On Wednesday, February 5, 2014 8:42:13 PM UTC-8, OneTango wrote:
This is my best guess. I have no idea if it is correct.



What do you do next?



Use the spoiler handle to open the right spoiler to match the left.



Follow my practiced spin recovery technique and return to level flight with both spoilers fully open.



Decide whether to land or bail out.



If there is a place that I can land with both spoilers fully open. Do that.



If I cannot make it to a field with both spoilers open, quickly determine if it is possible (and if there is less sink) to fly with one spoiler open and one spoiler closed. If it is possible, decide whether to try it or bail out.



Why did the left spoiler pop open?



When the push rod that controls the spoilers locks past the detente, it is under compression and it is designed to bend slightly. Due to a manufacturing defect, the bent aluminum push rod rubs against the fiberglass where it passes through a wing rib (hole is not in exactly the right place or hole is not the right shape or size). Over time, the glass wing rib saws through the aluminum pushrod. At a certain point the pushrod buckles and breaks.. The spoiler pops open.

Your scenario #1 actually did happen in a DG-400 at Truckee about 25 years ago. One spoiler needed to be adjusted slightly, so the (non mechanic) pilot gave the quick disconnect fitting a half turn in. Under positive G force the fitting was now trying to pull away from the ball, rather than being forced into to ball. At about 4000 feet AGL, one spoiler popped full open. The pilot correctly assessed the situation and pulled the other spoiler open. Having plenty of altitude, he decided to enter the pattern to the normal glider runway (19) at 2000 feet..........thinking that extra altitude is always good, right? The extra altitude meant he had to fly farter down-wind to get rid of his excess altitude, turned final into some wind and didn't make it back to the runway! Landing short of 19 at Truckee means you hit a cliff.

If you are faced with this situation (one spoiler open), Put the ship in the middle of the longest runway available!
JJ