Posts about: "CVR" [Posts: 42 Page: 1 of 3]¶

TCAS for the helicopter....hmmmmmm.....I am at 200 feet per the Routing Requirement.....would I suppose Airplanes might be above me even if on a conflicting flight path?

How much higher at a minimum should they be over the required flightpath for the Helicopter Low Level route (at that point I see it as being 200 feet AGL or below)

But indications seem to show the Helicopter not at the required height above ground....although that number has some doubts due to various reasons.

Do standard IAP Procedures by Airlines require use of Glide Slope information even when VFR.....which would make me ask the question what height the RJ should have been at at the point it collided with t he helicopter.

Was the RJ Crew using Glide Slope information as part of their VFR Approach procedure for the designated runway? The CVR will let us know that in time probably.

The other question is at what point would the RJ Crew have benefit of visual glide slope lighting for the RWY 33?

Any of you Airline Pilots care to address that issue and assess that for us.

Here is the Airport data for Reagan International that shows the Instrument Approaches that are available. Can one derive a reasonable height above ground for the collision point....and/or a distance from the Touchdown Point of RWY33 for comparison to what seems to be the height and distance from the TD point?

https://www.airnav.com/airport/KDCA

The world is not that black and white.
DCA, and others nornalize collision alerts in the background of a significant % of ATC transmssions.

TCAS RA heights show mandatory Day, VMC go arounds the day prior- but how close was the helicopter to the 737 not going around 2 minutes earlier the day prior, so low TCAS TA only height below 900' allows continuing?

You think the CRJ crew, below 500', rolling out of a left turn to 33 sees the helicopter to their right or even notices the TCAS TA display? Maybe it gets a glance IF the short final is wired. Problem is the Traffic aural is already expected in the airspace, same as hearing the ATC collision alarms in their transmission background.

There will be line of sight recreations in the reports. The CRJ will not have but a scant chance to have seen the PAT25, with caveats- the CVR has to be heard.

Pat25 likely had a 500 hour pic getting a checkride in the right, distant seat and the radio PM/1000 hour pilot in left seat, seeing only AAL3130 and trying to figure out how to pass behind, cognitive dissonance with what is seen..

3 seconds later, all ends.

James Reason, Diane Vaughan, NASA, et al...

I concur with this analysis


While the LC did not do anything unacceptable per se, the second affirmation of the CRJ being in sight would have been due to his concern about the proximity of the approaching aircraft. On this basis and with some benefit of hindsight, if he had been a bit more informative about the location and distance of the heli, this could have been a point of avoidance. Maybe there were some human factor priors were the heli pilots do not like what they deem as overly verbose comms or reassurance/verification calls, who knows.

Secondly, there appears to be an instrumentation issue, pilot error or both in one or both aircraft i.e. 1. no warning or awareness of warnings on a clearly impending incident - I only used TIS when I was flight training in the US some years ago, so again, some speculation. For CRJ, could be they had become accustomed to flying a few feet above helicopters there that they ignored such warnings 2. altitude deviation - could be mechanical, airmanship, wrong QNH etc.

Thirdly, the margins for error in the operating environment as many have commented appear too low, though in general there are low margins anyway when you are close to the ground.

If they [heli crew] were supposed to be following behind the CRJ, why were they getting that close to rwy 33 extended centreline or were they planning to turn once crossed? Was the CRJ centred laterally or did it perhaps slightly overshoot to the right?

I think it's more likely that the heli crew mistook the landing plane for #1 for rwy 01 rather than one taking off in my opinion, which leads me to think they may also have misidentified rwy 33 or the alignment to it at least. The latter may be an easy mistake at night. I would expect that part of the heli crew would have been very familiar with the territory, which makes it even more puzzling. The circling to land also adds a degree of ambiguity as to their understanding of the initial position notification or their expectation of where the landing a/c should be.

Anyway, we'll see when the prelim report comes out. I certainly hope there was a functioning CVR in the chopper.

Helicopter single box combing CVR+DFDR has been recovered and looked good. No exterior damage.

Aircraft CVR had already been recovered, showed water ingress, was soaked in ionised water, then into oven for getting water out, still checking connectors \x85 but high confidence to get audio out.

Aircraft FDR already recovered, no water ingress, soaked in alcohol, looked good, ref 2,000 datapoints, high confidence to get data out.

NTSB investigation runs parallel to DoD investigation (I assume that will be the usual double), but independent, so NTSB got its own heli on-type licensed pilot in the team.

Investigation has a closely matching config CRJ available to match recovery of items and seating and cockpit config with items being recovered (which are refd on grid coordinates).

Main lift starts tomorrow and may take days. Prio 1 is still recovering all the victims. After that heavy lift of the big chunks starts on Sunday. This will take days.

