NTSB F-16 & Cessna 150 midair preliminary report

[son_of_flubber]

http://www.ntsb.gov/_layouts/ntsb.aviation/GeneratePDF.aspx?id=ERA15FA259A&rpt=p

[Vaughn]

On 7/18/2015 8:40 PM, son_of_flubber wrote:
> http://www.ntsb.gov/_layouts/ntsb.aviation/GeneratePDF.aspx?id=ERA15FA259A&rpt=p
>
To me, this is the crucial passage:
"At 1100:49, the radar target of the F-16 was located 1/2 nautical mile
northeast of the Cessna, at an indicated altitude of 1,500 feet, and was
on an approximate track of 215 degrees. At that time, the Cessna
reported an indicated altitude of 1,400 feet, and was established on an
approximate track of 110 degrees. At 1100:52 the controller advised the
F-16 pilot, "traffic passing below you 1,400 feet." "

I find transponder-reported altitudes to be pretty notoriously
inaccurate in general. So it seems to me that these two planes
indicating only 100 feet apart (but only reporting their altitudes in
100 feet increments) should have been considered at the SAME altitude.

With my PCAS, I consider +/- 400 to be the same altitude.

[Dan Marotta]

I was a bit stunned by the apparent lackadaisical behavior on the part
of both the F-16 pilot and the controller. Advice to turn should be
acted on immediately in a conflict situation. From the writeup it
seemed that neither the pilot nor the controller showed any concern
about such a close encounter. Of course that could simply be that the
printed word can't convey stress or tone in a voice.

Also notable is the fact that, had the F-16 pilot /_not_/ turned when he
did or /_had_/ turned when instructed, the collision would likely not
have occurred.

Vaughn, I agree with you on the PCAS altitude. My last conflict was
noted as -300 ft and, when I spotted the aircraft, it was about 100 ft
above my altitude.

On 7/19/2015 8:52 AM, Vaughn wrote:
> On 7/18/2015 8:40 PM, son_of_flubber wrote:
>> http://www.ntsb.gov/_layouts/ntsb.aviation/GeneratePDF.aspx?id=ERA15FA259A&rpt=p
>>
>>
> To me, this is the crucial passage:
> "At 1100:49, the radar target of the F-16 was located 1/2 nautical
> mile northeast of the Cessna, at an indicated altitude of 1,500 feet,
> and was on an approximate track of 215 degrees. At that time, the
> Cessna reported an indicated altitude of 1,400 feet, and was
> established on an approximate track of 110 degrees. At 1100:52 the
> controller advised the F-16 pilot, "traffic passing below you 1,400
> feet." "
>
> I find transponder-reported altitudes to be pretty notoriously
> inaccurate in general. So it seems to me that these two planes
> indicating only 100 feet apart (but only reporting their altitudes in
> 100 feet increments) should have been considered at the SAME altitude.
>
> With my PCAS, I consider +/- 400 to be the same altitude.

--
Dan Marotta

[kirk.stant]

On Sunday, July 19, 2015 at 10:33:58 AM UTC-5, Dan Marotta wrote:

> "At 1100:49, the radar target of the F-16 was located 1/2 nautical
> mile northeast of the Cessna, at an indicated altitude of 1,500
> feet, and was on an approximate track of 215 degrees. At that
> time, the Cessna reported an indicated altitude of 1,400 feet, and
> was established on an approximate track of 110 degrees. At 1100:52
> the controller advised the F-16 pilot, "traffic passing below you
> 1,400 feet." "
>

So, the Cessna was pretty close to the beam, and therefore may not have shown up on the F-16s radar.

It almost sounds like both the controller and the Viper driver expected the other to take the appropriate action - neither took full responsibility for preventing the possible collision, expecting the other to do it!

So much for a transponder ALONE being the solution to midairs...

And until installing ADS-B Out in a certified airplane is a LOT cheaper, what are the chances that that Cessna owner would have bothered?

Would ADS-B in have provided timely warning to the Cessna of the approach of the F-16? As I understand it, since neither the Cessna or the F-16 had ADS-B out, the Cessna would not have received any traffic info from the ADS-B ground stations.

