G-LOC
G-LOC
Hi all
I had an odd experience at the weekend while flying aerobatics, and would appreciate any input the experts are able to give.
I was flying a fairly basic sequence. I came out of a reverse half-cuban (45 degree climb, roll to inverted on climb, pull through as for a loop to horizontal flight) where I'd pulled about 4 G, with no feeling of grey-out or black-out. I levelled out, and about 2 seconds later went out like a light. Came-to about five seconds later. Initially vision returned, but I couldn't move my limbs for another second or so. I experienced ringing / buzzing noises in my ears, and my legs were shaking for a few seconds. Thereafter I felt fine, regained control (aircraft had settled into a gentle turn, level flight). I canned the rest of the sequence and landed immediately. Felt fine afterwards, although a little shaken. Looking at the recording G-meter, I'd pulled -2/+5 for the entire sequence.
I spoke to some of the experienced pilots and the field, and they suggested I'd simply "overcooked" the sequence, and was possibly not G-fit. All said they'd had similar experiences over the years, and I simply needed to improve fitness levels.
I do still have concerns over the incident. My real concern is that the incident ocurred after the G's had been released. I've felt grey-out before (never gone to complete black-out), and have pulled +8 / -4 before without losing it.
I'm in general good health, although I do feel run-down and stressed, mainly due to work pressures. A medical friend has suggested that I might be suffering from iron deficiency, and am generally unfit. I am going for some blood tests in the next few days to see if anything can be picked up. My general fitness has deteriorated, I now notice that I get short of breath pulling the plane out of the hangar.
Would a lack of general fitness cause the events describe? Can it be rectified by diet and exercise? And can any permanent damage result from the incident?
I had an odd experience at the weekend while flying aerobatics, and would appreciate any input the experts are able to give.
I was flying a fairly basic sequence. I came out of a reverse half-cuban (45 degree climb, roll to inverted on climb, pull through as for a loop to horizontal flight) where I'd pulled about 4 G, with no feeling of grey-out or black-out. I levelled out, and about 2 seconds later went out like a light. Came-to about five seconds later. Initially vision returned, but I couldn't move my limbs for another second or so. I experienced ringing / buzzing noises in my ears, and my legs were shaking for a few seconds. Thereafter I felt fine, regained control (aircraft had settled into a gentle turn, level flight). I canned the rest of the sequence and landed immediately. Felt fine afterwards, although a little shaken. Looking at the recording G-meter, I'd pulled -2/+5 for the entire sequence.
I spoke to some of the experienced pilots and the field, and they suggested I'd simply "overcooked" the sequence, and was possibly not G-fit. All said they'd had similar experiences over the years, and I simply needed to improve fitness levels.
I do still have concerns over the incident. My real concern is that the incident ocurred after the G's had been released. I've felt grey-out before (never gone to complete black-out), and have pulled +8 / -4 before without losing it.
I'm in general good health, although I do feel run-down and stressed, mainly due to work pressures. A medical friend has suggested that I might be suffering from iron deficiency, and am generally unfit. I am going for some blood tests in the next few days to see if anything can be picked up. My general fitness has deteriorated, I now notice that I get short of breath pulling the plane out of the hangar.
Would a lack of general fitness cause the events describe? Can it be rectified by diet and exercise? And can any permanent damage result from the incident?
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Shortness of breath during limited exercise could be indicative of some blockage in the heart.. ischemia..
Second thing is G-tolerance builds up and if you have not been pulling a lot, doesn't take a lot to put you out.
Finally, "And can any permanent damage result from the incident?"
Yep.. if it happens close to the ground and you don't have enough altitude to keep air between you and the dirt.
Get a good physical.
Second thing is G-tolerance builds up and if you have not been pulling a lot, doesn't take a lot to put you out.
Finally, "And can any permanent damage result from the incident?"
Yep.. if it happens close to the ground and you don't have enough altitude to keep air between you and the dirt.
Get a good physical.
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This may be related to the actual total change of G - for example, the Hawk aeros pilot at RAF Valley some years ago tried as part of his display practice an inverted pass, -2.5G pushup to 60 deg nose up, then a 5G pull back through the vertical to level. After landing, he stated that he felt "weird" immediately after completing the 5G pull (trembling limbs, visual disturbances etc). This was in the early days of G-LOC knowledge and the Aeromed guys thought that it was the actual total transition from -2.5 to +5G that did it; i.e. a total G change of 7.5G, with the effects being magnified due to the rapid transition from negative to positive G.
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I'm wondering about any after effects of g-loc in the subsequent few days.
A pilot experiences g-loc (or more likely a-loc) in that he remembers coming out of a sustained 180 pull at about +5g from a down line, not "entirely sure" of what's happening for a few seconds but with the a/c now straight and level at least. It is of course a symptom of these states that the pilot can have no recollection of the g-induced problem!
No aerobatics in the previous 18 months apart from half a dozen sub 4g gentle loops, stall turns etc. a week before i.e. no build up of g tolerance and lost whatever he used to have.
The pilot then reports light headedness for the next couple of days - nothing that deters him from from most normal daily activity, but feeling certainly like he should not fly. The only other symptom reported was a little of the "squirts" 36 hours later.
Is there a longer-term (i.e. A few days worth) of symptoms associated with overdoing the g? Or is is perhaps another related issue such as dehydration or a slight cold/fever exasperated by flying outside of one's curent g tolerence?
A pilot experiences g-loc (or more likely a-loc) in that he remembers coming out of a sustained 180 pull at about +5g from a down line, not "entirely sure" of what's happening for a few seconds but with the a/c now straight and level at least. It is of course a symptom of these states that the pilot can have no recollection of the g-induced problem!
No aerobatics in the previous 18 months apart from half a dozen sub 4g gentle loops, stall turns etc. a week before i.e. no build up of g tolerance and lost whatever he used to have.
The pilot then reports light headedness for the next couple of days - nothing that deters him from from most normal daily activity, but feeling certainly like he should not fly. The only other symptom reported was a little of the "squirts" 36 hours later.
Is there a longer-term (i.e. A few days worth) of symptoms associated with overdoing the g? Or is is perhaps another related issue such as dehydration or a slight cold/fever exasperated by flying outside of one's curent g tolerence?
