Posts about: "Route 4" [Posts: 113 Page: 2 of 6]¶

Yea, I wanted to be generous with that separation.
So even if the helicopter stays in its route 4, bellow 200 ft MSL, they just can't fly directly bellow the approaching aircraft.

'See and avoid' at night over a well lit city is absurd, I agree.

Another iootionto make it safe was suggested elsewhere. Have an either/or arrangement.

If an airliner is on approach to runway 33, Heli Route 4 is closed.
If a helicopter has had approval to fly along Route 4, the approach to Runway 33 is not available.
Simple and straightforward?

Helo Route 4 itself is not inherently unsafe; operations of route 4 AND arrivals on RWY33, DEP 15 are high risk, and always have been. (04-22 is also a potential issue). There are sound reasons to have helicopter operations that are predominately over waterways. It is improbable that the activity rate of helicopters will diminish, the potential to cause another crack to open up in the system is ever present. The cross runways at Reagan are unlikely to be extended, and they add risk to the types that are operating off them. They have existing RESA issues and limited lengths.

Would suspending all operations of the cross runways not simplify the flow control and traffic management, while achieving the needs of the DOD and the unique needs of DC, without setting up new risks over densely populated areas? The primary runway is fit for purpose, the cross runways do not meaningfully increase operational capacity any more than a well set up series of taxiways at either end of the main runway.

The FAA's response is laudable as an immediate response, but it may not be the best risk mitigation in this case.

Messy: taking an aircraft that is on a straight in approach that is parallel offset from the low level route (4) to instead cross the route south of the airport and then cross on final approach the same route again. If you find that comfortable, then have you heard about an accident recently in DC?

The problem with systemic failures is the come along looking like excellent alternatives until the wheels fall off the wagon and it ends in tears. You have to be lucky 100% of the time, the grim reaper only needs one win.

I'm struggling to make sense of the numbers being bandied about here. Apparently the NTSB has said that the CRJ was at 375 feet,

But from the beginning, various plots have shown the collision occurring in mid-river. A little work with Google Earth will show that the extended 33 centre line reaches mid-river about 3,300 feet from the aimpoint of runway 33. A 3 degree glideslope and some trig will put it at 175 feet at that range, with obvious implications. 375 feet would be a big error with not much more than half a mile left to run.

What am I doing wrong?

Also, helicopter route 4 hugs the eastern bank of the Potomac until Goose Island and doesn't cross to the western bank until Wilson Bridge. So why did the Black Hawk perform a 45 degree right turn while still abeam DCA? (See, e.g., post #25) Was it intending to route direct to Fort Belvoir, ignoring the heli routes? (I think I've seen it was operating out of Joint Base Anacostia en route to Fort Belvoir, so the fact it was still abeam DCA must have been more than obvious.)

Puzzled.

I know I'm fighting a losing battle but here goes.....

What you are doing wrong is making guesses based on incomplete/inaccurate data that is in the public domain.

Assuming the NTSB figure of 375ft is correct, you still need more info for it to mean anything. Was that the AGL, AMSL or SPS height/altitude?
How accurate are the 'various plots' that indicate the collision occurred mid-river? They may be right; they may not be.
Was the CRJ on final or was it still positioning to final? If it wasn't on final then the trigonometric calculations of what height it should be at might not be correct.
What official evidence is there that the Blackhawk made a 45 degree turn, or could that be a data error in the publicly available information?

In summary what I am saying is that, despite all of the internet sleuths plotting tracking data, none of it is official and it is all subject to various errors. Whilst interesting to form an understanding of the circumstances, it can't be assumed to be accurate to within a few feet (vertically or laterally).

That 1-2 feet error would be a theoretical accuracy. The readout in the cockpit would be subject to significant errors during turns/pitch changes etc; without knowing the exact installation on a Blackhawk, it might also unlock based on the surface conditions. More importantly, the ATC instructions would probably be based on an altimeter setting and not Rad Alt.

