AA jet and Military helicopter collide over Potomac 8

Reagan National Airport crash: Military Black Hawk helicopter collides midair with American Airlines jet

An Army Black Hawk helicopter collided midair with an American Airlines flight from Wichita, Kansas, at Reagan National Airport on Wednesday.

www.foxnews.com

 

[Alistair_Heaton]

A bit of dust in my eye. The CRJ crew Ian and Danasia on arrival in CLT being taken home by AA.

Rest in peace,

 

[drwebb]

Hats on and videoing for their FB post to impress everybody they were there - people got no reverence anymore.

 

[DirteJoe]

Key notes from the NTSB briefing today.

No evidence of pilots not wearing NVG's.
8:43:49 PIC was on voice recorder calling out 300ft, but Instructor pilot said 400ft, but they did not discuss any further.
8:44:27 Instructor pilot indicated 300ft descending to 200ft.
8:45:30 Instructor flying again indicated they were at 300ft and needed to descend. PIC said they would descend.
8:46:01. ATC instructions and CRJ callout heard on ATC and CRJ CVR's, but the word "circling" was missing on the Black Hawk's CVR.
8:47:39. ATC asked the Black Hawk if they had traffic in sight with audible CA's in the background. CRJ also received TCAS alerts.
8:47:42 ATC and CRJ CVR's recorded full ATC instructions again, but Black Hawk CRJ missed did not record "pass behind the" ATC transmission was stepped on by a radio transmission from the Black Hawk cutting off the ATC.
8:47:44 Black Hawk confirmed CRJ in sight, request visual and approved.
Instructor pilot then told the PIC they thought that ATC was telling them to turn left towards the bank.
8:47.58, CRJ increased pitch to 9* nose up and elevators were deflected to maximum nose up. 313ft last recorded altitude. 9* nose up and 11* left wind down, descending at 448ft/min.
Black Hawk altitude was 278ft from 5 seconds prior to collision to the collision. 0.5* nose up and left 1.6*
Black Hawk altitude data is not being released yet for its entire route due to a lot of conflicting data.
Black Hawk PIC and Instructor had no radio altimeter readouts and relied on barometric. Pressure Altitude data is faulty, but not known if it was to the FDR only or to the flight systems as well.

It's unknown why the Black Hawk was not transmitting ADSB.

 

[Garbage1]

NTSB also stated there are no lateral boundaries associated with the helicopter routes shown on ATC helo route map. Thus 200' max helo altitude is even more problematic as helo nears runway bank of Potomac River. Designed to fail.

From an Army training perspective, it would seem PIC should have been aware of radio and barometric altimeter readings, as that is how to validate their accuracy. Radio altimeter should be the more accurate sensor, and perhaps the one the PIC should have been paying attention to at low altitudes?

 

[Alistair_Heaton]

I seem to remember there is issues with rad alt and the return off water.

 

[DirteJoe]

One of the tricky things with flying with NVG's, is you cannot look directly at your gauges. A lot will be washed out from digital displays and lights. You'll be glancing out the side at the gauges and using your peripheral which isn't something you can constantly keep doing while flying visually. I don't think they'll find the gauges were reading differently. Just that the gauges were being read differently as well as repeated altitude corrections with a constant 0.5* nose up attitude leading to drifting in altitude.

Though still, if set accurately, at least per our old MIL-STD books, 278ft of altitude on baro could read as roughly 220ft on the dial face and be within spec. +/-.06 inches of mercury is spec. Radalt over water would more likely be more accurate that night. Less ground clutter.

 

[Alistair_Heaton]

There is something "physics" involved.

Same physics as issues with the weather radar and large droplet water movement in CB cells.

 

[DirteJoe]

I could be mistaken, but at low altitudes there is not as much of an issue. You'd see radalt inaccuracies over water at higher altitudes.

 

[Alistair_Heaton]

Don't have a clue... I am commercial air transport fixed wing.

It comes on less than 2000ft but we don't use it unless doing low Viz approaches cat 2 or 3.

It is used for TWAS and a few other things but the pilots are not involved.

 

[Garbage1]

Generally Radar Altimeter should be 2-3% error range below 2500' overall.

For Radar Altimeter, a 2% error at 278' amounts to 5.5'. Whereas barometric altimeters allow up to 70' variation at any altitude, before failing allowed performance specification.

At 2500' a Radar error of 3% equals 75'.

Calm Narrow River Water not an issue for radar especially with updates say 25 times per second. Not once every 5 seconds like ATC WW2 Radar Technology.

 

[FacEngrPE]

The preliminary NTSB report is out
News Release

Reports​

• AIR-25-01

Investigations​

• DCA25MA108

This illustration clearly explains why the recommendation is to prohibit helicopter flights when the runways are in operation.

