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Aborted takeoff in Glider

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Aborted takeoff in Glider

Old 9th Oct 2017, 08:12
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Aborted takeoff in Glider

Aborted outside the perimeter boundary, into trees.

Edit:
In deference to the hospitalised pilot, I've deleted the link to the apparently unauthorised video.

Perhaps he will authorise its use in the future.

I wish him a speedy recovery.


Mjb

Last edited by mickjoebill; 11th Oct 2017 at 13:02.
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Old 9th Oct 2017, 13:04
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airbrake not guarded

I have over 2,500 hours in gliders and the cause of this accident is obvious. The airbrakes were not locked and they opened during the takeoff roll. The pilot's left hand was guarding the tow release and not the airbrake handle so the pilot was completely unaware that the airbrakes had opened.

The hand should never be on the tow release during takeoff. Near is ok but, in my opinion, far better to guard the airbrakes.

What happened to "brakes closed and locked - ready for hook up"?

Why did he release? It was still flying and under control.


Andy

Last edited by EXDAC; 9th Oct 2017 at 13:16. Reason: typo fix
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Old 9th Oct 2017, 13:52
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Originally Posted by EXDAC View Post
Why did he release? It was still flying and under control.


Andy
It looks like he was given the line by the tug, as he only released after the tension pinged off.
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Old 9th Oct 2017, 16:02
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looked like he pulled the release by error TBH.......... silly to keep your hand firmly on it ...........
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Old 9th Oct 2017, 16:40
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He hadn't locked his airbrakes and they were sucked open once speed built up so consequently his climb rate was very slow. He was quite correct in guarding the release.
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Old 9th Oct 2017, 16:44
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Apparently this accident
Pilot in glider crash narrowly escapes falling into quarry - Leicester Mercury

Take a copy if you want as in like 'now' as from the comments it appears the pilot concerned wants it taken down from FB....though how it got there in the first place is a question indeed.

The BGA/instructors now teach that the hand must be on the release at least until the end of the ground run for all launches.
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Old 9th Oct 2017, 19:08
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He hadn't locked his airbrakes and they were sucked open once speed built up so
Does this suck-up occur in other makes?
Not possible/desirable to have it spring loaded? Do gliders only use speed brakes at landing phase so pulling against a spring or aerodynamic tab is not a physical ordeal?

Mjb
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Old 9th Oct 2017, 20:06
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If you're talking about the blue handle just above the pilots left hand, it jumps rearward at about the 30 second mark...not checked and locked, or a malfunction in the latch mechanism?
At about 1.10, he says FFS...that's when he should have picked it up, if not earlier when he noticed the glider wasn't performing like it should be.

Either way....ouch!!

Last edited by bgbazz; 9th Oct 2017 at 20:29.
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Old 9th Oct 2017, 20:16
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"The BGA/instructors now teach that the hand must be on the release at least until the end of the ground run for all launches."

That may be appropriate for a winch launch but not for aerotow in the gliders I have the most time in. ASW-19b over 1500 hours and ASW-28 over 850 hours - I always started aerotow takeoff roll with airbrakes open and closed them when I have good roll control. Not possible to have the left hand on the release and the airbrake handle. Also not possible for flapped gliders which start with negative flap and then change flap setting when speed increases.

Andy

Last edited by EXDAC; 9th Oct 2017 at 21:12.
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Old 9th Oct 2017, 20:28
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over-center lock

"Not possible/desirable to have it spring loaded?"

On most, if not all, gliders the airbrakes have an over-center locking mechanism. The handle moves forward until the brake caps are flush with the wing then additional forward movement of the handle activates the over-center locking mechanism. It is usually not possible for an external observer to see if the brakes are locked only that they are closed.

When unlocked airbrakes suck open depends on the glider type. On the ASW-19b they stay closed until lift off then bang full open. I painted a red bar on my ASW-19b airbrake control rod. The red paint was completely hidden when the brakes were locked.

A properly executed control check requires the airbrakes to be opened fully then closed and locked.

Andy

Last edited by EXDAC; 9th Oct 2017 at 20:38. Reason: fix typo
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Old 9th Oct 2017, 21:50
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The Piggott Hook:

https://www.dg-flugzeugbau.de/en/library/piggott-hook
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Old 9th Oct 2017, 23:05
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Most airbrakes will self-open to full if left unlocked. It high speeds they will open with one hell of a bang unless you apply a great deal of force to prevent this from happening. Most airbrake caps are spring loaded and it is this is what initially opens the brakes, the rest is aerodynamic.

