How Low Should We Go?

[Bomber ARIS]

FAA Issues Revision to Authorize COPTER ILS Approaches Below 200 Feet


After considerable work between HAI’s Flight Operations Committee and the FAA’s General Aviation and Commercial Division, the FAA now authorizes helicopters to conduct COPTER ILS approaches to Decision Heights (DH) below 200 feet at Category II facilities.

Copter ILS Approach Approval – Authorizations issued after a successful demonstration of this capability provides the holder the authority to descend to a DH of less than 200 feet with less than 1800 feet visibility, while conducting a Copter ILS approach CAT II ILS procedure.
(There are pilot training and certification requirements, as well as aircraft equipage, before authorization will be granted.)

Having flown Cat II ILS procedures as a suitably trained pilot, in an appropriately equipped helicopter to a 100' DH, I was always slightly narked that I was forbidden from flying a Cat III approach to a 50' DH like my, much faster, 777 buddies.

Yes, I know that not many autopilots will take one below 65' and that a 4-axis AP is required (AP controlled collective), but if the authorities would permit parity with the fixed wing world then the TRUE capabilities of the IFR helicopter will be realised.

"Goodbye alternate - Hello increased payload!"

One would hope that the increased reliability (with respect to scheduling) and profitability of the helicopters in question (offshore for example) would more than justify the investment in technology and crew training.

Bomber ARIS


(Maybe those braniacs :8 over at the Comanche dealership could design a portable, disposable, Cat III ILS/GPS point in space approach system that I can throw out the door when I'm IMC, 1000' overhead an EMS scene.

"Goodbye scud-running CFIT :ouch: - Hello safety" )

[HeloTeacher]

Cougar, out of Halifax and St. John's (Canada), have been operating to lower minimums for years now.

Really though, to effectively market IFR helicopters we DON'T need lower minimums. The few extra days of flying each year would only marginally improve performance.

We need IFR approaches to helipads, not runways, more heliport access to population centers, not airports, and effective icing protection/prevention.

With those improvements to the system, we'd be in business.

[Gomer Pylot]

The current Cat I ILS permits this in practicality. All you need is to see the approach lights, and you can continue to 100' above the TDZ, and you can initiate the approach with 1/4 mile visibility. I've flown a number of ILS approaches with the official weather being 100'/.25 miles, and I've never made a missed approach under those conditions. With 1/4 mile vis, you should almost always see the approach lights at 200', and from 100' you should see the runway lights. This is especially true at night. In short, the effective minimums for an unaided, hand-flown approach are 100'/.25 miles, not what is published on the chart.

[NickLappos]

For helos, getting slower at the MAP is critical to lower mins. Remember that airplanes land, then stop while helos must stop, then land! For an airplane, the MAP can be 2 miles from where it finally stops.

The real issue for low minimums to heliports is not the DH, it is the distance from the missed approach point to the touchdown point. This distance is determined by the speed of the helo at the MAP, since only so much decel is comfortable for the visual section of the approach. The speed at the MAP is not significant for airports, since the runway length is all available to let you come to a stop.

For a typical helo at 70 knots, it might take 1/2 mile to stop, so the vis could possibly get no lower than that. The vis affects the DH, too, because if you work up the natural descent angle of 3 degrees, the DH could be above 130 feet.

So we are working on how to get much slower while in IMC so that when you break out, you can just put the helo down. There are two ways to do this, either make the helo able to do it automatically, or beef up the pilot's cues so that he can handle the machine as if it were in visual conditions.

[heedm]

Nick,

For the decellerating approaches, I imagine there is still a missed approach procedure that you can fly from between the MAP and the TDZ. With your airspeed decreased wouldn't it be hard to meet departure gradients? It seems like this would be a significant stumbling block for decellerating approaches.

Matthew.

[HeloTeacher]

Interesting point Matthew, but from my experience I have always thought that approaches are designed around the idea that at DH/MAP you either land or miss. The idea of deciding to land and then missing, to my mind, contravenes that thinking. Even in a traditional approach at some point you are 'committed' to the ground.

And Nick, I agree with that logic. I have always, to this point, been taught in my offshore approaches to reduce airspeed to the minimum certified IFR speed for just the reason you specify, a comfortable transition to the deck. I have found it interesting that the 'newer' stability/autopilot systems have had higher min-IFR speeds than the venerable old Bells I've flown.

It had been reasonably common for us to slow to 40-50 KIAS when the landing area was limited (i.e. hangar beside threshold) to avoid just that cruise past the threshold that you describe. Can you please let me know what has made this so difficult to do in the 21st century? Not being confrontational, just curious.

I firmly believe that it is infrastructure and public education that will allow the helicopter industry to blossom, not new technical advances or whiz-bang features. Just my opinion.

[heedm]

HeloTeacher,

I see what you're saying, but that would require that the decelleration on the approach below a certain speed could only begin after sighting a landing environment. I didn't think this was the case. Also, I was lead to believe that the missed approach procedure was also valid after losing runway environment. Obviously it's your best course of action, but whether the procedure was designed with this in mind I cannot say.

Matthew.

[NickLappos]

heedm,

The idea in deciding to land is that the pilot has decided that the aircraft is in a safe position to land, and that the landing environment is clearly in sight. Letting down below minimums is one of those acts, like pulling triggers and ringing bells, that don't allow any "oh, I changed my mind!" second thoughts.

Yes, you should go back up if you find you really can't land (although in my entire helo career I have flown exactly ONE missed approach for real!), but there is no rock solid procedure that assures that the below-DH-missed-approach will work.

The concept I was shooting for is that the helo approach ends when you touch down, and that for most helos a sizable slow-down is needed from the DH/MAP to the touchdown. This slow down will keep minimums pretty high until we slow the machine down while still IMC. The next boundary we will cross with helos is to become truly VTOL aircraft, and abandon all those airplane procedures and perform a truly helicopter IMC landing.

[heedm]

Nick,

What you say about VTOL is interesting. Since the issue for IF departure is climb gradient not climb rate, then a truly VTOL procedure could demand a 90 degree climb angle. I know there are machines capable of that in cloud, but I doubt if any of them have a large OEI envelope for that procedure. What is the holdup to making this happen? Hopefully it's not just a rules thing.

I've flown a few missed approaches for real. In some of the cases I was able to look straight down to see ground, but couldn't see enough ahead of me to call it a safe landing environment. I.e. Slant range vis wasn't sufficient but vertical vis was. One time we were above a 500' fog bank, could look down to see the runway, but we couldn't fly down to the runway. We considered hovering off the AI with someone calling drift, but then remembered that the hamburgers at taxiway Golf in Nanaimo were a better option. I digress...

I've been thinking through these approaches over the last few days and have some ideas for their design. I wouldn't be surprised if these ideas have already been considered, but just in case I'd like to contact someone in the know. Anyone out there?

Matthew.

[Nigel Osborn]

Just get an auto hover S76 and push the button!!:O