 

[LittleInch]

Pretty comprehensive report.

The number of near collisions though is really quite high and with a TA of one per month this really was a collision waiting to happen.

Only Issue I see left from a technical point is what was the reading or accuracy of the altitude that the helicopter pilots were using. The radio alt though stated 278 ft at point of collision.

From a pilot perspective there isn't anything I can see about what the pilots can see with NVG on and if they could actually spot a jet coming towards them pretty much head on. Also there's no indication of what the pilots on the jet did or said when they got a "traffic traffic" warning some 18 seconds before collision. At the same time a CA warning can be heard on the ATC tape. Missed opportunities to avoid this abound, but the automatic detection equipment seems to be have done its job, but just not followed properly

Now maybe that airport has a history of these near collisions and people just carrying on letting the controllers sort it out, but that to me sounds a bit odd.

 

[Alistair_Heaton]

I suspect there were more TCAS events but locals got bored of filing reports on them.

It's a bit like gear down EGPWs warnings on runway 14 in Zurich due to a telephone mast at 6.5 miles finals which takes the rad alt to 950ft.

 

[LittleInch]

There goes Feynmans famous "normalising failure" issue.

Now it might come out in the full report as to what was actually said inside the cockpit when the traffic warning sounded and also why the ATC didn't act on the CA warning to do something more positive than just ask the helicopter pilot if they could see "the CRJ". The lesson is that you disregard safety warnings like this at your peril. Applies ot all manner of industries, not just aviation. I saw an ACI recently on Independent air 1851 (1989!) which flew into the top of a mountain where the pilots had 8 seconds of terrain pull up warnings and did zilch, because their SIM training told them to ignore it and there was no training on how to deal with the warning.

It's just such a massive shame and personal disaster for some many people that 70 people are dead for what is clearly an avoidable collision.

 

[Garbage1]

The NTSB Report of Conflicted Air Space between helo's and air planes NTSB chart for route 4 is very kind to whomever designed this DEI (Dead End Idea) airspace operating parameters. The redlined Flight Conflict Chart below, shows a better representation of the true conflicted route 4 air space in red. The helicopter had no lateral boundaries on the route over the Potomac and no lower flight restrictions other than avoid visual conflicts.

Further it has been stated that barometric altimeters accepted tolerances can vary 75'. Thus the best case scenario showing 75' of clearance on left bank of Potomac is completely eliminated by altimeter allowed errors, depicted by dashed red tolerance range.

I am not sure where the NTSB 100' to 200' helo altitude numbers come from, since all that is on FAA Maps is Max altitude with no lower limits other than visually avoid ground conflicts and higher is better for sound abatement.

Assuming radio and barometer altimeters both are calibrated to reference the bottom of air frame, there is height of air craft from bottom reference point of altimeters to top of air craft which further reduces size of the needle. Perhaps another 15-25' tolerance stacking issue.

 

[LittleInch]

The use and route of Route 4 crossing the approach to runway 33 is plainly nuts and it seems it was simply the fact that the traffic onto runway 33 was only 5% of the landings being the only reason why this collision has not happened before now. Eventually all the holes in the Swiss cheese will align if you let it run and run.

 

[spsalso]

Since runway 33 is lightly used, there would be minimal problems if helicopters ALWAYS had to stop a fly-through when a plane was due through that area.

It seems so obvious.

I wonder if a lot of Very Important People flew on this helicopter route. That could explain why it was unacceptable to hold the helicopter until the route was properly clear.


spsalso

 

[Alistair_Heaton]

Wonder if military have a ceiling alarm for excessive height above ground.

Civi we have minimums for rad alt.

We have a target on baro altitude plus minus but no where near the resolution to do this.

The plainly nuts is a good description but also it's not unique.

 

[LittleInch]

I was wondering and not sure if anyone has an idea what sort of resolution the pilot would see on the instrument panel.

Is it a mixture of a needle and also a number? Is the sweep of the needle one per thousand foot? Does the number only change in discrete lumps?

how easy is it se in a night situation with dozens of lit instruments?

The way everyone seems to talkin hundreds of feet and not say Altitude 270ft or 220?

This is what I can find, but don't know if its the same as the one which crashed. If so it would seem to be quite clear the helicopter was a lot higher than 200 ft.

 

[Alistair_Heaton]

I don't know and have zero experience flying low level at night in a fixed wing never mind rotary.

During day time fixed wing I wouldn't be looking at the instruments at all. I would be judging height by eye.

In my world the rad alt counts down the height in 100ft incremental from 500ft.