How would that have worked in this scenario? Who do you think should have been directed by TCAS to do what? Does the Blackhawk even have TCAS?

Regarding the collision of American Eagle JIA342 and Army Blackhawk PAT25, I lay the blame squarely on the shoulders of both the FAA and the United States Army Aviation Branch. If the NTSB in any way blame the pilots in the incident, they are not doing their job. Let’s look at all of the holes in this swiss cheese:

1. In an effort to maximize commercial air traffic in and out of DCA, the FAA has created the “deviate to RWY 33 procedure” for air traffic in-bound to RWY 01. This requires a right-hand turn from the RWY 01 approach followed by an immediate hard left-hand turn to line up on RWY 33. FAA criteria for a stabilized approach states that you have to be stable at 500 feet AGL on final in VMC or perform an immediate go-around. But on this particular approach, you will be at or below 400 feet AGL as you come out of the left turn to final. So the FAA has granted an exception to the “stabilized requirements” at DCA to allow for this maneuver. This allows ATC to shorten the distance between arriving and departing aircraft that are utilizing conflicting RWYs. The FAA in essence violates its own safety standards on stabilized approaches for the sake of expediency.

2. The FAA creates the Route 1/4 helicopter route through the DCA airspace as a VFR route with constantly changing altitude requirements. The lowest limit is at 200 ft MSL through the area east of DCA. Any pilot will tell you that flying that low over water at night is a best a tense experience. Try not to break that limit flying at night while also trying to communicate with ATC and simultaneously searching for possible conflicting aircraft.

3. The United States Army Aviation Branch deems it acceptable to allow training missions for Army Reserve pilots with limited flying experience to fly these helicopter routes through this complex and extremely active airspace. Compounding this, training flights at night using night-vision goggles are deemed “safe” in spite of the fact that using said goggles severely limits peripheral vision and makes it difficult if not impossible to perceive any color other than green and white. Picking out particular lights against the background of urban lighting is challenging, as is depth perception. Scanning key cockpit instruments is also made more difficult, making it challenging to accurately maintain altitude. Add to that workload the need to be in constant communication with ATC as well as monitoring all other comms traffic not directed to you but necessary in order to maintain good situational awareness. Given the density of commercial air traffic on this route, common sense would dictate that this route be flown by only the most experienced pilots and only when absolutely necessary. Reasonable logic would understand that conducting training missions should not be using final approach areas with heavy commercial traffic.

4. The Army crew on PAT25 are flying a mission they have been ordered to fly, at night and using night vision goggles. Although they may feel it is difficult and may be anxious about it, their command structure has determined that it is an appropriate training procedure and as such must meet minimum safety requirements. They do not have the authority to question the mission or the orders to fly it.

5. JIA342 is on approach for RWY 01, but is asked at the last minute by ATC to deviate to RWY 33, requiring the “circle to land” maneuver. Therefore, they are now on approach different from what they briefed for.

6. Any aircraft following the “circle to land” approach to RWY 33 will most likely have both pilots focused on RWY 33 as they come out of the left turn to final, especially if it was a last-minute request by ATC. In this case they will be looking to make sure that AA1630, which has just been given clearance to depart from RWY 01, is clear of the intersection with RWY 33 as they complete their final approach, and be ready for a go-around if it is not. In addition, this left bank makes it extremely difficult for the first officer to see any conflicting traffic coming towards them from the 1 to 2 o’clock position, as that traffic will probably be below the right window level. For the pilot, who is on the left side of the cockpit, visibility of such conflicting traffic will be nearly impossible.

7. For whatever reason, ATC is working with “split frequencies while controlling this airspace, so that although the controller hears both the aircraft on approach and the helo traffic south-bound on “Route 1”, the pilots of those respective aircraft only hear information directed at them. Thus they are not aware of all that is going on around them, and as such their situational awareness is limited by factors outside of their control.

