Altimeter in Black Hawk helicopter may have malfunctioned before DCA mid-air collision
Posted by Knightbear49@reddit | aviation | View on Reddit | 204 comments
SeaConsideration722@reddit
Covid cabel is the reason for this disaster sadly. At least two of the hawk pilots were to show in court the following week but someone had plans for them. The hawk can be remote flown...there was discrepancy heard on the hawk about altitude and i believe likely it was but also regarding that they have no control over the hawk now. They had proof regarding covid's truths and it would have caused serious damage to higher officials with government agencies. Hence why her name wasn't released they had to clear any info attaining to rebecca regarding covid so that people wouldn't find or know the truth and it would all be a mistake with no one really to blame!! Theres many questions that arent being asked they are always regarding the same thing. Also no photos of any hawk crew with their families but the CRJ has them. I'm sorry to all that believe the government media shows they are paid to tell u what they want u to hear. Bless the souls lost in this coverup my heart hurts for the pain it's created to many many beautiful people, families and friends đ˘
ktyd1d@reddit
thatâs absolutely crazy, please just delete your comment
adw2003@reddit
Iâm a former navy 60 pilot. We always used the radar altimeter as our primary instrument for altitude over water. Is it not the same in a Blackhawk?
rawleftover@reddit
I also thought of this. Usually aircraft have both barometric and radar altimeters. For a aircraft like a helicopter I would imagine that a radar altimeter would be substantially more useful as you are closer to the ground and the ground-level fluctions are a bigger issue than in a plane. I seriously question if the crash can be blamed on faulty equipment as I highly suspect there were multiple altimeter devices not just gauges.
Optimuspeterson@reddit
Helo routes are MSL as most in DC are over land. Doesnât matter if your RADALT reads 110 or 280â as long as your BALT reads below 200â
Irate49@reddit
Itâs the same in a UH-60. This is not a good theory given how Army UH-60 helicopters operate.
yeahgoestheusername@reddit
I would not be surprised if this becomes a the textbook example of all the holes lining up: altimeter possible indicating wrong, traffic alert being confused for departing aircraft, keying mic just when tower was giving specific traffic alert, wearing night vision goggles which limited peripheral view (and made aircraft lights blend with ground clutter), CRJ in a low altitude left turn instead of a long stabilized final. It really feels like a getting hit by lightning odds thing because if any one of these things hadnât happened the crash would have been avoided.
headphase@reddit
DCA has been slicing and shuffling the Swiss cheese for decades, it's actually a bit surprising it took this long given the facts that are coming out. What's really alarming is that each of the stakeholders have apparently each known and normalized a specific factor that the others didn't.
ATC probably didn't realize this was a training flight with NVGs.
The Blackhawk crew seemingly didn't realize that ATC wouldn't give them more warning about a plane circling for 33.
The CRJ probably had no idea that the helicopter corridor could be within 100 feet vertically of the 33 glide path (I've operated CRJs into DCA and never knew that!)
yeahgoestheusername@reddit
Yes, I canât imagine even the most GA of airports allowing aircraft to cross final with 100 separation. Especially if the aircraft wasnât flying a precision approach. Tower was clearly way too comfortable, meaning theyâd made a regular habit of it, as youâve said, of threading that kind of needle.
storbio@reddit
Yeah, it's clear this kind of behavior was so normalized that ATC treated it like just another day.
The politicians and administrators who created this environment need a serious dress down. They put convenience at the expense of safety and this is on them.
Fly4Vino@reddit
I think these routes are also flown to evacuate officials in an emergency so that night proficiency with the airport active is needed.
headphase@reddit
If there were a true emergency in DC, I would put money on an instant ground stop and diversions for all of DCA's traffic- the helicopters would be the only things flying.
Fly4Vino@reddit
That's potentially true but the helos need to practice the routes . I assume departures of important folks would continue but inbound would not in the event of an impending emergency .
I think the most glaring issue was the issuance of a circle to land Rwy 33 with a helo running the river and perhaps controller overload. I listened to the last 20 min of the tape. 200 feet of vertical separation and the helo operating on a very narrow fixed route was simply an invitation to disaster.
I believe the process originated with a slow departure of a preceding flight which initiated the change in runways for the inbound commercial jet or in the alternative , direction to initiate missed approach procedure (assuming that this did not conflict the departing traffic)
Fly4Vino@reddit
I believe it was a checkride. Question if this was a rush to meet an impending deadline for completing the checkride . She had been very active at the White House were she worked as an aide to the former President . She was Soros' escort when he came to receive his Presidential Medal.
Primary_Appointment3@reddit
She was Ralph Laurenâs military escort.
L337Sp34k@reddit
that seems like an unnecessarily slim margin for error, right?
TommiHPunkt@reddit
tons of reported incidents caused by this crazy route planning in the past, even the day before the crash. Probably way more unreported incidents. Complete negligenceÂ
rckid13@reddit
Unfortunately most airline crashes are examples of all the holes lining up. The last three US airline crashes: Colgan 3407, Comair 5191 and American 587 were all a series of super unfortunate things that lined up at the wrong time. In both American 587 and Colgan 3407 the crews had recent training on obscure things which made them believe those things may have been happening. Reacting the way they did is what made the situations worse.
yeahgoestheusername@reddit
True. But those seem to be one big thing (say ice build up) that aligns with a few other things (fatigue, inexperience, training) rather than nearly ten small details that all aligned. Not that there isnât one, but I canât think of an accident where there were so many holes that had to align. Iâd hope this signifies something: That the simpler alignments arenât happening anymore and it takes these freakish alignments to cause accidents.
