Osh Midair

Oshkosh Heli/Gyro Fatal Mid-Air Thread


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So it's very likely the two gyro impacts were from two blades of the helicopter.
Perhaps, but you can't assume consecutive blade passes did all the destruction for the purpose of computing closure rate.

You have no way of knowing how many blades passed through without a major impact in between the two blade passes that did the major damage, and that makes computing the closure rate from rotor rpm impossible. In really simple terms, you can't distinguish, for example, a "whack - whack" sequence from a "whack-miss-miss-whack" sequence from looking at the witness marks, and the difference between those two cases for the deduced closure rate is a rather large factor of two.

Computing the closure rate requires more data than rpm and impact separation distance.
 
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Perhaps, but you can't assume consecutive blade passes did all the destruction for the purpose of computing closure rate.

You have no way of knowing how many blades passed through without a major impact in between the two blade passes that did the major damage, and that makes computing the closure rate from rotor rpm impossible. In really simple terms, you can't distinguish, for example, a "whack - whack" sequence from a "whack-miss-miss-whack" sequence from looking at the witness marks, and the difference between those two cases for the deduced closure rate is a rather large factor of two.

Computing the closure rate requires more data than rpm and impact separation distance.
Agreed more data is needed.

Here is another another data point that puts the convergence rate within range of my previous estimate of 48+ mph.

2.0 seconds prior to collision they were 8 gyro lengths apart
1.0 seconds prior to collision they were 4 gyro lengths apart

Assuming the gyro 16.5ft nose to tail, we're looking at a convergence rate of 66 ft/s = 45mph
 
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...Just to qualify my comments I own two rotorways and worked for the company so I am very familiar with the helicopter.

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David: Then you are well-qualified to answer the question: What is the rotorblade rotation of the Rotorways? (Viewed from above)

The big chunk missing from that rotorblade's aft (trailing edge) looks like a shark bite. I'm wondering if the ELA prop buzz-sawed* it's way through the trailing portion of that rotorbade on it's way prior to taking out the ELA's mast section...

*The prop turning @ a much higher rate of rotation than the rotors do.
 
David: Then you are well-qualified to answer the question: What is the rotorblade rotation of the Rotorways? (Viewed from above)

The big chunk missing from that rotorblade's aft (trailing edge) looks like a shark bite. I'm wondering if the ELA prop buzz-sawed* it's way through the trailing portion of that rotorbade on it's way prior to taking out the ELA's mast section...

*The prop turning @ a much higher rate of rotation than the rotors do.
From above the rotorway turns clockwise.

That's my guess on the shark bite too. It won't be too hard for NTSB to determine with witness marks and residue.

There's plenty for the NTSB to put together a very clear picture.
 
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Airspeed can be fairly accurately determined by video frame rate and looking at the known length of one of the aircraft to see how many frames it takes to traverse one aircraft length.
This could possible partially validate the multiple rotor strike/speed theory.
 
Airspeed can be fairly accurately determined by video frame rate and looking at the known length of one of the aircraft to see how many frames it takes to traverse one aircraft length.
This could possible partially validate the multiple rotor strike/speed theory.
That's exactly what I did.
Here's another rough data point that puts the convergence rate within range of my previous estimate of 48+ mph.

2.0 seconds prior to collision they were 8 gyro lengths apart
1.0 seconds prior to collision they were 4 gyro lengths apart

Assuming the gyro 16.5ft nose to tail, we're looking at a convergence rate of 66 ft/s = 45mph minimum. If the convergence to the helicopter is more or less than 90° from the axis of the helicopter path. Then the airspeed of the Gyro only goes up.
IMG_9884.jpgIMG_9885.jpgIMG_9883.jpg
 
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When there are 4 planes in quick sequence in that pattern letting the lead Heli to do anything but land and clear to the side normally is downright ignorant. Should have never been allowed. You want to fuel up. Do it after. It isn’t an emergency.
The point I think, is that there should never have been 4 planes so close together in the first place as the previous post demonstrates. Recommended pattern speed was 50 Kts. The runway was clear, the lead aircraft stated his intention to land, was cleared to do that, Nothing was incorrect about that. The bunching together however was a major factor
Honestly airshow patterns are not a place for any instruction or familiarity training. It can never be done safely. The pilot needs to pay full attention to outside and what he has to do. All the talk from passengers is highly distracting. Been there and done that.
Agreed.
rAlso it really is dumb to not give the second ELA pilot proper full briefing and tell him to follow first ELA because in anything out of the ordinary like this, that pilot would be hesitant to go around and do a full circuit again.
As I stated, the ELA pilot, was given a second individual proper full briefing, after the, main briefing when it was suggested he follow the first ELA who was familiar. A360 for spacing is a method to increase spacing in the pattern that has been used. The pilot who made that decision was obviously not aware of how close behind his traffic was, The pilot behind obviously did not keep his eyes on his preceding traffic.