PM
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Old 9th Oct 2017, 23:11
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It was a deliberate release, he obviously forgot the check list and didn't lock the brakes, did the tug wave him off?, because he was not climbing ?. If not why release at that height, he hit the trees almost immediately. If the tuggie thought he was so low that he might hit the trees he may have dumped him, with brakes closed he would have made the field to the right.
Should be compulsory viewing for all pilots.
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Old 9th Oct 2017, 23:38
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A small whistle or air-driven siren built in to the top of the airbrake blade might make the pilot more aware of them being open.
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Old 10th Oct 2017, 10:46
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Two points from my perspective. On the couple of occasions that I've launched with the airbrakes unlocked I've happily noticed pretty quickly and got them shut without disaster. But the underlying reason for taking off with brakes unlocked on both occasions was a delay in launching, and a presumption that I'd already checked the brakes when the launch sequence resumed. That's why I now teach Bloggs to open the canopy when there's a launch delay, because "Canopy" precedes Brakes in the pre-flight checks, and the canopy open is a pretty good clue that you need to do brakes again.
Also, if the tuggy notices that the glider has its brakes open (which he probably will, as he's now dragging a large garden shed into the air) he has a couple of ways to signal this to the glider pilot. One is to signal with rudder reversals, but if you're low and slow, the last thing you want is an asymmetric stall, so they may not feel inclined to do this. Of course the other way is to use radio, assuming the glider pilot has remembered to switch the thing on and is on the same frequency. But in the final analysis tuggy may revert to self-preservation and release at his end, and the glider pilot will now be pushing the rope.
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Old 10th Oct 2017, 11:13
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Been there!

I was the tuggie for the day. Flying my 150hp Supercub at Shenington.

Had been taking off crosswind on the longer run. They asked me to use the shorter run, directly into wind for the next takeoff, which meant that we HAD TO TAKE OFF ACROSS the runway in use by everybody else.

So we lined up, and had to wait for Everybody Else to takeoff, land, or whatever. And I was getting annoyed.

NEVER GET ANNOYED!

At last it was our turn, the K13 behind me was slow to roll. Was my engine delivering enough power? I glanced at the dials....all OK. Sounded OK. I looked in my rear view mirror - tugs have a rear view mirror so you can keep an eye on the glider.

Sure enough, the airbrakes on the twoseater K13 were wide open!

I was dragging a shed. The earth bank in front was getting too close for comfort. Despite the engine doing its best, my speed got slower.

What is the stalling speed for a combination like that? I reckon we had about 50 mph at very best estimate. So I carried on over the earth bank, only just. And carried on dragging the shed by now about 45 mph, and not happy at all, so at 500 feet I DUMPED THE GLIDER.

By that height they should easily have been able to return to the airfield, but only if they noticed the open brakes and did something about them.

Tuggies very seldom dump a glider. I've only done it 3 times. When I turned around, the K13 had vanished. Where did it go? People were running around on the ground like something urgent had happened.

The instructor and student in the K13 had NOT NOTICED AT ALL the open airbrakes. They simply plonked the glider in the nearest field, and then realised they were still wearing the towrope! No damage, no injury.

A learning experience altogether. I resolved never again to accept towing across runway in general use. I also resolved if I was upset to NOT PROCEED with the tow.

The tug pilot is responsible for the combination. But if the glider has the airbrakes open, most tugs have enough grunt to drag it up anyhow. We were marginal, and towing across an eight foot earthen bank. The only good news it was directly into the wind for the day.

Last edited by mary meagher; 11th Oct 2017 at 08:55.
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Old 10th Oct 2017, 11:31
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MODS,
I know this pilot. He has not given his consent for the dissemination of this video. His family are distressed by it being posted on Facebook and are taking steps to have it removed. Perhaps it would be wise to discontinue this thread. I understand that his club had asked if they could use the video for training purposes and, being the decent person he is, he agreed. But he did not agree for it to be published or passed around for people to post on social media.
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Old 10th Oct 2017, 15:03
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Ouch.... I was desperately willing him to pull the bung - I'm sure he won't do that again! Lucky that he's around to regret sharing the video - a solid reminder for us all not to take things for granted.

Speedy recovery to you, sir.
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Old 10th Oct 2017, 17:29
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Had the video not been 'shared' all we would have seen or indeed heard is a bare two line summary of the accident published in 6 months plus it would have disappeared anonymously into the general accident statistics for 2017 published sometime in 2018.

By which time no one will care, everyone will have forgotten and nothing would have been learn't....
Notice how it is not been mentioned at all on UK glider pilot dot net: clearly not a suitable discussion subject.
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Old 10th Oct 2017, 17:30
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Rough Ground or Bounce Can Unlock Spoilers

On an early flight in a Junior, the first behind a Pawnee, I ballooned on takeoff. The [slightly over] correction bounced me off the ground, but no more oscillations.

Once we were both in the air, I noticed the handling was poor and saw the spoilers had come out - and promptly closed them.

We train devout adherence to the checklist, but we do not train for the rare but humanly inevitable times the spoilers come out or the canopy comes unlatched.

I saw an L-33 written off when the pilot would not let go of the unlatched side opening canopy to use spoilers on short final. He used sideslip to get down and in the moment did not realize that a sideslip against the opening would have held the canopy down hands free.

I saw a Jantar with a shattered canopy make a dodgy circuit to a cross runway when there were perfectly good fields ahead.

With a CG hook, I keep a hand on the release for the entire duration of the launch except when I have to change flaps.
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