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| JohnDixson
February 02, 2025, 15:22:00 GMT permalink Post: 11819856 |
Regarding UH-60L altimeters:
All UH-60 A and L Army aircraft incorporated the APN 209 radar altimeter. Our Sikorsky tech fellow for Avioics/electronis reports the accuracy in this area is 1-2 feet. The radar altimeter position in the instrument panel is just to the right of the attitude indicator and its top matches the top of the attitude indicator. The barometric altimeter is immediately below it. Both pilots have the same setup. Subjects
Barometric Altimeter
Radar
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| JohnDixson
February 02, 2025, 17:57:00 GMT permalink Post: 11819965 |
To follow Henra’s on point question: where was the call from the ATC radar monitoring, saying, for example: Army XXX you have traffic, 12 o’clock 1.5 miles coming at you, make immediate left turn to YYY, climb to WWW??
The reporting made public to date leaves the impression that ATC in this instance is the tower controller and only the tower controller. Is it possible that radar guidance ( to either party ) has not surfaced because the single tower controller was not ( possibly could not? ) monitoring the tower radar display ( assuming that there was such ). And, if there was such a display, was there software in place that incorporated a triggered warning when two aircraft tracks predicted an intersection? NTSB will certainly be looking into these aspects. ( An aside re the barometric altitude accuracy fed to the radar system in the case of the non ADSB helicopter-assume this will be part of the after accident homework? ) Subjects
ADSB (All)
ATC
NTSB
Radar
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| JohnDixson
February 02, 2025, 20:59:00 GMT permalink Post: 11820102 |
fdr, unless the Army did a after market install. The L model never had TCAS.
Subjects
TCAS (All)
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| JohnDixson
February 03, 2025, 19:05:00 GMT permalink Post: 11820804 |
From the FAA website:\x93When Radar Came to Town
On January 7, 1952, after five years of testing and modifications to a radar system used by the Army and Navy in World War II, the Civil Aeronautics Administration inaugurated radar departure control procedures at its Washington National Airport. Six months later it began radar approach control procedures at the airport.\x94 How do we connect the dots from 1952 to the tragedy described in this thread? 72 years later we have devolved to visual separation. Subjects
FAA
Radar
Separation (ALL)
Visual Separation
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| JohnDixson
February 04, 2025, 01:56:00 GMT permalink Post: 11821089 |
One more question: Did any of the radars at Potomac Approach Control ( unsure of that title ) have the crash aircraft on their display when the midair occurred and did the Potomac Approach equipment have a warning system triggered by projected intersecting flight paths?
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| JohnDixson
February 05, 2025, 13:43:00 GMT permalink Post: 11822225 |
Dibo/fdr: keep wondering why the Hawk crew made that last correction to the right.
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| JohnDixson
February 05, 2025, 15:40:00 GMT permalink Post: 11822300 |
Pat I was referring to the ground track change. At their altitude, it wasn’t something that would be unnoticed.
Just thinking: they are coming up on the extended centerline of 33, and keep going? Were there any tower or CRJ transmits that indicated the CRJ was on short final? Last edited by JohnDixson; 5th February 2025 at 15:59 . Reason: Added thought Subjects
CRJ
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| JohnDixson
February 05, 2025, 20:18:00 GMT permalink Post: 11822515 |
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. Subjects
Route 4
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| JohnDixson
February 05, 2025, 21:25:00 GMT permalink Post: 11822548 |
CC-sorry I was not more precise: I meant, or was addressing, the point just before the midair-weren’t those communications earlier?
Last edited by JohnDixson; 5th February 2025 at 21:28 . Reason: spelling Subjects: None No recorded likes for this post (could be before pprune supported 'likes').Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| JohnDixson
February 06, 2025, 13:35:00 GMT permalink Post: 11822990 |
fdr, bdcooper et al. The L model ( and original A models), come standard with dual SAS and airspeed hold/attitude hold and heading hold. No separate buttons for airspeed hold etc-its built into the AFCS.
