There was an incident in 2011 where an aircraft was being flown in an aerobatic display and started to lose the fabric from its upper wing, causing a loss of lift. The pilot was able to make an emergency landing without injury to himself or further damage to the plane.
The incident report (with photos) can be seen here:
What is meant by keeping the aircraft in slightly negative G? How is this “constant negative-G configuration” set up? If there is a technique that reduces stall speed and allows a plane to be put down at low speed in a short field, why is this technique not more widely known and taught for use in emergency situations like this one?
I believe that means he was ‘pushing’ the plane down rather than letting it drift. Positive Gs happen when you pull up, negative when you nose over.
By coming in slightly steep/fast, he knew the plane would maintain some lift and not stall out.
Short answer:
Not actually Negative G but LESS than the normal 1 G of level flight.
In other words, descending a bit faster than than normal for that airspeed.
I don’t think I am expressing it correctly.
Long answer:
Remember the cautions you were taught about getting to tight turning from Base leg to Final?
There is a way, at least with some of the planes I have flown, that if you are high and need to make a short approach from a close in downwind to the end of the runway you can trade excess speed and/or altitude by unloading the wings by relaxing back pressure, steeping up the turn and increasing the decent rate.
You do not go negative, at least I never had to take it that far, but doing that maneuver, the aircraft will be at less than one G until you straighten out on short Final…
Can you visualize that?
Never had to do it in a single engine Cessna. I have routinely done this in C-310, AeroStar, Globe Swift, Comanche, and a few other high wing loaded planes by design or by load. ( think check hauling at night )
With his wing deformed but still with a lower surface he was similar to a heavy loaded aircraft & the control problems just made it much worse. Had some real bad air flow going on. He did better than a large majority of pilots could have done IMO. Way better than me I think.
Thank you all for your explanations, all of which make some sense.
However I still don’t understand. Pushing the nose down will generally result in a higher airspeed. But in the quoted excerpt from the incident report, it is clearly implied that the so-called “negative-g” descent was slower than a normal descent (and in fact slower than the 1-G stall speed).
By flying in this configuration, he was able to fly the approach at 40 knots, which has obvious advantages in terms of putting the plane down in a short field.
So I don’t think they are talking about just pushing the stick forward - there’s something I’m missing.
I can’t make sense of it in a way that makes it seem like a good idea. I agree that there is no way it was actually negative g, but even allowing for it to be between 0 and 1 g I can’t make sense of it.
Keep in mind that this is from the pilot interview so it represents what the pilot said he did rather than what he actually did. I don’t mean any disrespect but he is a fallible human being and you might be surprised by how little some pilots know about flying theory (I’ve had one try and tell me how different his tiger moth felt flying in a strong tail wind).