Thanks, FAA, for this idiotic implementation - withholding traffic data as an incentive to equip with ADS-B out!

Dual band ADS-B receivers SHOULD receive both weather AND all traffic! That would probably guarantee that just about everything flying would at least get traffic info!

Kirk
66

[Ramy[_2_]]

A note about transponder altitude inaccuracy. I also noticed significant inaccuracy when I used the Zaon MRX but once I switched to PowerFlarm I found mode C reported altitudes much more accurate, so I suspect the significant inaccuracy that Dan noted is due to MRX error, not necessarily transponder error.

Ramy

[Darryl Ramm]

Ramy > wrote:
> A note about transponder altitude inaccuracy. I also noticed significant
> inaccuracy when I used the Zaon MRX but once I switched to PowerFlarm I
> found mode C reported altitudes much more accurate, so I suspect the
> significant inaccuracy that Dan noted is due to MRX error, not
> necessarily transponder error.
>
> Ramy

You may get larger MRX errors if the glider does not have a local
transponder (that is being interrogated and seen by the MRX)...if it does
the MRX will use the transponder's transmitted altitude instead of it's
internal pressure sensor--which can be affected by cockpit ventilation.
With the number of issues that I believe Ramy had with his MRX maybe it was
not properly identifying the local transponder.

[[email protected]]

Controller appears to have given an abundance of information to the F-16 pilot. The F-16 pilot, in one of the most highly maneuverable aircraft ever made, did virtually nothing with it to provide margin. huh.

[Dan Marotta]

That could be the case, however... The MRX PCAS uses an internal
barometric sensor in the absence of an own ship's transponder. I've
observed its startup and noted that it initially reports a transponder
code of 3707 or some other nonsense, after my transponder is turned on
and begun replying to interrogations, the PCAS with show a TX code of
1200 and, finally, 1202 to which my Trig is set to reply.

I don't know what the required Mode C/S accuracy is below FL180, but if
it's +/- 200 feet, then you could occasionally see a 400' error. That or
my PCAS lost lock with my Trig, or it's just sloppy. Next time I see an
aircraft on which I've received an alert, I'll check the PCAS for the
transponder code it's using for its calculations. If I gain some
insight, I'll report it here.

On 7/19/2015 11:43 AM, Ramy wrote:
> A note about transponder altitude inaccuracy. I also noticed significant inaccuracy when I used the Zaon MRX but once I switched to PowerFlarm I found mode C reported altitudes much more accurate, so I suspect the significant inaccuracy that Dan noted is due to MRX error, not necessarily transponder error.
>
> Ramy

--
Dan Marotta

[Steve Leonard[_2_]]

On Monday, July 20, 2015 at 10:39:21 AM UTC-5, wrote:
> Controller appears to have given an abundance of information to the F-16 pilot. The F-16 pilot, in one of the most highly maneuverable aircraft ever made, did virtually nothing with it to provide margin. huh.

And if you have two planes, one heading 110 degrees, one heading 260 degrees, the plane heading 110 degrees is reported to be at the 12 o'clock position of the plane heading 260 degrees, why would you tell the plane heading 260 degrees to "Turn left to heading 180 degrees"? This seems to me to be continuing to aim the 260 degree heading plane at the 110 degree heading plane.

It seems like it would have made more sense to turn the F-16 to the right.

And, it could also be read that there would have been no conflict at all had the F-16 pilot not begun a left turn. By my read, he had changed his heading approximately 45 degrees in the direction directed by the controller when the collision occurred. So, if the F-16 pilot had done nothing, there would not have been a collision? Is this how good our ATC radar is? Or was there a controller error that helped facilitate the collision?

Too much Monday Morning Quarterbacking.

[[email protected]]

> Too much Monday Morning Quarterbacking.

hey I'm not the one suggesting the controller should have said go right instead of left. But I'll admit its a fair point.

Bottom line, that first call: traffic, 12 o'clock 2 miles opposite direction - ..close in altitude, is good info and more than a lot of us get when we end up finding ourselves close to another aircraft. It's a shame that was not enough to prevent the accident.