CPTMotrin@reddit
Bad data or not, they shouldnât have been crossing the approach to rwy 33 with an aircraft on short final.
epsilona01@reddit
They were following a route designed to practice the emergency evacuation of government officials in a crisis under the Continuity of Government Plan.
The UH-60 was outfitted for executive transport, their call sign PAT25 meant "Priority Air Transport 25" and they were engaged in routine retraining along a corridor that elements of the government would use to evacuate. They had good reason for being where they were, doing what they were doing.
Fly4Vino@reddit
The swiss cheese started lining up the holes when the ac departing got off to a slow start and they needed the CJ to circle to 01
epsilona01@reddit
It was interesting to read they may not have heard the 'go behind' instruction, which did seem a little late in the sequence of events when I first heard it. We'll find out in a year or so either way.
Fly4Vino@reddit
I think the most critical was that they appear to have missed the change from RW 01 to circle to land RW 33 . The were probably expecting the turn in for 01 way out in front of them.
They are flying a checkride under NVG down the river with very tight lateral and altitude limits. Pure speculation on my part but I would imagine that there would be a prohibition for issuance of the circle to land RW 33 with a helo running the river .
I listened to the controller audio for about 15 min prior and there was a lot of traffic as he was handling both the approaches and releases. It sounded like the change in runways for the jet was due to a slow departure by an aircraft released from a conflicting runway.
epsilona01@reddit
Would it have made a difference that the PAT25 was operating on a different radio frequency to other traffic?
CPTMotrin@reddit
Perhaps they should have trained at 2am when there is very little traffic. Perhaps they should have turned on their ADS-B transponder which could have triggered the TCAS system of the CRJ. Most accidents are a cluster of small mistakes that add up to a tragedy. As a private pilot, I cannot understand why this âpractice current proficiency flight â required contaminating an active runway approach.
epsilona01@reddit
Because the point of the exercise, which is a regular one and until this incident has been flown for decades with no harm at all, is to fly in realistic conditions.
Not for nothing, but in that airspace you have an international airport, and 5 or 6 military bases all producing traffic.
Military aircraft fly with ADS-B off. ATC had collision alarms.
Because when flown for real it would be, and those flying it need to practice operating in those conditions. That's the whole point.
CPTMotrin@reddit
I get the point of practicing. But Iâm not fond of 67 deaths âbecause we were practicing in real world environment â. The first rule of flying is âdo it safe!â Just because it worked many times before, doesnât make it safe. If changes are not made, why would any sane passenger, pilot, airline, or insurance carrier ever fly into DCA with this now know risk?
epsilona01@reddit
This is a really disingenuous assessment. A group of talented pilots with thousands of hours of flying experience do not accidentally fly into a commercial jet without something going seriously wrong (as NTSB says).
Because it's safe airspace. Two major accidents since 1982.
SyrusDrake@reddit
They shouldnât have been crossing the approach to rwy 33 at all, period.
I don't know if that's a Washington specific thing, but the routing of those helicopter tracks sketches me the fuck out.
heliccoppterr@reddit
Great observation captain obvious
Username43201653@reddit
Not obvious to the NTSB as they're jammerjng on about altimeters. The RJ was for all intents on glideslope. Is ATC relying on a 175' difference for separation between the route and glideslope. That's the elephant in the room - dumbass authorizations and procedures. Should be, if a plane is circling for 33, no military traffic you can't use Route 4. Simple, right? It was an accident waiting to happen.
biggsteve81@reddit
I'm sure it is obvious to the NTSB. But in the initial phases of an investigation they are only publicly announcing facts, not causes and blame. That will all come in the final report, as they want to make sure they cover all the causes of the accident.
conaan@reddit
ATC does not rely on just vertical separation, the call for visual separation is standard to provide ample horizontal separation as well.
Username43201653@reddit
True dat. Traffic keeps separation in a pattern. The fatal flaw is you're relying on another human to do the job. But that's also how you prevent gridlock.
conaan@reddit
You are right, it's a fatal flaw and I can't dispute that. At some point in and system there has to be some trust for people to do their job and not cause an incident. Nothing truly stops me from driving down the interstate backwards, but plenty of infrastructure is built to dissuade me.
As it comes to flying in that area, calls for traffic and visual separation are constant, even if you are just crossing the tidal basin they will call out the aircraft descending on final near cabin John (far up the Potomac, near the 495 bridge) and require you to have them in sight before you cross memorial bridge. The most difficult traffic avoidance in that area is honestly other helicopters, as it can be very hard to pick out a helicopter from the ground clutter if you are, for instance, plopping along zone 2 with traffic coming up route 1 around RFK to the same zone
Username43201653@reddit
All the layers lined up on this one. Timing, ATC busy, checkride, NVGs (maybe), multiple aircraft to see, route overlap/design, complacency to dangers, like you said ground clutter. The tight rope wire snapped.
FencingNerd@reddit
Too much helo traffic. Sure, that's great, can't use route 4, but there's a ton of mil traffic on route 4. So basically what you're saying is either close R33 or route 4. Guess what, no one wants to do that.