8. ATC informs PAT25 of the conflicting aircraft on approach for RWY 33 at 1200 feet MSL, but at the time, PAT25 is heading almost due east towards the Jefferson Memorial on Helo Route 4 while JIA342 (the CRJ) is executing its right turn departing from the RWY 01 approach and is now heading in a northeast direction as it prepares to make a hard left onto the RWY 33 short final approach. From their respective positions, PAT25 in all likelihood sees the landing lights of AA3130 which is trailing JIA342 and whose landing lights are pointed almost directly in his direction, and mistakenly identifies it as the aircraft approaching RWY 33. At no time does it appear that ATC notifies JIA342 of the conflicting helo traffic. They are most likely focused on their approach to RWY 33, which was just handed to them.

9. As JIA342 rolls out of its left hand turn to final on RWY 33, completing the deviation they were just handed and had not briefed for, it is now approaching the 9-11 o’clock position of PAT25. Since the pilot of PAT25 is on the right-hand side of the Blackhawk, visibility of the CRJ may be limited. Both pilots of PAT25 are now most likely visibly fixated on passing to the rear of AA3130, which is in their 1-3 O’clock position, and which is the conflicting aircraft they perceive as the one ATC initially warned them about.

10. ATC, now receiving a conflicting aircraft warning, asks PAT25 if they have JIA342 in sight. In the absence of any obvious difference from the first mid-identification of the conflicting traffic, confirmation bias raises its ugly head. The voice response from the training pilot is calm and confident in stating that they do have it in sight and claim visual separation, probably proving once again that he mistakenly has AA3130 in sight slightly to his right directly in front of him and more than a mile away. Both pilots are totally unaware of JIA342 which is now arriving in front of them from their left.

11. The collision occurs.



In my humble opinion, the crews of both aircraft involved were set up by both the FAA and the Army Department of Aviation through a series of poorly based decisions which focused on expediency and departed from any appropriate utilization of a rational use of risk assessment. Consider the following:

1. Approval of the circling to RWY 33 maneuver which violates normal stabilized approach standards.

2. The establishment of a series of complex VFR helicopter track complex and heavily restricted air space as well as through final approach paths.

3. A 200 foot maximum altitude requirement over water and required even at night, which may result in a less than 200 foot vertical separation between aircraft on approach to RWY 33 and those traveling on Helo Route 1/4.

4. The decision to conduct military training missions in this complex and busy airspace with an abundance of commercial passenger traffic either arriving to or departing from DCA.

5. The use of split frequencies by the FAA which negatively impacts the situational awareness of all of the pilots in the airspace.

6. The use of night vision goggles to place even more limitations on the pilots.

Granted, all pilots involved may not have had the thousands of hours senior commercial and military pilot possess. But even the most senior individuals when placed in the task saturated environments these two crews faced would have at the very least felt their “pucker factor” increase through this. And there is probably an equal chance that the lack of common sense and appropriate safety design exhibited by the controlling entities would have resulted in a similar outcome. The odds were significantly stacked against these two flight crews, and unfortunately, against the passengers and flight attendants as well. If ever there were an example of an accident waiting to happen, this is it.

patrickal, very good argumentation! I have though one question, which was highlighted also some pages before but I didnt register an answer:

I fully sign your deduction, but granted your assumptions are true that PAT25 was mentally focussed on passing behind AA3130 (which I fully believe too), but they also received the information that it is RWY33 that is to be used for landing of the CRJ. So why for gods sake did they continue into 33 runway extension before AA3130. Was there also a disorientation towards their current position relative to DCA runway systems and they also easily (at night, mental bias) took RWY01 for RWY33 ? It almost looks so. Once more the narrow vision of NVG cheese slice ?!

If people (and even 'reliable Youtubers') would stick to the available facts, instead of complicating things
No crossing of 'Route 4' prior to ...

