Heliroute Clearances in the USA (DCA)
 

Can anyone tell me what kind of a clearance and ATC service you get on the heliroutes in the DC area when you cross into the DCA class B, particularly at night ?

I've been going backwards and forwards on the DC crash thread, and I've realised that things might be completely different here in the USA than in the London Heliroutes that I'm more familiar with. I think the key bit in the UK is that the service is Radar Control (ie control and separation using radar), whereas I have this horrible suspicion that it's a lot more loosey goosey in the USA.

It seems that visual separation between jet traffic and helicopters is quite normal and in fact the assumed mode of transit (even at night). Obviously that didn't work for this accident. There is a suspicion that the heliroutes in the DCA airspace are really just advisory (no defined lateral boundaries), although they do have mandatory altitudes.

Thanks,
WMF

Pretty sure, there's a Helicopter Chart for the DC area. Just go to the FAA webdite and download it.

DC isn't like everywhere else in the US. Its very restricted airspace requiring "essentially" an IFR like setup to fly through. Everyone gets a unique squawk and must be on an approved flight plan and frequency.

The accident in question was a military aircraft on NVG that had some kind of altitude discrepancy (maybe they had the altimeter set wrong?), plus at low altitude at night, its easy to mistaken one light for another, thinking you have someone in sight when its really someone/something else.

The separation standards and ATC service provision applicable to VFR flight in Class B are all in this FAA link:

https://www.faa.gov/air_traffic/publ...ml/chap_7.html

7-9-4 is where you'll find the separation standards.

Thanks both of you, useful background. What I really need to know on top of this is what actual service is typically offered to transiting traffic on route 1 and 4. I think I can probably infer that it's visual from the subsequent comms. That is the core difference between the London Heliroutes and those in DCA. In London it's Radar service only for helicopters on the routes, with the possible exception of the Battersea LFA. Hard to see why that wouldn't be the same for DCA.

In the States, normal VFR flying (where you're just flying about on your own and radar services are "on request") is designed by the squawk code 1200 (e.g. after transitioning a Class B airspace the tower will say, "Radar services terminated, squawk VFR"). In DC however, that squawk code is not available.

DC is our nation's capital (where all the incompetent rich assholes who run the country hang out) therefore someone is ALWAYS watching you!

I've only flown in that area twice. To transition through, I had to file two flight plans. One to enter the airspace (at a specific point (or gate)) and the other to exit at a specific point/gate. I couldn't even takeoff before I got my special squawk and frequently.

The other flight was a simple reconnaissance flight, that required me to enter Class B airspace. They gave me ten minutes to do what I wanted to do, then I had to leave. Again,...its VERY restricted airspace! :cool:

Class B is not used in Europe, which is probably where your confusion comes from. The starting point in Class B is that ATC is responsible for separating all traffic, including VFR from VFR, so the "type of service" is not really a relevant concept. You must talk to ATC and you must do what they say, regardless of flight rules.

How ATC apply that control to VFR traffic is all there in part 7-9 of the link. I suggest reading the whole part from 7-9-1, including the notes. It's not long and is quite clear, but to summarise:

A) Helos at DCA are VFR in Class B. This means they must squawk and talk (7-9-1) and follow route and altitude clearances given by ATC (7-9-2). This could be a procedural route clearance, but the controller will monitor, separate and sequence by radar (7-9-2a note 2) and may instruct aircraft to hold (7-9-2c). The separation standard is 1.5nm vs large aircraft (7-9-4b1), radar target resolution vs small aircraft (7-9-4d1) or 500ft vertical vs any aircraft (7-9-4b2 and d2).

B) The controller and pilot may agree upon visual separation (7-9-4b3 and d3), in which case the separation minima no longer apply and it becomes the pilot's responsibility to avoid collision. Throughout, traffic advisories must be given (7-9-5) and any vectors given by ATC must meet minimum altitude criteria (7-9-7) which are much higher than 200 feet.

In European terms, my paragraph A) is what you would understand as radar control. The clearance and start of a route through DCA probably reflects your London experience, with a procedural route being followed and the controller keeping airline traffic vertically or horizontally separated by radar. However, as the route gets close to DCA, the separation standards become impossible to achieve. To make progress the pilot must become visual with factor traffic, request visual separation, and be granted it by ATC. If traffic is not sighted then the controller must maintain separation by other means such as holding (vectoring being constrained by the 7-9-7 restrictions at low altitude).

As such, the lateral dimensions of the routes are not very relevant as true "procedural" separation is not used at any point: it's either radar or visual. The maximum heights on Route 4 strike me as a veneer, "safety for show", a paper-thin layer in the Swiss cheese around this accident: a few tens of feet of separation if everything else went wrong. No one can seriously have plotted out the runway 33 approach path and thought that 50ft of separation over the east bank made a valid contribution to a safety case.

The DCA airspace design didn't just incentivise pilots to report visual with traffic and request visual separation: it actively required them to, with no realistic alternative course of action besides holding. In this sort of environment, one can see how pilots might learn to respond reflexively to traffic calls by requesting visual separation to avoid their progress being impeded.

The sort of thing that happens when you don't accept visual separation when required to in Class B is well illustrated by a hotly debated event at SFO a while back. A Lufthansa aircraft refused an ATC request to accept visual separation against parallel approach traffic. Although he reported the traffic in sight, he stated that company policy did not allow him to accept visual separation at night. This left ATC no option for maintaining separation minima besides sending him around and into what some saw as a punishment hold. Lufthansa backed the pilot's decision, but changed their policy as there is no other practical way of operating into some US airports.