RedSquirrel17@reddit
This has been butchered by the mainstream press unfortunately.
The NTSB said that the Black Hawk's final radio altitude was 278ft AGL. This data has been fully validated. The barometric altitude displayed to the pilots on their barometric altimeters is not recorded on the FDR, nor is the pressure calibration setting inputted by the pilots. Further investigation is necessary to determine this information.
However, the FDR records the aircraft's pressure altitude, which is the altitude calibrated to standard atmospheric pressure â 29.92 Hg. The NTSB determined that this data was invalid. The cause of this, and what effect this may have had on what the pilots were seeing on their flight instruments, has yet to be determined.
Ziegler517@reddit
Wasnât it also stated that they knew they were above the 200ft maximum and that the PF (pilot flying) acknowledged this from the PM (pilot monitoring), and stated they were descending. Would love to see the data lined up to comms to see if they did and what the deltas were. Iâve never flown at night under NVG at 200-300 ft, so I donât know if a 25ft delta looks and feels like 100ft in those conditions.
logginginagain@reddit
I have and it is obvious to an experienced helicopter pilot. 300AGLis a full 50% higher than 200AGL. Parallax, horizon, speed cues, size of objects, and other cues are all noticeable.
whsftbldad@reddit
I seriously do not know so I want to ask if the cues are still noticeable if they were actually wearing their goggles?
logginginagain@reddit
Yes for a pilot with good situational awareness. Better than unaided.
i_should_go_to_sleep@reddit
Itâs harder to pickup on the cues and relies on a heavier instrument crosscheck. If someone hasnât flown goggles in a while, they can tend to be higher because the cues arenât as accurate, but hard to say if that played any part here.
whsftbldad@reddit
Thank you for the response.
rckid13@reddit
Ultimately their ~100ft altitude discrepancy is going to be one small piece of the puzzle, but it won't be anywhere close to one of the major causes of the crash. The media is running away with the altitude thing because the NTSB found some strange discrepancies. But ATC would never separate planes by 100 feet. Had their altimeters been perfect this still would be a very very serious event.
The blocked radio transmissions, and the limited visibility with night vision goggles I think are much bigger deals, but the media has had less coverage about those two things. Those will become major factors in the cause.
donna_donnaj@reddit
Missing a transmission should not be a problem. The helicopter should have read back the instructions, and ATC should have noticed that they were not read back, and repeated them. Am I missing something?
Remarkable_Essay_427@reddit
I agree... They had requested visual separation which ATC had approved. Regardless of whether they heard pass behind the jet or not, it was the pilots responsibility to avoid that aircraft. This may be one hole in the cheese potentially but not a big one.
haarschmuck@reddit
Think a lot of the issue is that itâs military. The FAA would never allow civilian traffic to have a setup like this but since the military needs it they seem to oblige.
The fact that there was a near miss the day before is wild. In that case it seems the pilots executed an RA but they are inhibited under 1k feet.
Fly4Vino@reddit
It sounds like they may have missed the runway change for the jet. For RW 01. the altitude would not have been so critical. RW 33 put the inbound jet much lower over the helo route.
i_should_go_to_sleep@reddit
Civilian helicopters fly that route too. Itâs not just military. I have been on that route with medevac, police, CBP, etc.
Superbead@reddit
Not just one near miss the day before, but two and possibly three depending on how you count it
TinyBrainsDontHurt@reddit
Thankyou, I was looking for this, there is no way that a \~100 feet clearance would ever be allowed. The problem was not the altitude.
FormulaKibbles@reddit
Well that's the thing. ATC would separate them by around 100 feet because that is what they've been doing for a while. The helos are supposed to be flying 200 feet AGL or less. As someone who has flown into DCA numerous times, helos are always flying that path we've seen in that crash but are staying in their (small) lane.
RedSquirrel17@reddit
There was a discrepancy between what the two pilots were verbally indicating to each other.
Ziegler517@reddit
As someone that may know far more than I, could they potentially see what the altimeter was dialed to in the wreckage? Or will it be to mangled to determine?
Hiddencamper@reddit
Either wayâŚ. Iâm of the opinion that the altitude limit does not provide adequate protection for landing or departing aircraft directly off final/departure. It likely only provides protection for the departure and arrival routes. But not final/departure.
So everyone wanting to go after the altimeter, itâs also possible for the landing aircraft to be low and be completely legal. The only adequate separation is visual or lateral.
Fly4Vino@reddit
The tiny vertical separation provided for an aircraft inbound for 33 seems crazy to have a helo following the river
Question - It appeared that she was flying less than 100 hours per year , is that normal for that airframe?
Hiddencamper@reddit
It doesnât provide vertical separation. The ATC minimum for vertical separation is 500â unless the pilot confirms visual separation.
My opinion, is that this route never allows uncleared travel across the active departure or arrival end of a runway. And in order to clear, ATC has to ensure separation.
The elevation limit of 200â is for situations where ATC is not directly involved. For example, a plane has an issue during the landing and has to go around (the Minimum descent altitude for most approaches is 200â) or a diverse departure procedure. Situations where a plane may need to take some immediate action and you need to provide limited protection to an area because you donât know if that plane may end up off course due to a navigation issue.