[Steve Leonard[_2_]]

On Monday, July 20, 2015 at 7:33:59 PM UTC-5, wrote:
> > Too much Monday Morning Quarterbacking.
>
> hey I'm not the one suggesting the controller should have said go right instead of left. But I'll admit its a fair point.
>

The MMQ I was talking about was myself, not you. Sorry that it was not clear. Agree, call the traffic. If no visual, change course. Just a terrible tragedy that the change suggested, and the rate at which the change was made managed to drive the two together, instead of further apart.

From the way I read it, if the F-16 pilot had done nothing, there would be nothing to report, as he had changed course by nearly 45 degrees (260 to roughly 215) before the collision occurred.

Steve Leonard

[Dan Marotta]

I wonder, with the F-16's climbing ability, why the pilot didn't change
altitude. I know... Monday morning quarter backing, instrument
approach, and all that, but nobody would be dead and two aircraft
wouldn't have been lost. Only one practice approach...

Why, I remember back in the old days... Seriously, as a student pilot
departing San Antonio, we penetrated the clouds during a "quick climb"
and the controller called traffic 12 o'clock and (I don't recall how
many) miles. I immediately asked for a vector and the controller
replied, "He's too close - it wouldn't matter"!!! The instructor in the
back seat grabbed the stick, shouted, "I got it" and pulled about 5 g,
we broke out of the top of the clouds, just missing the light twin
dodging the cloud tops and apparently not on an IFR flight plan. Ya
gotta do what ya gotta do... I wish I'd thought of the quick pull-up at
the time, but I learned from it.

On 7/20/2015 10:28 PM, Steve Leonard wrote:
> On Monday, July 20, 2015 at 7:33:59 PM UTC-5, wrote:
>>> Too much Monday Morning Quarterbacking.
>> hey I'm not the one suggesting the controller should have said go right instead of left. But I'll admit its a fair point.
>>
> The MMQ I was talking about was myself, not you. Sorry that it was not clear. Agree, call the traffic. If no visual, change course. Just a terrible tragedy that the change suggested, and the rate at which the change was made managed to drive the two together, instead of further apart.
>
> From the way I read it, if the F-16 pilot had done nothing, there would be nothing to report, as he had changed course by nearly 45 degrees (260 to roughly 215) before the collision occurred.
>
> Steve Leonard

--
Dan Marotta

[Ramy[_2_]]

Even in a glider, if you are too close to maneuver left or right, a quick pull up, or a dive, is the fastest way to prevent a midair.

Ramy

[Dan Marotta]

Yup... Only a week ago, I did a quick unload and bottom rudder to avoid
a conflict in a thermal.

On 7/21/2015 10:08 AM, Ramy wrote:
> Even in a glider, if you are too close to maneuver left or right, a quick pull up, or a dive, is the fastest way to prevent a midair.
>
> Ramy

--
Dan Marotta

[Squeaky]

;906668']On Monday, July 20, 2015 at 7:33:59 PM UTC-5, wrote:
Too much Monday Morning Quarterbacking.

hey I'm not the one suggesting the controller should have said go right instead of left. But I'll admit its a fair point.


Agree, call the traffic. If no visual, change course. Just a terrible tragedy that the change suggested, and the rate at which the change was made managed to drive the two together, instead of further apart.

From the way I read it, if the F-16 pilot had done nothing, there would be nothing to report, as he had changed course by nearly 45 degrees (260 to roughly 215) before the collision occurred.

Steve Leonard

I am puzzled as to why the F-16 didn't turn south the first time... Clear call from controller: if traffic not in sight, turn left to 180. That doesn't mean keep looking. I also think, contrary to others, that showed good awareness and concern by ATC. The second follow up call more so. The Viper driver seemed lackadaisical to me, and seemed to think he had time to keep looking... Not what you are supposed to do.