As you, and all of us can say, a rapid sequence of events, that went into the culmination of a tragic event.
 
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The point I think, is that there should never have been 4 planes so close together in the first place as the previous post demonstrates. Recommended pattern speed was 50 Kts. The runway was clear, the lead aircraft stated his intention to land, was cleared to do that, Nothing was incorrect about that. The bunching together however was a major factor

Agreed.

As I stated, the ELA pilot, was given a second individual proper full briefing, after the, main briefing when it was suggested he follow the first ELA who was familiar. A360 for spacing is a method to increase spacing in the pattern that has been used. The pilot who made that decision was obviously not aware of how close behind his traffic was, The pilot behind obviously did not keep his eyes on his preceding traffic.

As you, and all of us can say, a rapid sequence of events, that went into the culmination of a tragic event.

Ok. So he was given a full briefing. I have never seen anyone do a 360 at Red Barn at Oshkosh in a decade. I have no idea what the briefing entailed this year but you are supposed to just do a pass and go around.
 
The helicopter's rotor contacting the base of the gyro's mast indicates that the gyro was at a slightly higher altitude than the helicopter at the point of impact. It's hard to tell whether the gyro was at the same altitude or descending. It's less likely that the gyro was increasing in altitude. IF it was descending it would be even harder to have seen the helicopter.

IF this true then FAR 91.113 (g) Right-of-way rules applies
(g) Landing. ... When two or more aircraft are approaching an airport for the purpose of landing, the aircraft at the LOWER altitude has the right-of-way, ...

IF they are on the same altitude the aircraft to the right (helicopter) has the right of way
FAR 91.113 (d) Converging. When aircraft of the same category are converging at approximately the same altitude (except head-on, or nearly so), the aircraft to the other's RIGHT has the right-of-way.

IF the gyro was trying to over take the helicopter then the helicopter has the right of way.
FAR 91.113 (f) Overtaking. Each aircraft that is being OVERTAKEN has the right-of-way and each pilot of an overtaking aircraft shall alter course to the right to pass well clear.
I'm surprised there has been no comments on these three FAR's relevant to right of way.
 
I'm surprised there has been no comments on these three FAR's relevant to right of way.
Giving right of way assumes that at least one of the aircraft is aware that the other is there, which doesn't seem to be the case here.
If the accident was caused by one aircraft intentionally trying to get in front and "cut off" the other, then this would certainly apply.
I can't imagine any pilots getting this close, knowing the other is there and thinking "that guy should be turning soon, because I have the right of away"
 
Giving right of way assumes that at least one of the aircraft is aware that the other is there, which doesn't seem to be the case here.
If the accident was caused by one aircraft intentionally trying to get in front and "cut off" the other, then this would certainly apply.
I can't imagine any pilots getting this close, knowing the other is there and thinking "that guy should be turning soon, because I have the right of away"
Very true. See and avoid is a pre-requisite to yielding.

But that doesn't mean the right-of-way rules don't apply. In a car accident telling the officer that you didn't see the other doesn't exempt you from the rules of the road.
 
Once again…… helicopters and gyroplanes should NOT have been allowed in the show pattern at the same time……helicopters mostly slow to 0 airspeed to land and most were doing quick stops to hover for the crowds…….really screws up the faster moving traffic behind that can’t hover. I was watching and surprised it was going on.
Tragic accident….but that is exactly what it was….an accident.
Let’s learn from it…… let’s modify procedures…..let’s make the tragic loss of life actually mean something and improve safety for future shows. Let’s not try to find the “bad guy” in all this……there were no “bad guys”……just a bunch of people who shared this love we have for flight.
 
But every licensed pilot is supposed to know them already.
 
But every licensed pilot is supposed to know them already.
Supposed to. But apparently not all do. It doesn't hurt to bring it up in case someone finds himself in any of those situations it would be good to know. Very relevant to the small pattern at the UL KOSH field.
 
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One would hope that converging and overtaking right of way rules would be irrelevant when people are following each other around the pattern.
 
One would hope that converging and overtaking right of way rules would be irrelevant when people are following each other around the pattern.
it was no longer following when the gyro initiated the 360.

neither was it following around the pattern when the impact from the side happened at 45 mph.
 
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