But under no circumstances does 200â provide adequate separation.
DeltaV-Mzero@reddit
Itâs wild to me this traffic pattern was a normal thing
UH60Mgamecock@reddit
Digital altimeter on an MFD. it should have been recorded on the Voice Audio Data Recorder
jit702@reddit
It was a Lima
UH60Mgamecock@reddit
My mistake. I just assumed VH-60s were Mikes.
myaccountsaccount12@reddit
It wasnât a VH-60. That was incorrect information, probably coming from the fact that the same unit does fly the VH-60 gold tops.
The aircraft involved was a UH-60L according to Wikipedia.
Feeling-Tutor-6480@reddit
If it is a glass cockpit probably not
i_should_go_to_sleep@reddit
I have no inside information, but to me, this looks like possibly one pilot looking at the radar altimeter and one pilot looking at the MSL. The correct altitude to follow in the routes and zones is the MSL, but I had many new copilots resort to flying radalt 200â when I was flying there.
DouchecraftCarrier@reddit
I'm but a mere enthusiast so forgive me for asking - wouldn't radar altitude be more accurate for this kind of environment? Or is the idea behind using the altimeter that they're in a controlled environment in radio contact with others so they need to make sure they're using the same numbers as anyone around them?
GhettoDuk@reddit
IANAP, but I think that the procedure altitudes are based on barometric altitude, not radar. Consistently is more important than absolute accuracy, and not everybody has a radar altimeter.
adzy2k6@reddit
As stated above, radio altimiters actually give a height reading rather than an altitude. A barometer will give you the altitude defined as distance above sea level (assuming calibrated as such. When landing some pilots will set them to give a reading of distance above the aerodrome instead). A radio altimiters give height, which is the distance to the ground below the aircraft. Obviously, if you are flying over a hill or high terrain these two values are very different.
GhettoDuk@reddit
OK. What does that have to do with what I said?
adzy2k6@reddit
You can't use the radar altimiter for procedure altitudes because it doesn't actually give an altitude. It is basically there for landing when you want to know how far above the runway you are in low visibility.
GhettoDuk@reddit
That's what I said.
SuspiciousCucumber20@reddit
Not a helo guy, but I was an f-16 Avionics guy.
In an F-16 there is a switch that the pilot can use to toggle the HUD display back and forth between the barometer and the radar altimeter. And while both systems are used by the pilot of take in information, the avionics uses each of them differently in terms of which other systems take input from them.
If there is a problem with the barometer, the aircraft is "red X'd", meaning, it's not suitable for flight. If the barometer is operation but the RALT is not, the pilot can still take the aircraft.
The major difference is that once calibrated by the pilot of the ground before takeoff, the barometer is going to give a consistent height measurement regardless of whether its was properly dialed in at ground level or not. The RALT relies on the receiving antenna being able to detect the signal it transmitted as it's bounced back to it. Meaning, if you're turning or you're upside down, you're RALT will not give you an accurate distance that the aircraft is above the ground.
The Flight Control System on an F-16 gathers it's altitude data from the barometer, not the RALT.
i_should_go_to_sleep@reddit
H-60 doesnât have a HUD. And their instruments show both radalt and baro on the same screen, no need to select either or.
BosoxH60@reddit
First, under NVG there is a HUD that attaches to the end of the tube. Every unit has these and I donât know anyone who doesnât use it under goggles.
Secondly, thereâs a âDay HUDâ available that clips into the NVG mount on the helmet, so you can use it during the day. I donât know of any particular unit that has those, but we borrowed them from somewhere and used them for a bit many years ago.
SuspiciousCucumber20@reddit
I'm pretty sure the UH-60L like the model being flown during the crash has a helmet HUD.
RubberChickenFarm@reddit
Radar altimeters can be a little jumpy when flying over terrain that isn't flat sine the radio waves are bouncing off objects and the terrain. Think about buildings, hills, etc.
i_should_go_to_sleep@reddit
Radar altimeters can be pretty unreliable over water too.
Gaping_Maw@reddit
Thats surpising given how dense water is, even with a big swell it would only vary by metres.
i_should_go_to_sleep@reddit
Radar relies on reflections, moving water with waves and a little turbulence changes reflections and causes fluctuations and misreadings. Same for flying over forests where the radar sometimes bounces off the leaves and sometimes goes between the branches and hits the ground.
ExpatKev@reddit
Appreciate your insight. That being said if two highly trained military pilots and their equipment can't determine their altitude to within a couple hundred feet, that route should probably no longer exist as intersects civilian traffic in one of the busiest airports in the world.
Gaping_Maw@reddit
Interesting cheers
haarschmuck@reddit
The Potomac river is quite shallow compared to most rivers and radio waves can penetrate shallow water quite well. Deepest part of the river is 24ft.
Gaping_Maw@reddit
I guess I just assumed you couldn't find a sub with radar (hence towed rigs) so it didn't penetrative. Guess its just limited
Perpetual_bored@reddit
You can definitely detect a submarine through aircraft radar, itâs just not as reliable for a direct position because youâre relying on a radar return through two different mediums, both ways, which increases all of the variances associated with radar use.