ATCO interview(s) has already started. The history of the wider ATC team of controllers will look back for 24-72 hrs probably. But also at level of hiring and training.

PoB manifest are, by law, never published by NTSB and are excluded from FOIA.

Just an unimportant nitpick but I can't imagine they used "ionized" water, more likely they used deionized water, which is just really pure water like distilled but even more pure.

The fact that it seems to have become acceptable to erase or overwrite or "forget" to preserve CVR following a near miss or incursion suggests problems deep within regulators and carriers. Fortunately, through completely unrelated activity, 25 hour recorders should mostly resolve this, as long as aircrews don't continue to religiously combine the parking brake and erase buttons. Unfortunately, for now, the only sure means of preserving a CVR is the expiration of the crew and/or loss of the hull.
We've been fortunate and simultaneously unfortunate that 1000+ runway incursions per year and an increasing number of near misses has resulted in zero passenger deaths until now.

Fair enough. I inferred his experience in military helos from his many discussions of his experience training flight crews. I'm not sure what other of his statements you consider "inaccurate" though, and you don't bother to back that statement up with any specifics. Would you care to expand on what inaccurate advice he gave?

What I can say about Mike is: he puts his name and his face and his reputation out there in public to have open discussions about flight safety, and in the context of this totally preventable collision, it would be beneficial to all if every expert here and elsewhere on the interwebs participated in a similarly open and public debate in relation to this incident. If you disagree with him, message him and invite a public debate.

I've lurked and read this forum for a long time. Decades? I can't even remember how long. Much as I enjoy reading it when a major incident occurs, it frustrates me to no end how it is filled with so many examples of institutional inertia, acquiescence to mind-numbingly antiquated regulations, ridiculous politics, and endless excuses, all of which inhibit the progress of technology and safety...not to segue into a rant but the most obvious example being, and which 99% of the non-flying public would agree with, that there is almost zero reason at this point to not have cameras in the cockpit and perhaps even live transmission of video and/or audio feeds on every commercial aircraft at this point \x96 the power and data/bandwidth requirements being miniscule relative to the benefits, at this point it is simply absurd that such features do not exist; the Jeju incident's loss of CVR data being the best recent example of what a hindrance to technological progress aviation regulations have become, when for a few dollars a consumer can own a tiny little dashcam that records stunning 4K video and broadcast quality audio in near total darkness with 100mph wind noise running on a small and safe lithium batteries trickle charged from a 5 watt power supply for days on end, which can be broadcast via wifi link to Starlink-satellite based internet across the entire planet. We live in the Space Age, but the data storage and recovery procedures for commercial aircraft still hearkens back to WW2...

That rant aside, as the videos posted above by others demonstrate:

- A Blackhawk can in fact stop on a dime (so whatever you're suggesting Mike Blackstone was wrong about, it certainly wasn't that).

- Obviously that shouldn't be the plan , but it still a legitimate question to ask, in the context of an emergency, and when every other safety precaution has already failed, why couldn't it be done? Other poster's rationalize: at the low altitude, there's nowhere to go. The videos demonstrate otherwise. You can stop a Blackhawk 50 feet above the ground in seconds. If deviating in any direction is a risk, why didn't ATC just say " PAT25 slow to stop and hover!" \x96 as a Very. Last. Resort?

- I don't understand how we can have a system of "Air Traffic Control" that defers its control to aircraft at night around a busy airport with intersecting approaches. It's nonsensical. I honestly didn't know it was a thing. I thought all major airports had flight paths that kept inbound and outbound aircraft in separate non-conflicting lanes at all times. Obviously, I'm extremely naive. From my perspective, it seems as though the professionals involved are allowed no intuition to deviate when the procedures clearly compromise safety? Apparently they're all reduced to being bots who can only read checklists? If that's the case, then why not run the whole system on "AI"? I know I'm being spicy by saying that, given all the pilots on this forum who harp on about how stupid AI is (true for the moment, but not for much longer, rest assured), yet many consider it perfectly reasonable for ATC procedures being to read out the type of aircraft to a pilot who is flying in total darkness in order to fulfill delegation of its responsibility to control air traffic, as if that procedure actually helps? Are we through the looking glass? It doesn't take a three year NTSB investigation to infer how stupid that is. Yet some defend it. Why?

NTSB on CVR recordings as I understand - however read from a paper:

remarkable: begin of pitch up 1 sec before impact (CRJ).

Having been in a mid-air collision with similar geometry, I would bet it was only normal input to approach path. FDR\x92s are incredibly sensitive recorders. I have a vague memory of the other plane\x92s wing flashing by. It looks slow in the videos, but it\x92s incredibly fast.