Now the M model is equipped with additional features so you can if wanted have a hands off approach to a hover ( any hover height ) at any preselected destination of your choice etc. M model came after I retired so I\x92m not expert on that operation. The L model in this accident has the 3400shp gearbox and bigger engines, thus with say full tanks and three crew, and as I recall we increased the tail rotor authority. In any case, coming to a hover OGE or any other maneuver you had in mind doesn\x92t present any problems. HOGE/backwards 45 kts-whatever-have at it. Only other thing that may deserve a note is that I do believe ( subject to correction from current Hawk pilots) that they would be using NVGs which flip up so they may have them on, but can choose whether to use them. Subjects
Hover
Night Vision Goggles (NVG)
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| JohnDixson
February 06, 2025, 15:40:00 GMT permalink Post: 11823064 |
SAS-re the gunner’s and crewchief seats being occupied-on marketing demos I’d always have crew members in each seat as lookouts. As you were thinking…maybe an additional set of eyes in the left hand seat would have helped.
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| JohnDixson
February 07, 2025, 10:47:00 GMT permalink Post: 11823540 |
Torque, the 60L does not have Bar alt AFCS mode. It does have attitude, airspeed ( merged ) and heading hold ( with coord turn. ). M model has everything.
Brigadier, the newer NVGs are flip up, so you can have them on your helmet but flip them up if not wanting to use them. Last edited by JohnDixson; 7th February 2025 at 10:52 . Reason: added note Subjects
Night Vision Goggles (NVG)
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| JohnDixson
February 07, 2025, 14:42:00 GMT permalink Post: 11823692 |
The capitol cities of both Great Britain and France both have heli-route structures, and both have good radar coverage ( at least they did 20 years ago ). Depending on traffic, they’ll hold you at one of the check points. And the reason we can only have eyeball control in our capitol is…………..?
And, oh-forgot to mention: if one ignores the radar controller’s instruction to hold, said helicopter is met by the law ( least-thats what happened to a guy I was following in Paris, who blatantly ignored a hold command at Bagnolet. By the time I arrived at the Le Bourget helipad his ship was surrounded by gendarmes and a black van. Last edited by JohnDixson; 7th February 2025 at 14:52 . Reason: added info Subjects
Radar
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| JohnDixson
February 07, 2025, 17:33:00 GMT permalink Post: 11823798 |
The Thames going by the Battersea Heliport is narrower than the Potomac, yet they do two way traffic. Is there an underlying reason why radar control of traffic on the DC heliroutes is a forbidden subject?
Subjects
Radar
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| JohnDixson
February 07, 2025, 18:03:00 GMT permalink Post: 11823821 |
But, S-S, if the two flying machines we are discussing were under radar control, the accident would not have occurred.
Subjects
Radar
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| JohnDixson
August 01, 2025, 16:31:00 GMT permalink Post: 11931930 |
Amen Lonewolf, re the non argument incl bridges and obstacles. And, as I recall, the 209 accuracy is either 1 ft or 1.5 ft.
Last edited by JohnDixson; 1st August 2025 at 19:32 . Reason: old/out of date Rad alt number Subjects: None No recorded likes for this post (could be before pprune supported 'likes').Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| JohnDixson
August 06, 2025, 17:31:00 GMT permalink Post: 11934263 |
Washington National Approach Control is supposed to incorporate a Conflict Alert system. Was the system functional when this event occurred?
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| JohnDixson
August 06, 2025, 18:23:00 GMT permalink Post: 11934302 |
Thanks, BFSGrad-missed that\x85.Guess I was expecting resultant \x93 PAT25 you have traffic at\x85distance and altitude\x94.
Subjects
PAT25
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| JohnDixson
August 06, 2025, 19:27:00 GMT permalink Post: 11934326 |
Is it time to think about the now non existant Heli-route#4 and the other DC area heliroutes?
Paris and London have heliroutes. Been awhile since flying both of these, but my recollection is that they were tightly managed by theATC folks with radar. Ignore their instructions and be met by the gendarmerie ( at least thats what happened to a pilot in front of us who ignored a hold at Bagnolet instruction -when we arrived at LeBourget, the cops had him, and there was a big black van awaiting. The FAA might look into these two examples. Subjects
FAA
Radar
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