Source: my ass. But Iâve worked with both aircraft and radar
hughk@reddit
This was mostly the Potomac and bridges though. No other structures or terrain
adzy2k6@reddit
Radio altimeter will give height rather than altitude. Altitude is defined as the height above sea level, while height is the distance above the ground. The two values can be very different.
i_should_go_to_sleep@reddit
Yeah the ceiling is for deconfliction and maintaining vertical separation from other aircraft. For that to be effective, everyone needs the same frame of reference (MSL). In DC, theyâre usually close, but slightly off, which can make a big difference.
haarschmuck@reddit
The average DC elevation is 150ft above sea level with the highest point being 410ft.
Curious about this as well.
i_should_go_to_sleep@reddit
The 200â MSL ceiling is only over the Potomac, which is right around sea level, maybe 10â sometimes, and can fluctuate based on reported altimeter setting.
Gardimus@reddit
One of them might not have had the right setting on the altimeter. It can be hard to set on NVGs. They should both have radalts though.
theyoyomaster@reddit
Iâve flown at 500 feet under nvgs, albeit a lot faster at 300 kts. Without keeping the radar altimeter in your cross check 50-100 feet isnât very discernible. Unless youâre really paying attention to references.Â
Insaneclown271@reddit
You can clearly see the helicopter was climbing all the way to impact on some of the videos.
ballimi@reddit
Doesn't matter to all the people who are suddenly aviation experts, ready with their pitchforks
No_Relative_6734@reddit
Uh, either way the Blackhawk was the wrong altitude and failed to fly behind the CRJ as instructed.
So, it's not really a mystery
Intrepid_Elk637@reddit
Doesn't really explain how they ended up in that position though.
So, that's still a bit of a mystery.
Un0rigi0na1@reddit
This all could have been prevented with an ATC callout to vector them away from approach traffic. With conflict alert flashing, I wouldn't just trust pilots who are already at the wrong corridor altitude to determine the specific aircraft in busy airspace.
Thequiet01@reddit
You mean something different they also would not have heard because apparently they were trying to transmit when the ATC gave the âpass behindâ instruction?
mduell@reddit
It would probably occupy more air time, so they'd hear part of it.
Thequiet01@reddit
I do not think that would have clarified anything useful in the time available.
CollegeStation17155@reddit
Another point from this afternoon's briefing was that the CVR on the Blackhawk indicated that they did not receive the instruction to fly behind the CRJ as their transmit mike was keyed when the instruction came in.
cowtipper256@reddit
Something to note is that radar altimeter will change with angle of bank and could change with pitch. The method of measurement is a straight line perpendicular from the plane of the antenna. As a result, if the aircraft was in a turn or a last second banking, such as before a crash, that line will project diagonally from the aircraft, creating a longer line and a higher reading. In this case, if they were actually at 200 feet above the ground, then it would be a 45deg angle of bank roughly. Ultimately, the NTSB will be able to determine if this was the case or not by using the attitude data from the recorder.
frinet@reddit
You sure about that? Iâm fairly certain my RADALT compensates for bank⌠seems like a fairly easy engineering solution too.
cowtipper256@reddit
I have flown several helicopters that do not automatically compensate radalt for angle of bank. That said, I deleted my comment because the NTSB update stated that the 278ft radalt was steady 5 seconds prior with only 1deg left angle of bank. So my comment didnât apply in this situation.
frinet@reddit
Hereâs an excerpt from Wikipedia - interestingly the radalt works regardless of bank up to about 40 degrees of bank simply due to the nature of the main lobe rather than any compensation: â Radar altimeter antennas have a fairly large main lobe of about 80° so that at bank angles up to about 40°, the radar detects the range from the aircraft to the ground (specifically to the nearest large reflecting object). This is because range is calculated based on the first signal return from each sampling period. It does not detect slant range until beyond about 40° of bank or pitch. This is not an issue for landing as pitch and roll do not normally exceed 20°.â https://en.m.wikipedia.org/wiki/Radar_altimeter
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conaan@reddit
Barometric altitude is just pressure attitude modified by the altimeter setting that tower gives the crew. FDR inputs are the same inputs that are used to generate the altitude display on the glass.
RedSquirrel17@reddit
Yes, but the altimeter setting inputted by the pilots is not recorded by the FDR, so the NTSB cannot determine what was actually being displayed to the crew on the glass from the FDR data alone. For example, if the PF inputted the wrong setting on her side, this would not affect the FDR data.
You're right though that both the pressure altitude recorded by the FDR and the barometric altitude displayed to the crew are reliant on data supplied by the pitot static system. It is possible that the bad data recorded on the FDR was due to a malfunctioning pitot tube, which would obviously be highly relevant to the investigation as that would have affected the pilots' altimeters. But this is all still to be determined.
bossness125@reddit
I am not familiar with Black Hawks but, in my experience a malfunctioning static system on one port cause a miscompare between channel A & B of the ADAHRS. This would throw a CAS message and both channelsâ inputs could be viewed in the FDR log. Is this not the case with the UH-60?
conaan@reddit
You are correct, just wanted to provide some amplifying information. Air data systems are not exactly intuitive to the average reader
mduell@reddit
METAR at the time had the baro at 29.90, so the pressure alt if recoverable will be very close.
PDXGuy33333@reddit
Whatever else, it is time for the NTSB to recommend in the strongest terms that helicopter traffic in that area be curtailed. The VIP's can walk to their flights for all I care. Their convenience is no cause for routinely endangering public safety.