The CRJ CVR transcript does show the "Traffic! Traffic!" callout, but since this was a visual approach (non-precision in VMC even though it was at the end of an IFR flight) and visual separation was in use, why would both parties not be explicitly informed by the controller?

"5342, helo traffic on your right 1/4 mile at 300 feet, has you in sight". The CRJ FO might just have taken a closer look out the side window with that. Or, like you, they might have opted to go around.

deltafox44
Not at all. The briefing indicated there may be a possibility that the altimeter in the BlackHawk displayed an inaccurate altitude reading and that the discrepency was in the order of approx 100' given the height at which the collision is known to have occurred.
Briefing the RT comms, NTSB stated that a portion of the ATC instruction to the BlackHawk to 'pass behind the CRJ' was received in the Blackhawk (according to the CVR), truncated due to the BlackHawk keying the mic at the same time. Apparently, the words 'pass behind the' were missing from the BlackHawk CVR.

(my bold in quote) well.... that doesn't surprise me.
For a couple of days now, was thinking about posting something on an "extra noise" I keep hearing in the R/T comms, when TWR gives the ' pass behind ' instruction. Was wondering whether TWR's Tx wasn't stepped over by someone.
My first impression was that the extra noise came from an radio call from a turbine helicopter (given the typical background noise often heard in radio calls from turbine helicopters). And was wondering if it wasn't PAT25 that started replying to TWR's first ' in sight? ' call, effectively blocking part of TWR's second call, the ' pass behind ' part of the instruction.

In attached mp3 (in .zip per forum attachment requirements) around 00:05 I hear this 'extra noise'.


Edit:
well, this seems to confirm my initial impression:

I'm not sure they did say that about the altimeter, they said that there was bad pressure altitude data recorded on the FDR. That's not the same as saying the altimeter display was wrong, although it does mean that it's going to be hard to infer what was actually displayed on the Baro Alts. I would have thought a military crew would be pretty solid on altimeter cross checks though so I think that's all a bit of a red herring. The Potomac is (give or take the tide) at sea level so I think we can be pretty confident that the RadAlt figure of 278ft is good for an altitude too.

Jennifer Homendy (NTSB Chair delivering the press conference) stated that the CVR of the Blackhawk had no discussion
relating to seeing the CRJ in the last seconds before impact. The crew didn't see it coming.

They stated the crew was likely wearing NVG, this would explain that

Novice question here but would the Blackhawk usually have a CVR onboard most of the time?

CVRs are permanently installed equipment, not carried aboard. They are wired in to both record each pilot plus area microphones.

It appears from the NTSB's most recent press conference that the instruction "pass behind the CRJ" was not heard in the helo's CVR and, therefore by inference, not heard by the crew. Am I correct in assuming that there is no requirement to readback an instruction like that in the USA? ATC appeared not to expect one.

The Aeronautical Information Manual lists a number of instructions that should be read back, but there are none that must be read back (unless the controller specifically requests). "Pass behind..." is not even one of the "should" be read back instructions, so ATC wouldn't be bothered by not getting a read back. Frankly, if there was a requirement to fully read back all things like "Pass behind..." the frequency would be constantly full. In any case, whether PAT25 heard the "Pass behind" or not, it had already said that it was providing its own visual separation, so not hearing an instruction to pass behind does not take away the requirement to maintain separation.

+1 to everything you and Wide Mouth Frog said.

I sincerely hope the NTSB can avoid being distracted by the distractions of altimetry and the missing ATC words on the Blackhawk CVR.

Upthread, Luca Lion calculated the 3 degree PAPI approach path as crossing the eastern riverbank at 270ft. If that's correct, then the CRJ's 313ft radar height 2 seconds before collision puts it at least 43ft above the approach path, so the Blackhawk's radio height deviation of 78ft would have contributed only about 35ft to the erosion of any intended "procedural separation" (*) between the aircraft. Or, to put it another way, the same outcome would have resulted if the Blackhawk had been at 235ft radio and the CRJ on the glide. Height keeping of plus or minus 35ft can only be achieved by instrument flying, which is obviously not compatible with visual separation (or indeed VFR) so cannot be reasonably cited as part of a safety case for the procedure. And of course a landing aircraft could easily be below the glide. Altimetry and height keeping are not the cause of this accident.

Missing the word "circling" wouldn't have influenced the helo crew getting visual with the CRJ at the time of the trasnmission. At best, it would have given them an extra nudge that "runway 33" (which was audible) meant the CRJ would be taking an easterly flight path. Missing "pass behind" with only a few seconds to collision was irrelevant if, as seems likely, the helo crew did not see the CRJ at that point.

(*) The quotes around "procedural separation" are intended to convey a tone of disgust and sarcasm.