On some other questions, or comments: I would not read too much into the altitude accuracy of Mode C in this case. Couple of reasons. Mode C reports to the nearest 100 ft altitude--so an aircraft at 1449 ft is at 1400 feet for Mode C. Second, the Mode C altitude is updated only when the ATC radar sweeps through the aircraft position the each time. As the C-150 was climbing, he could have been closer to 1600 by the time the next sweep comes around. Heading info can only really be updated sweep to sweep as well, so an aircraft taking off and then planning on heading to MB will have been more dynamic than the occasional radar updates, so take the 110 C-150 heading with a big grain of salt.

The F-16 by the same account was at 1500 feet, though his clearance was to 1600. 100 feet off however is acceptable IFR standards, but not the way we tend to fly. But by Mode C reporting standards he could have been 1450 to 1549 feet high.

I find major problems with the F-16's actions and responses. Not respecting the first turn call was bad. You either see them or you do not. To me, this was clear ATC command under IFR control, I do not see him therefore I have to turn. If I turn under IFR procedures in an F-16, I roll into a 30 degree bank and until I roll out heading 180. This turn was executed late, even delayed after the second call to turn (but this seems more like an educated assumption on my part). So by the time the F-16 began his turn, he might have been better off not turning. Probably had he turned at the first command, no issues either. But in the end game, this is too dynamic a situation for ATC radar to get right at their update rate, hence their procedures--the first call was right--if you do not see him, turn--that much was clear to the controller for an aircraft that just took off and was climbing into the F-16's environment. The second call was late (in ATC requirements, but he was apparently betting that since the F-16 didn't turn, that he was visual with the traffic).

Not a great outcome...

[Charlie M. (UH & 002 owner/pilot)]

On Tuesday, July 21, 2015 at 12:35:47 PM UTC-4, Dan Marotta wrote:
> Yup...* Only a week ago, I did a quick unload and bottom rudder to
> avoid a conflict in a thermal.
>
Dan Marotta

Not saying right or wrong in your case (wasn't there, didn't see it....), but, "for others", keep in mind there "may" be a glider just under your belly!!
While you may have missed one "issue", you may have created another "issue"......

Stated from a comp pilot/CFIG...... just think before acting.... I know time is short at times, but try.

Please?

[Steve Leonard[_2_]]

On Tuesday, July 21, 2015 at 1:43:02 PM UTC-5, Squeaky wrote:
> 'Steve Leonard[_2_ Wrote:
> > ;906668']On Monday, July 20, 2015 at 7:33:59 PM UTC-5,
> > wrote:--
> > Too much Monday Morning Quarterbacking.-
> >
> > hey I'm not the one suggesting the controller should have said go right
> > instead of left. But I'll admit its a fair point.
> > -
> >
> > Agree, call the traffic. If no visual, change course. Just a terrible
> > tragedy that the change suggested, and the rate at which the change was
> > made managed to drive the two together, instead of further apart.
> >
> > From the way I read it, if the F-16 pilot had done nothing, there would
> > be nothing to report, as he had changed course by nearly 45 degrees (260
> > to roughly 215) before the collision occurred.
> >
> > Steve Leonard
>
> I am puzzled as to why the F-16 didn't turn south the first time...
> Clear call from controller: if traffic not in sight, turn left to 180.
> That doesn't mean keep looking. I also think, contrary to others, that
> showed good awareness and concern by ATC. The second follow up call
> more so. The Viper driver seemed lackadaisical to me, and seemed to
> think he had time to keep looking... Not what you are supposed to do.
>
> On some other questions, or comments: I would not read too much into
> the altitude accuracy of Mode C in this case. Couple of reasons. Mode C
> reports to the nearest 100 ft altitude--so an aircraft at 1449 ft is at
> 1400 feet for Mode C. Second, the Mode C altitude is updated only when
> the ATC radar sweeps through the aircraft position the each time. As
> the C-150 was climbing, he could have been closer to 1600 by the time
> the next sweep comes around. Heading info can only really be updated
> sweep to sweep as well, so an aircraft taking off and then planning on
> heading to MB will have been more dynamic than the occasional radar
> updates, so take the 110 C-150 heading with a big grain of salt.
>
> The F-16 by the same account was at 1500 feet, though his clearance was
> to 1600. 100 feet off however is acceptable IFR standards, but not the
> way we tend to fly. But by Mode C reporting standards he could have
> been 1450 to 1549 feet high.
>
> I find major problems with the F-16's actions and responses. Not
> respecting the first turn call was bad. You either see them or you do
> not. To me, this was clear ATC command under IFR control, I do not see
> him therefore I have to turn. If I turn under IFR procedures in an
> F-16, I roll into a 30 degree bank and until I roll out heading 180.
> This turn was executed late, even delayed after the second call to turn
> (but this seems more like an educated assumption on my part). So by the
> time the F-16 began his turn, he might have been better off not turning.
> Probably had he turned at the first command, no issues either. But in
> the end game, this is too dynamic a situation for ATC radar to get right
> at their update rate, hence their procedures--the first call was
> right--if you do not see him, turn--that much was clear to the
> controller for an aircraft that just took off and was climbing into the
> F-16's environment. The second call was late (in ATC requirements, but
> he was apparently betting that since the F-16 didn't turn, that he was
> visual with the traffic).
>
> Not a great outcome...
>
>
>
>
> --
> Squeaky