Fly4Vino@reddit
A better solution is to not change runways with a helo following the river.
It sounded like there was a departure that was slow to get rolling so they changed runways for the CRJ (which the helo did not hear), they were still believing that the CRJ was going to turn for RW 01 rather than continue heading for them.
PDXGuy33333@reddit
I read the other day that there have been more than 100 conflicts with helicopters at DCA in the last 10 years. There should be no opportunity for that to happen.
\https://www.washingtonpost.com/business/2025/02/13/dca-airport-crash-warnings-helicopters-airliner/
star744jets@reddit
Did the pilots do a pre-takeoff altimeter check ? Did they compare altimeters between each other as well as altimeters with airport elevation ? Did they both have the correct QNH setting ? Any screw up in the above can become critical whilst airborne.
Fly4Vino@reddit
I think folks are putting way to much emphasis on the altitude and not on the flight path.
Airspeed12@reddit
The altimeter reading is irrelevant when they were âmaintaining visual separationâ. Sure they should have been at or below 200â but even if that altitude put them on collision course they were responsible for visual separation. They are making way to big of an issue of a factor that shouldnât have mattered. They were supposed to be flying with their eyes at that point, not instruments.
Fly4Vino@reddit
Speculation but it appears that they did not hear the circle to land change for the CRJ and likely assumed that it would turn and cross well in front of them.
Recall that they are constrained to a very narrow corridor
headphase@reddit
Nothing is irrelevant. You imply that they failed to maintain visual separation, but the elephant in the room is that everything indicates that they were looking at traffic approaching 1, and not 33, because ATC's circling callout never reached their headsets. It seems they didn't even realize the CRJ was there.
smartypants2021@reddit
The BH instructor pilot was also keying the mike and missed critical ATC instructions and never asked to repeat them. Important instructions like 'circling to land on 33' and 'pass behind the' (CRJ) were never heard.Â
Fly4Vino@reddit
Bingo - I think missing the runway change for the CRJ set them up for this. If the BH is confined to follow the river at 200 it would seem that horizontal separation would be mandatory
Jillybeans11@reddit
This I think is one of the biggest takeaways for me. I was always confused as to how they could have mistaken another aircraft with the instructions given. They didnât attempt to pass behind any aircraft, so it makes sense that they didnât hear it.
PDXGuy33333@reddit
Whatever else, it is time for the NTSB to recommend in the strongest terms that helicopter traffic in that area be curtailed. The VIP's can walk to their flights for all I care. Their convenience is no cause for routinely endangering public safety. Frankly, with the White House just 2.5 miles nearly straight off the end of runway 33 it's well past time to close this airport entirely, lest we have "an incident."
bookTokker69@reddit
The VIP pylotes can do short field take-offs. That or VTOL like the F35.
PDXGuy33333@reddit
Still, it's hard to see any good reason why military helicopter traffic should be flitting about in very busy Class B airspace used by civilian airlines.
bookTokker69@reddit
Yes, they need to be banned. Most of their jobs can be replaced by drones.
Vee-One-Rotate@reddit
MalfunctionedâŚ.or set to the wrong baro?
Different-Bottle-848@reddit
Wrong baro
InsideInsidious@reddit
Even if the helicopter had been 100 feet lower, would the wake off the plane passing overhead have knocked it around? These clearances seem insane
drifters74@reddit
I'm no aviation expert, but possibly
1ns4n3_178@reddit
Either way⌠100ft or 200ft altitude difference should not make the difference between 2 aircraft flying into each other⌠the routing is just nuts. Allowing vfr traffic to separate itself from other traffic during night while one of the aircraft is on final approach is a risky game either way.
magnumcaper88@reddit
If their responder was turned on.........
Waste_Curve994@reddit
Explain to me how this is DEI.
StoneheartedLady@reddit
I mean, they literally say that the altimeter was disabled
pierdola91@reddit
First off, how dare you assume the altimeter was white, ok?
They couldâve installed a black altimeter or an epileptic oneâwe just donât know yet.
Until then? Blame it on any of your preferred marginalized communities. God knows they deserve it.
/s
Goragnak@reddit
Obviously because our president is a dufus and it was a "black" hawk...
silassilage@reddit
No doubt they will try to find a way, rather than backtracking or doubling down on crazy ideas
elneutrino@reddit
ADSB should be mandatory
blank_user_name_here@reddit
Pretty sure they have it, not every airport uses it or has it however.
It's also not the fastest system ever.......like think once every 10-60 seconds depending on the ground system.
Thengine@reddit
Military is special. They can kill airliners without recourse.
LinderstockBeckledew@reddit
Question: how can they wear night vision goggles at an airport? Wouldn't the bright lights from landing strips and approaching aircraft result in washout?
ChiefKC20@reddit
They were an IFR flight so their heads were in the cockpit and not actively looking out. The pilot non flying should have been actively scanning but so far it sounds like they were focused inside due to the qualification flight. With NVGs on, picking up traffic would have been difficult due to the bright lights.
poisonandtheremedy@reddit
Their heads were "in the cockpit" on clear VFR night while flying thru an ultra busy, low altitude, well-lit, downtown flight corridor while wearing NVGs? A VFR corridor no less
https://aeronav.faa.gov/visual/09-05-2024/PDFs/Balt-Wash_Heli.pdf
You can't fly that route IFR.
haarschmuck@reddit
Right, but that doesnât mean we should just be fine with nighttime VFR in such a congested area.
hughk@reddit
They wouldn't have seen colour. Plane lights are coloured so you can see if they are coming or going. NVG reduce everything to monochrome. Not a problem unless you are in a crowded airspace.