Still, if the helo crew misidentified the A319 as the CRJ, and they assumed the A319 will start turning right soon to circle for 33, turning right as well would have increased horizontal separation. And the extended centerline for 01, which the A319 was aligning with, does actually intersect with Route 4 a bit after the Wilson Bridge. And, looking at the radar replay, the A319 did actually turn right for a bit, to align to 01. At around the same time, the helo starts turning right.


I agree that these are just guesses, but the alternative seems to be that the helo just drifted to the right randomly, for no specific reason, which seems unlikely.

Well I only replied to the CRJ not crossing "Route 4" as some people paint on screenshots...

the A319 was adjusting a few degrees left and right, but wouldn't call that 'turning' (but of course its position would make it an ideal target for misidentification)



Well, it's probably my worn out eyes, but I don't see really any reliable evidence of the helo turning right ... remember it came out of Route 1 which ends in one big right-hand turn until joining Route 4 which only after passing KDCA airfield, has a very slight course adjustment to the left.

And the "amateur MLAT" tracking of the helo, is only a rough indication of the trajectory with a wide margin of position error and should be interpreted more like the right side hereunder:

Could they have been over-correcting for a quartering tail wind from their right which was at 15mph gusting to 25mph? That's not insignificant.

One major fact: the wreckage is located in the middle of the river, west of route 4. SA question is, what lateral separation image had the helicopter crew in mind trying to stay behind the jet, possibly focussing on the second jet on approach to 01.

Thanks, it appears that the internet may be passing misinformation, albeit with the best of intentions.
That had occurred to me as well; not the right environment for flying on goggles.
Thanks for that insight as well.
It's almost as though wearing the NVG in the vicinity of the airport on that evening would, by itself, create a degraded lookout ability. Seems counterintuitive unless one gets into the details of how NVGs work.

I don't think it make a significant turn right, and I believe that what you are seeing is positional inaccuracy due to MLAT position limitations in the ADS-B Exchange data. According to Flightradar24, " MLAT position calculations have a general accuracy of 10-100 meters and 1000 meters in the worst cases." Given that, I believe this previous post from MikeSnow AA5342 Down DCA represents our best current understanding of the actual helicopter track and its relation to Route 4 (until we get more information from the NTSB). I generated my own zoomed overlay and got essentially the same results



The position of the collision shown in the radar data overlay is consistent with the position of the RJ as shown in ADS-B Exchange at the time of the collision (approximately 01:47:59Z according to the NTSB timeline). See this link from DIBO for the RJ Track with timing AA5342 Down DCA In my experience, times in ADS-B Exchange are generally accurate to within 2 seconds. Given all that, I believe that the Black Hawk was within the horizontal bounds of Route 4 at the time of the collision and that it did not make the right turn we see in the ADS-B Exchange map.

Edit: Corrected route number and helicopter

LW, I think I read at some point that the Route 4 instruction reads at or below the 200ft number…but yes to your post.

The other thing that comes to mind is along the lines of: OK I’m coming up on the extended centerline and haven’t heard a call from the traffic, and haven’t seen it, and yet I proceed as if the traffic was either short final or landing, or way off to my left , so far away I can’t see it? The Hawk doesn’t query the tower re the position of the other traffic? Think I saw a reference to the Hawk having a FDR/CVR-had to have been an aftermarket install- and that voice record might be illuminating.

Last thought: over some years I’ve had the pleasure ( several times each location ) of flying the heliroutes at two other capitols: London and Paris. Both are a pleasure to fly and tightly controlled. As one might imagine the amount of traffic when the Farnborough or Paris Airshows are running is impressive, yet they know where all of their traffic is and the associated commo is handled so as to provide no doubt about other traffic as it affects your place in the operation. The story we are uncovering here is a shock.