So,...Lufthansa will only land on a parallel runway at night, if no one is landing on the other runway? That's a tough policy at busy airports.

Thanks guys, much appreciated. Some studying to do.

I think it is worth trying to get the ATC radio recordings for this one from the different recordings to understand some key issues. (you can find them on You Tube). I have been trying to follow information as it has dribbled out. 1. The ATC to hele radio traffic was entirely focussed on the hele formally requesting and ATC accepting visual separation. From the way the phrases were spoken it sounded a bit like a mantra. That rather supported the suggestion above that all involved were clinging onto "visual separation". Effectively, there seemed to be no alternative to VFR with visual separation. 2. The hele and aircraft involved were on different frequencies although talking to the same controller. Some SA was likely lost as a result. 3. Runway 1 was in use at DCA (presumably broadcast on the ATIS). It was apparently practice to divert some arrivals onto Rwy 33 to allow more departures on Rwy 1. This is what happened to the aircraft involved. On the IFR approach for Rwy 1, ATC asked the aircraft to accept a fairly late change to a circling VFR approach to Rwy 33. 3. From the latest NTSB broadcast that I heard the information received at the hele (recorded on the hele CVR) indicated that traffic information (about the arriving aircraft) failed to communicate to the hele pilots the changed runway (it was transmitted by ATC and recorded on the ATC recording but got lost
by the time it "arrived" at the hele). I think that may be quite key. So, we are left with a low level hele with its crew using NVG looking for an aircraft approaching to the wrong runway. If you look at the charts for DCA, some of the hele routes are so close to the aircraft operating to/from DCA. Sadly the route the hele was on was effectively at the threshold of Rwy 33. NVG-wearing pilots over a densely lit city at very low level looking to the approach of the wrong runway (Rwy 1) for an aircraft on finals for Rwy 33 (with no way of distinguishing betwen aircraft at night) seems like a classic swiss cheese event. All preliminary and subject to NTSB report, of course

And where is the instruction from ATC to the CRJ (now flying a VFR circling approach to 33) to look out for the helicopter?

Seems to me that what had been IFR from VFR separation with the onus on the helicopter to spot the FW visually had now become VFR from VFR separation with no indication to the FW that the helicopter was there.

Might have given them some vital SA.

It’s interesting. The clear difference between DCA and London is that DCA will allow visual separation on user request, whereas London will not. So this is actually less about route design (although that could certainly use a fresh set of eyes), it’s about the practical application of airspace policies. If DCA had not allowed visual separation the helicopter would have had to hold short of the tidal basin for a gap in traffic most of the way to the Wilson bridge.

Other than the Kings Flight, there aren’t really any operators in London with the clout of the Priority Air Transport Unit. The UK CAA has a pretty jaundiced view of (most) private helicopter operators, and I’m sure that would have informed their approach to airspace policy. The result is an efficient, but highly controlled route system.

DCA I suspect allow very few private operators to use this routing, so they have one client with a lot of clout calling the shots, or certainly one client whose employees are incentivised to explore all flexibility open to them.

There’s an interesting parallel between this collision and the 2014 collision between a helicopter and a crane in central London (Butchers Bill 67 vs 2). The CAA threw the book (probably rightly) at the (dead) pilot, and set about dismantling the operator. Not an option with the DCA accident, although there are some signs that legislators are taking an interest in encouraging the FAA to examine the other heliroutes in the USA for similar pitfalls.

Here’s hoping.

The biggest difference is that there isn't low level military helicopter traffic in the London Helilanes, mil traffic has to operate at the same levels and with the same clearances as civ helis (with minor exceptions using barracks LS's for example).

Similarly helo traffic crossing LHR has to comply with very strict clearances and routes - not at low level either.

So someone in the FAA signed off on having dual runway ops (IFR or VFR on one freq) with low level mil traffic (VFR only) on another freq. I would imagine the investigation will look closely at who approved that and what procedures are in place to mitigate the obvious risks.

It looks like airport efficiency (increase in traffic throughput) may have been prioritised over safety.

The CRJ was conducting a visual approach under IFR. However, it's a distinction without a difference under FAA rules, because visual separation can be given against IFR traffic just as well as against VFR traffic. The separation acts one-way, as it were.

Controllers are required to give traffic information to the aircraft against which visual separation has been approved when the flight paths are converging, per 7-2-1.a.2.d in the 7110.65, and per the next rule must advise both pilots if the contacts appear likely to merge. The CRJ should have received both, but got neither.

Oh dear. Another big hole in the cheese there.

Does anyone have a reference to the UK version of the manual that Easy Street referenced ? I know from memory that the London controllers will not allow visual separation unless BOTH aircraft involved accept it. In London this is only applicable in the case of helicopter traffic crossing in opposite directions on a route, and is negotiated between the crossing helicopters by ATC on a specific case by case basis as a precondition of entry to the routes.

This makes sense. Why should you be put in a situation where another aircraft is responsible for your safety ?

As regards London - I think you might be thinking back to the days when it was Class A Airspace. I do recall being asked "can you accept visual separation on the routes?"

It's been class D for some years now and VFR traffic is not separated from VFR traffic - It's only given traffic information. You are no longer asked if you will accept visual separation on the routes - you are told what and where the traffic is and it's your job ( and the other aircraft's ) not to bump into each other. The controllers don't separate you (although they are pretty good at keeping an eye on you and will often give updated traffic information or confirm visual contact if they are uncertain that you can see each other).

Oh well. Just shows that memory is no substitute for the manual ! Thanks.