it when he moved from the Orlando area. If I remember correctly the horizontal stabilizer has to be REMOVED and inspected at each annual. I used to share a hangar with another Sting owner (that plane is now owned by another member on this forum) and I came in on day to fly my plane and the horizontal stabilizer was off his plane and the mechanic stated that it's part of the annual to inspect these bolts and pins. It's no easy task either given that it's sealed in with some pretty heavy duty silicone as well. He made sure he told me it was no picnic getting it off. :mrgreen:

I was also flying back from Southwest Florida around this same time Saturday and the winds were pretty turbulent down low. I dont know if this played a factor as well with the horizontal stabilizer but just sharing that it was a pretty bumpy ride below 4000 feet Saturday.

Keep in mind it could have departed the plane at the time of impact as well. I think I see it, or part of it, on the right side of the picture posted on the local news that covered the accident.

https://www.wesh.com/article/single-eng ... y/25208597
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Warmi
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Re: Sting Sport down in Florida

Post by Warmi »

I heard it from another source that it was stabilizer departing in flight but I don't know how he got that info - perhaps it was just a guess based on the picture alone or he had some insider info - not sure yet.

It kind of make sense to me given that the plane was located very close to the coast with salty water etc ...
Will see what the final verdict is ..

BTW ... Looking at my logs , I don't see any entries indicating compliance with this directive ... until mid 2017 the plane was maintained by SportAir USA ( the dealer ) - of all people they should know best what to do - perhaps they figured that since the plane was not located in coastal area , it was not necessary.
Flying Sting S4 ( N184WA ) out of Illinois
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ShawnM
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Re: Sting Sport down in Florida

Post by ShawnM »

Warmi wrote:I heard it from another source that it was stabilizer departing in flight but I don't know how he got that info - perhaps it was just a guess based on the picture alone or he had some insider info - not sure yet.

It kind of make sense to me given that the plane was located very close to the coast with salty water etc ...
Will see what the final verdict is ..
Interesting, we'll wait and see if the story develops as to why this may have happened.

Technically EVERYONE is close to a coast in Florida :mrgreen: Orlando is not really close to the coast or salty water at all. Not even salty air. I lived there for 22 years so I do know that. Given the high humidity we have in Florida it simply could have just been the moisture attacking the hardware if this is the cause. This is why we inspect these things.
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dstclair
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Re: Sting Sport down in Florida

Post by dstclair »

Warmi wrote:Interestingly there is a bulletin board dated at 2012 specifically mentioning inspection of horizontal stabilizer connections:

Reports from the field indicate that trapped moisture may accumulate in the interior of the alignment fitting and possibly cause corrosion on any exposed metal surface. Aircraft that are located near coastal salt waters, whether stored inside or parked outside may be more susceptible to corrosion of any non-protected metal surfaces.

http://www.sting.aero/owners/notices/TL ... l%2012.pdf
That was a a one-time Service Notice but there is a requirement to remove the wings and stabilizer every other annual (or 200 hrs, whichever comes first) and inspect/lubricate various components. I haven't found removing the silicon and sealing it back much of an issue -- YMMV.

It does look like the stabilizer is near the nose of the plane in the picture which indicates separation on impact or near the ground. I would expect the NTSB preliminary report to clarify this.
dave
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Warmi
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Re: Sting Sport down in Florida

Post by Warmi »

http://www.kathrynsreport.com/2018/11/t ... n494n.html

It reads to me like the pilot simply overstressed the plane - due to an ADSB alert he ended up in a 140 knots dive which was followed by a spin and recovery at which point his elevator gave away - they fund the elevator push-pull rod fractured with signs of overstress failure.

The VNE speed on the plane is 164 knots but the VA speed is 118.

What I find strange/disconcerting is his claim that after noticing 138 knots dive he abruptly reduced power to less than 50% which caused yaw and spin to the left... got to be more input than just reducing power to cause that ...sounds like an accelerated stall and spin perhaps ?
Flying Sting S4 ( N184WA ) out of Illinois
TimTaylor
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Re: Sting Sport down in Florida

Post by TimTaylor »

Sounds to me like an abrupt pull up from a high speed dive ripped the horizontal stabilizer and elevator off the airplane.
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MrMorden
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Re: Sting Sport down in Florida

Post by MrMorden »

Regardless of cause, this is a compelling example of the value of a ballistic parachute. In this case a non-survivable event was converted to a minor injury by appropriate use of the parachute system.
Andy Walker
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Sport Pilot ASEL, LSRI
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MrMorden
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Re: Sting Sport down in Florida

Post by MrMorden »

From Kathryn's Report:

"In a written statement, the pilot stated he was in cruise flight when he received an ADS-B traffic alert via a commercial application he had running on his smartphone. The traffic approached from his one o'clock position and closed at "a high rate of speed."

According to the pilot, he entered a shallow, descending turn to the left to increase separation with the traffic. As he levelled the airplane following the descent, he noted that his airspeed had increased to 138 knots. When he noted the airspeed, he "rapidly" reduced engine power below "50%" at which point the airplane yawed and entered a spin to the left. The pilot said he arrested the spin, and that the airplane initially responded to elevator inputs to raise the nose and level off. When the nose of the airplane pitched forward uncontrolled, the airplane entered a high-speed, nose-down descent, and the pilot deployed the BRS parachute."

I have so many questions. Chiefly:

1) If the traffic you are concerned with is approaching from 1 o'clock, why enter a *left* turn to avoid it, which completely blanks out your ability to see the traffic at all?

2) How does an airplane yaw into a spin at 138 knots? You can't spin unless you are stalled, and you are *not* stalling the airplane at that speed. There is no Universe in which reducing engine power at that speed creates a strong enough yaw to spin the airplane, *unless* as Tim mentioned he went into an abrupt over-G accelerated stall. But I can't imagine the kind of control deflection you'd need to get into an accelerated stall/spin at ~138 knots. Probably enough to tear the tail off...

Such a weird set of circumstances and odd decisions.

Also:

"The stabilizer mount plate and mounting studs themselves were intact and undamaged, but the composite structure and adhesive joints surrounding them were torn and peeled away from the main tail structure. The elevator push-pull tube was fractured at the point where the tube exited the empennage and the fracture surfaces displayed signatures consistent with overstress failure."

Definitely supports Tim's hypothesis.
Andy Walker
Athens, GA
Sport Pilot ASEL, LSRI
2007 Flight Design CTSW E-LSA
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Warmi
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Re: Sting Sport down in Florida

Post by Warmi »

Yeah , I think Tim is right - it sounds like a case of really bad recovery from a pretty benign dive ( at 138 knots he still had almost 30 knots safety margin buffer to VNE)

As Mr Morden pointed out what it also highlights is the fact that a BRS chute is not just a psychological crutch but truly life saving piece of equipment.

PS.

A Sting sport plane has an almost 360 degree open bubble canopy so a shallow left descending turn is not as bad choice as it sound for this particular scenario.
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Re: Sting Sport down in Florida

Post by TimTaylor »

There is no question, a parachute can be of great value and save your life. On the other hand, if you are a good pilot and pay attention to what's going on, how many times in your flying career would you ever need it? I guess it's like fire insurance on your house. We all have it, but most never use it, thank goodness. IMHO, it would be a good thing to have, but I'm not going to worry about the fact I don't have one.

If I had a parachute, I would have to buy an airplane to put it in. Years ago, I had a parachute and made quite a few 60 second delays from 12,000 feet. What we won't do when in our college days?
Retired from flying.
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