Snuhmeh@reddit
There is absolutely no way they were flying "IFR."
dat_empennage@reddit
FAR 91.113(b) applies whether youâre VFR or IFR, and regardless of branch, the MIL helo was bound to Part 91 regs when operating in civilian airspace within the US. Pilots are always responsible for looking out for other traffic and giving way as required by the regs (see 91.113(g) in this case)
frinet@reddit
IFR or not you need a composite crosscheck when you are VMC.
Jturn314@reddit
Because thatâs policy to always have them on.
I used to be a crew chief on Blackhawks in the army, and yeah, it SUCKED coming into an airport with goggles on. Itâs so easy to get washed out, or easy to confuse ground lights with other aircraft, or any number of bad situations.
I definitely never flipped my goggles up at an airport so I could see.. Nope. Never did that. Never everâŚ.
AutomaticVacation242@reddit
"However, Homendy says it's unclear whether the altimeters in the helicopter were showing the pilots the proper altitude above the ground."
Huh? Altitude above the ground is irrelevant since altimeters measure altitude above sea level. I hope this wasn't the real quote by the NTSB.
LawManActual@reddit
Unless they were referencing the radar altimeter
TweakJK@reddit
Often, radalt is unreliable over water, especially if it's choppy.
hughk@reddit
This is a river, not even a lake. The wind wasn't high so it wasn't that choppy.
LawManActual@reddit
They can be
RedSquirrel17@reddit
Homendy was referring to the pressure altitude recorded by the FDR, ie the altitude calibrated to standard atmospheric pressure (29.92Hg). See here.
Goodperson5656@reddit
Wouldnât they be using local altimeter setting?
RedSquirrel17@reddit
Yes, but the FDR does not record this.
LawManActual@reddit
Noted. Thanks.
AutomaticVacation242@reddit
Could be. But that makes them even more at fault since ATC assigns altitude based on the baro altimeter.
LawManActual@reddit
It makes perfect sense they might be referring to the RADALT.
Altitude restrictions, unless otherwise stated might be in MSL, no reason to assume the helo crew wasnât referring to the RADALT.
That statement references multiple altimeters, some of which are undeniably the RADALT(s).
The statement also mentions conflicting data in the altitude, which doesnât preclude that including the RADALT at all.
I read this and think they are almost certainly referring to a RADALT.
And I read elsewhere the baro alts arenât recorded in the recorder.
AutomaticVacation242@reddit
They're using radalt when all of the civilian traffic in the area is on baro. Hence the collision.
LawManActual@reddit
Thatâs not necessarily true at all
AutomaticVacation242@reddit
We'll sure it is. It's exactly why ATC and METARs provide an altimeter setting, so all traffic is referencing the same datum.
LawManActual@reddit
Itâs quite literally not true. I reference the RADALT every single flight in this altitude range.
Why?
Because I donât really care what my MSL altitude is when the threat is the ground or obstacles around me.
We use multiple sources of information for multiple reasons.
AutomaticVacation242@reddit
We'll helicopter hit an obstacle in this case.
When I'm flying around in my Piper and another aircraft says they're at x altitude I need to know we're using the same instrument with the same settings. If he's looking at his GPS altitude or his altitude from the center of the earth that does me no good.
LawManActual@reddit
All of aviation isnât as simple as flying small GA.
For example, when youâre flying low level, especially in complex airspace, in a congested area, at night, one of the ways you mitigate threats is using a RADALT.
Your example is something completely different. And when they reference altitude externally, theyâll reference a baro altitude.
Another example, when Iâm up at altitude I care about my ground speed, I make calculations and deviations based on that. I still report my airspeed. You should be familiar with this.
AutomaticVacation242@reddit
"Referencing altitude externally" is the entire purpose of this conversation since they hit another aircraft. We're talking traffic avoidance here. If they're flying around using radio altimeter only then they're definitely at fault. That must have been the case since the NTSB is directing attention to the radio altimeter.
LawManActual@reddit
The NTSB also said the two baro altimeters seem to have reporting different values.
We donât know what they were doing, the investigation isnât done. It seems like you think Iâm saying something Iâm not. You seem to have some misplaced frustration
I have never said they were referencing the RADALT only because I canât know thatâs what they were doing.
AutomaticVacation242@reddit
You're just posting random thoughts. And that's okay.
LawManActual@reddit
Iâm posting factual information as an aviation professional with quite a bit of knowledge on these systems into this forum to help the layman understand the complex issues at play here.
That has pretty clearly somehow offended you for some reason. Itâs pretty clear to me you might have overestimated your knowledge in this particular area.
AutomaticVacation242@reddit
You're an aviation professional. Well done. I'm proud of you.Â
I fly an old Arrow but I have to pay for it myself. Come down to Texas sometime. I'll show you how to not hit other aircraft. Maybe do some forward or side slips. Do a few soft field operations on a 1800' x 40' runway when it's 100 degrees out. It's a blast.