Condolences to all impacted.
Questions:
Why was PAT 25 search light in the stowed position and not motored to a more forward position?
Why are PAT helicopters not M models with FD's so PAT 25 could have been coupled on route 4 while at 200' giving the PF more time to look for traffic?
Was there pressure to use NVG along route 4 to meet the hourly requirements for currency?
Why did PAT 25 not slow down or hold at Hains in order to pass behind the CRJ as per their clearance?
Why was it ops normal after a near miss the previous day and then only one crew chief instead of two for PAT 25?
Why was the controller task saturated?
Why over the years, as the airport got busier, someone didn't suggest, for night operations, only one aircraft on route 4 or only one aircraft on the approach to 33 at a time and prohibit simultaneous operations?

IMO while the CRJ was turning final to rwy 33 PAT 25 may have experienced the CRJ landing lights in the cockpit and may have chosen up and right rather than left and down. Note worthy, PAT 25 RAD ALT gauge scale changes dramatically at 200'.

Maybe an upgrade to Dulles with a high speed train connection...

By the time the lights were shining in PAT 25\x92s cockpit, it was way too late\x97collision was inevitable and unavoidable.

Not the latest model? Guess what, combat units get the latest models. These missions are transport, not combat roles. Budgets and priorities rule. There are VH-60s in the battalion, they\x92re probably not scheduled for check rides or training flights.

One RA does not rewrite the schedule, likely not even unusual in DCA. The previous crew may not have passed the event on. I\x92ve had numerous RAs, never a report. The NTSB has stopped asking for reports for events involving VFR traffic.

While nice to have, there\x92s no place for a second crew chief to have a forward view. And the CC may or may not be \x93in the loop\x94. They\x92re crew chiefs, not pilots. We had them on C-5 and they mostly slept in flight as they too much to do on the ground.

IFR separation is not appropriate for VFR traffic. Class B airspace has specific rules for separation of VFR/VFR and VFR/IFR aircraft. The helicopter routes do not appear designed to provide the required separation for VFR helicopters, at least where Route 4 and RWY 33 final approach cross each other. Was the design at fault OR was the daily application at fault? If the design was at fault, it\x92s an FAA DOD problem. I find it hard to believe the FAA didn\x92t address the correct separation distances in the design phase\x97it\x92s pretty clear. The FAA may have planned crossing traffic wouldn\x92t happen or there\x92s a FAA LOA defining how crossing traffic would be controlled, but the FAA didn\x92t say \x93okay, let\x92s go with 150\x92 vertically\x94.

Did the FAA or the Army assume they would always be able to apply visual (NOT VFR) separation. Visual separation does not necessarily mean 500\x92 vertically and 1.5 nm or radar target separation; it means \x93I see you, I miss you\x94. Did the operating plan always direct crews to use visual separation as the default plan? I hope not, but it is only I see it being written.

1.5Nm is longer than Rwy 1. Any traffic on the runways basically knocks out helicopters within a circle more or less encompassing Memorial Bridge, Capitol St Bridge, the sewage treatment plant, and Route 5. The approach paths to the two runways are pretty close together compared to a 1.5Nm separation.

Anything approaching Rwy 1 should be below ~700ft anywhere north of the sewage treatment marker; use the Wilson Bridge for a bit of headroom because not all aircraft are going to be perfectly on glideslope.

The river is far narrower than 1.5Nm so clearly a southbound helicopter on Route 4 can never cross a northbound aircraft approaching runway 1 north of the Wilson Bridge.

You'd have to hold a southbound helicopter north of either the Memorial or Capitol St Bridges until previous traffic had landed. Then have a sufficiently large gap with no arrivals (or departures until south of the runways) for the helicopter to reach the Wilson St Bridge before the next arrival crosses that bridge.

That's the preceding aircraft covering ~3Nm at 140kt (~80s), followed by the helicopter covering ~6Nm at ~100kt (another 3.5min), and accurately timing the next arrival so it doesn't cross the Wilson bridge until after the helicopter, or it needs to do a go-around.