Completely agree, Squeaky. While the directed left turn may not have been the best, it was a direction that was not followed. The direction was given again, and there is implication of yet another delay. Very poor form on the part of the pilot.

Steve Leonard

[Dan Marotta]

A very good point but, in this case, I was aware of my surroundings.
The G-103 was the only glider other than my own in the immediate area.
He had a better thermal than I did, so I moved over to join from below.
He increased his turn rate just as I was entering, putting us on
possibly conflicting paths. To dodge him I could have: rolled out
slightly and gone under him to the outside of his turn, but that would
have been too close and he would not have seen me; increased my bank
angle and pulled inside his turn, but that would expose my belly and I
would have lost sight of him and, quite frankly, would have been rude;
put the nose down and seek lift elsewhere. Doing the last maneuver I
never lost sight of him until I was speeding away. That sounds like a
lot to consider in a short time but maintaining situational awareness
makes this less of an issue than it might sound like.



On 7/21/2015 5:04 PM, Charlie M. (UH & 002 owner/pilot) wrote:
> On Tuesday, July 21, 2015 at 12:35:47 PM UTC-4, Dan Marotta wrote:
>> Yup... Only a week ago, I did a quick unload and bottom rudder to
>> avoid a conflict in a thermal.
>>
> Dan Marotta
>
> Not saying right or wrong in your case (wasn't there, didn't see it....), but, "for others", keep in mind there "may" be a glider just under your belly!!
> While you may have missed one "issue", you may have created another "issue".....
>
> Stated from a comp pilot/CFIG...... just think before acting.... I know time is short at times, but try.
>
> Please?
>

--
Dan Marotta

[Bob Pasker]

regarding altitude differences, 91.217 requires that the altimeter report pressure altitude correctly within 125 feet. So two aircraft, one reporting FL050 but 125ft high at 5,125 MSL and another reporting FL053, but 125ft low at 5,175 MSL will pass very close to each other, especially if one of them might be an ASH-30 in a level turn.

https://www.law.cornell.edu/cfr/text/14/91.217

[Vaughn]

On 7/22/2015 1:03 PM, Bob Pasker wrote:
> regarding altitude differences, 91.217 requires that the altimeter report pressure
>altitude correctly within 125 feet. So two aircraft, one reporting
FL050 but 125ft
>high at 5,125 MSL and another reporting FL053, but 125ft low at 5,175
MSL will pass
very close to each other, especially if one of them might be an ASH-30
in a level turn.
>
> https://www.law.cornell.edu/cfr/text/14/91.217
>

I believe the typical situation is much worse than that. 91.217 only
seems to require that the equipment meet that standard on the day it was
calibrated, and then 95% probability of meeting that standard is
accepted. After that, the equipment goes out to meet the real world
and all bets are off until the next calibration!

Also, remember that a transponder only reports altitude in 100 foot
increments, so 5,125 MSL might report the same as 5,199 MSL.