Hypothetical Scenario #1 - Urgent Action required

On Wednesday, February 5, 2014 11:19:04 PM UTC-5, OneTango wrote:
This is a voluntary pop quiz. You're circling in a 30 degree left bank at 3000 AGL. You hear a thunk and the glider enters a spin. Your practiced spin recovery technique does not work in the usual amount of time. You look in the direction of the thunk and see that the left spoiler is full open, you confirm that the spoiler control handle is in the fully closed position. A quick look confirms that the right spoiler is full closed. What do you do next? Why did the left spoiler pop open. What just happened? To derive the full benefit of this exercise, you might respond to this thread with your answer before looking at any of the other replies. My hypothetical solution and explanation follows as the next comment.

Dive brake became uncontrollable. It does not matter why.
Apply opposite rudder and unload the wing by neutralizing the stick in pitch while also neutralizing aileron. Open other dive brake to balance assymetrical drag that is helping add yaw in the spin.
Upon recovery, determine if the glider is controllable with one brake open. It will be in any case I would expect.
Get to landable place with one brake out(less drag than 2).
Fly a bit tighter pattern to allow for what is effectively 1/2 brake.
Go to full brakes from high final to balance and allow "normal" landing.
UH

I've been thinking this would be a fun scenario to practice on a BFR, to give the student (who will surely appreciate it) practice at handling an emergency that really isn't an emergency.

When the student checks airbrakes on his/her downwind checklist (what downwind checklist? Ah, on the second flight then!), I grab the airbrakes and say "the airbrakes just stuck open." And shut up. Now the student's job is to quickly plan a full airbrake plus slip pattern. It's not a real emergency, because we can always close the airbrakes.

Has anyone tried this? UH, font of all wisdom on such things?

John Cochrane

On Thursday, February 6, 2014 11:01:32 AM UTC-5, wrote:
I've been thinking this would be a fun scenario to practice on a BFR, to give the student (who will surely appreciate it) practice at handling an emergency that really isn't an emergency. When the student checks airbrakes on his/her downwind checklist (what downwind checklist? Ah, on the second flight then!), I grab the airbrakes and say "the airbrakes just stuck open." And shut up. Now the student's job is to quickly plan a full airbrake plus slip pattern. It's not a real emergency, because we can always close the airbrakes. Has anyone tried this? UH, font of all wisdom on such things? John Cochrane

Stuck or frozen open dive brake condition is part of our pre solo training. It does happen in the Winter.
UH

On Thursday, February 6, 2014 10:54:09 AM UTC-6, wrote:
On Thursday, February 6, 2014 11:01:32 AM UTC-5, wrote: I've been thinking this would be a fun scenario to practice on a BFR, to give the student (who will surely appreciate it) practice at handling an emergency that really isn't an emergency. When the student checks airbrakes on his/her downwind checklist (what downwind checklist? Ah, on the second flight then!), I grab the airbrakes and say "the airbrakes just stuck open.." And shut up. Now the student's job is to quickly plan a full airbrake plus slip pattern. It's not a real emergency, because we can always close the airbrakes. Has anyone tried this? UH, font of all wisdom on such things? John Cochrane Stuck or frozen open dive brake condition is part of our pre solo training. It does happen in the Winter. UH

Recover from the spin, land, post ship on wings and wheels.

All very good answers. I thought someone might mention direction of turns by now. With the one airbrake open it may be very hard to raise that wing again in a turn if it is the low side wing. Wouldn't it be wise to fly the pattern with the spoiled wing on the high side of the turns? ie - if your right airbrake is open you would want to do a left hand pattern? I would hate to get to pattern altitude and discover I can't raise my wing with the broken airbrake out after making the first turn...

Bruno -B4

On Thursday, February 6, 2014 11:09:23 AM UTC-6, wrote:
All very good answers. I thought someone might mention direction of turns by now. With the one airbrake open it may be very hard to raise that wing again in a turn if it is the low side wing. Wouldn't it be wise to fly the pattern with the spoiled wing on the high side of the turns? ie - if your right airbrake is open you would want to do a left hand pattern? I would hate to get to pattern altitude and discover I can't raise my wing with the broken airbrake out after making the first turn...

No problem - just open the other airbrake long enough to get around the turn, then close if needed.

Kirk
66

Opening the functioning airbrake makes the ship symmetrical again. You've
done an "airbrake stuck open" pattern, haven't you?


wrote in message
...
All very good answers. I thought someone might mention direction of turns
by now. With the one airbrake open it may be very hard to raise that wing
again in a turn if it is the low side wing. Wouldn't it be wise to fly the
pattern with the spoiled wing on the high side of the turns? ie - if your
right airbrake is open you would want to do a left hand pattern? I would
hate to get to pattern altitude and discover I can't raise my wing with the
broken airbrake out after making the first turn...

Bruno -B4

A thought not mentioned -- is the "spin" really a spin? With one spoiler out, are you not just in an uncommanded turn, or spiral dive? Spiral dive vs. spin confusion is suggested in a few recent accident reports, and several manuals say spins will turn in to spiral dives on their own. Proper recovery depends on what is really happening.

John Cochrane

On Thursday, February 6, 2014 11:54:09 AM UTC-5, wrote:
On Thursday, February 6, 2014 11:01:32 AM UTC-5, wrote:

Stuck or frozen open dive brake condition is part of our pre solo training. It does happen in the Winter.

UH

Yup. Both stuck open and stuck closed patterns are in the syllabus for both initial and recurrent training at my club that does ab initio training. I also go over this in BFRs. FWIW, stuck closed (maybe never connected during assembly) is actually a much bigger issue in a typical, modern glass ship.

P3

On Thursday, February 6, 2014 12:10:39 PM UTC-5, Papa3 wrote:
On Thursday, February 6, 2014 11:54:09 AM UTC-5, wrote:

On Thursday, February 6, 2014 11:01:32 AM UTC-5, wrote:



Stuck or frozen open dive brake condition is part of our pre solo training. It does happen in the Winter.



UH



Yup. Both stuck open and stuck closed patterns are in the syllabus for both initial and recurrent training at my club that does ab initio training. I also go over this in BFRs. FWIW, stuck closed (maybe never connected during assembly) is actually a much bigger issue in a typical, modern glass ship.



P3

I got a PM asking why stuck closed is a bigger issue in the pattern. Briefly, because a) modern ships are not all that easy to "dirty up" with a slip and b) they will float forever in ground effect, especially with any excess speed. I routinely practiced slipping my LS4 and LS8 to landings (note: POH has a specific caution on doing this with divebrakes deployed), and it requires pretty aggressive use of rudder and a reasonable amount of "touch". I also managed to float almost the entire length of Mifflin airport (over 4,000 feet) one day with zero spoilers from about 10 feet and 55kts. That's like 400:1 including the tradeoff of 15kts or so to get down to a 40kt touchdown. For someone not prepared for the float, they could easily end up trying to force the glider on at a higher speed - see "flopping fish syndrome" and "broken gear bulkhead".

P3