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i_should_go_to_sleep@reddit
If they were flying 200â radalt ceiling then they were wrong. It is clearly marked as a 200â MSL ceiling. I am not saying they were flying radalt, but if they were, thatâs a foul.
LawManActual@reddit
Absolutely correct. Thatâs not howâd youâd use it. Youâd fly so you were maintaining letâs say 150â on the RADALT most of the time, and verify that you are complying with the altitude restriction.
The RADALT would have a warning set, for example 15% below your planned, to alert when an obstacle was getting dangerously close.
Low level flying presents a lot of threats (clearly) but the biggest one is the ground and obstacles around you, a RADALT is but one way to mitigate those threats
conaan@reddit
You don't fly off radar altimeter in the city, you fly the route's posted altitude or just under it. Routes are posted to present plenty of clearance from obstacles if flying in that manner, and besides a few towers around route 3, rising terrain going route to zone 3, and various construction cranes there's not much that'll be a concern
LawManActual@reddit
Oh, I see now what your problem is now @AutomaticVacation242
You seem to think used âtheyâ to refer to the pilots.
No, no.
âUnless [the NTSB] were referencing the radar altimeterâ as in, the NTSB may have been referring to the radar altimeter.
AutomaticVacation242@reddit
The chart lists a 200' max MSL altitude. Radar altimeter should have been referenced.
biggsteve81@reddit
I think the biggest problem she is referring to is that they aren't sure what the barometric altimeters were showing at all to the pilots. Especially since the PF and PM verbally reported two different altitudes.
Jayhawker32@reddit
Radar altimeter tells you how high above the ground you are
rofl_pilot@reddit
True, although in this particular case the baro altimeter reading should more or less be equal to the rad alt. The airport elevation is 14â so over the river it would basically be sea level.
i_should_go_to_sleep@reddit
Radalt over water can be squirrelly, never safe to use that in downtown DC and baro is your only true ceiling. Lots of times we were flying well below 200â radalt to maintain less than 200â baro.
railker@reddit
I'm inclined to say the phrasing of "proper altitude above ground" is an unintended mis-step of phraseology and not meant to be taken literally, as the radalt data providing their altitude above ground is the one piece of information they DO have and can say is accurate, hence their confirmation the helicopter was at 278' RADALT / above the ground, with no relevance to what their altimeters were displaying as none of that information is recorded on the FDRs.
Irate49@reddit
Iâm not sure this theory is relevant. The pilots would also be able to reference their radar altimeter and that would be a much more valuable tool at their low altitude.
mtksurfer@reddit
âALLEGEDLYâ
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Funkytadualexhaust@reddit
Radar or baro?Â
railker@reddit
They noted in the briefing that neither the barometric altitude or the barometric pressure setting were recorded by the FDR. Only the radalt, so that's the only data they have to go off of, apart from the verbal conversations on the CVR regarding the altitude differences the two pilots were seeing.
They also noted that the pressure altitude recorded in the FDR is "bad data", and so they cannot use it to determine the altitude of the helicopter during the event. To quote, "We are working to determine if this bad data for pressure altitude only affected the FDR, or if it was more pervasive throughout the helicopter's other systems." They then note the need for investigation and inspection of the pitot-static systems and altimeters to try and determine what altitudes were being displayed to the pilots.
julias-winston@reddit
That's interesting. Something was fucked, and the pilots were aware of that before the collision.
I heard about the accident, of course, but I haven't been following the story closely since then.
railker@reddit
That statement's a bit ambiguous reading it back again, to clarify, that should read "the lack of conversation." In that:
After which there was a couple of other mentions of altitudes, but nothing regarding the apparent difference in altimeters at that time, just over 4 minutes before the crash.
TweakJK@reddit
I was an H60 avionics guy way back in the day. RADALT is notoriously unreliable over water. I suspect because of this, they would be using BARALT.
iOnlyCommentHigh@reddit
I donât know how different the Blackhawk RADALT system is, but itâs pretty solid on the Romeo when used over water. I think the only time I had issues was when using RADALT Hover Hold with high seas and even then it only fluctuated maybe +/-5â tops.
TweakJK@reddit
good to hear that, I came from block 1 sierras and Hotels. Our pilots were reporting issues often.
SuperFrog4@reddit
I that an army 60 problem. Navy H60 radalts are the gold stand of accurate and 99.9% reliable. I had 1 flight out of the thousand or so I flew that the radalt failed.
Of course we flew a lot over water so you needed radalt which means we probably bought a better version.
TweakJK@reddit
Its good to hear that from a pilot. I was navy on the 60S and 60H. We had a few problems with them, and the crew often blamed it on the water. You can tell because I said 60H that this was a long time ago.
Username43201653@reddit
And you don't use radalt to navigate relative to other aircraft because the Earth is not flat
i_should_go_to_sleep@reddit
They should have only been using baro as their ceiling. Radalt has no part on the routes. Many times we were flying at 140â radalt or lower to stay below 200â baro because of wonky altimeter settings.
Imaginary_Ganache_29@reddit
Here is the full NTSB breakdown from today NTSB
East_Jacket_7151@reddit
You have to turn the fucking knob to the current altimeter reading from your departure. Either they didnât do that, or there was some huge shift in pressure during the flight.
fanofairplanes@reddit
Didn't set field altitude correctly before departing
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