YHM General Hospital Helipad question

[...]

Due to construction @ the hospital....the pad has been moved to the roof about 200 feet high...what approach aids are available to the pad during low vis days or nights? How do you rotor guys and gals @ Canadian choppers manage the new pad with higher winds etc etc....?

[sky's the limit]

Birdy,


A pad on top of a building is generally treated as a "pinnacle" landing. This means understanding how the winds behave around the building in question, and flying an approach that avoids the turbulent or down flowing air. Building approaches aren't generally difficult compared to many of the places you regularly land in mountain operations - they can get very interesting indeed.

The S-76, is a pretty powerful, twin engined machine, and the pilots will probably fly the approaches much like off-shore rig guys/gals do, ie. steeper approach path, very controlled rate of decent, and a designated MAP. Cat "A" departures in twin engined IFR helicopters are a bit different than normal, you vertical up to a 'decision point,' 30-50ft depending, then rotate forward to gain airspeed and altitude, and then transition to instruments if required. While I've never flown the S-76, I have flown the Bell 212 in IFR operations, as they say in Vietnam, "Same, same, but different...."

You want to try a "black hole" departure in the arctic, it's actually worse than in an airplane as you have no forward speed initially, and you're in an unstable machine. There was a very nasty and unfortunate fatal accident up in NU about four years ago now, night departure, big snow ball, low vis and ceilings, lead to a loss of situational awareness and they augured in on the ice.

Hope that helps,

stl

[rotorfloat]

I'm sure those eleveated pads are vfr only so if weather is ever an issue, they'll just divert to the airport and have a ground ambulance complete the transfer.

When you get doing that kind of rotary-wing flying, it ain't seat of the pants or bush flying anymore. SOPs are published and adhered to. Every takeoff is crosschecked with the appropriate WAT chart and decided accordingly, full briefings and so on....

One of my friends did the Canadian EMS thing for a while, and mentioned that, on occasion, the medics had to take the cab back to the base because the aircraft wouldn't meet the WAT requirements departing an elevated hospital pad. Sure the aircraft could do it, power-wise, but according to the chart, it couldn't on one engine, so the medics get shoved.

[...]

Thanks for the two different view points...it still amazes me how those things fly.

Cheers!

IABD

[donut king]

That's a BIG negative on the steep approaches to a rooftop pad or offshore helideck. 300-400 ROD max....controlled twin engine profile maintaining OEI performance.

The S76A is NOT powerful when OEI!

Careful what is posted here!!

DK

[sky's the limit]

That's a BIG negative on the steep approaches to a rooftop pad or offshore helideck. 300-400 ROD max....controlled twin engine profile maintaining OEI performance.

The S76A is NOT powerful when OEI!

Careful what is posted here!!

DK

Steep and fast are two different things. Nobody said fast.

The OEI profile requires a much steeper approach than a typical flat approach used elsewhere in the industry. The landing decision point is the commitment, and the 300-400ft/min rate gives a relatively steep approach profile thereafter.

I can assure you, I'm very careful what I post here, and unless all my training and flying has been wrong, that's my best description of what I do/have done in the 212 which I'm willing to bet is even further behind the curve at MAUW.

Hope that clears it up, but feel free to post your best description of a typical profile as I may not be getting it across properly.

stl

We often used to use the 500ft and 50kts, 400&40, 300&30, and so on, works well while maintaining missed option.

[donut king]

I cannot speak in regards to a 212. I thought the thread pertained to the S76 at Ham. General?

I have flown the ambulance in Ontario (S76A) and am presently offshore with S76's also.

Maybe confusion in semantics?

Basically we approach a helideck/ rooftop pad in a similar fashion with the S76. Slowing to 35 KIAS and roughly 300fpm sink rate we maintain a profile to arrive over the deck.......not hovering up to it. Many inexperienced drivers will slow down too much and end up hovering up to the deck. 35kts is the S76's minimum OEI speed for level flight.....given observance of the WAT charts off course. Cyclic flare to arrive over the deck and if you've timed it properly, tq will pass through %55 over solid real estate! %55 being roughly half of 2.5 minute OEI tq of %110.

All in all, it must be a very controlled and stabilised approach profile.

Hope that sheds some light on S76 approaches to decks.

Must emphasize that the S76A does not have new technology high horsepower engines. Therefore it must be flown "by the numbers". Ask any other offshore pilot operating the A model in the tropics. It is not a forgiving aircraft but will perform when operated within it's tight margins.

DK

[sky's the limit]

I think you're right, semantics.

We're both getting at the same thing. As I said, I've never flown the 76, but I hear the A model is pretty lean on the power.... With the 212, the fwd speed following my previous example would be 10kts at 100ft, but given that profile, you can nose over and gain airspeed in the event of a late engine failure. I've never done an approach ending with a large cyclic flare, but that's just in my experience on 212, I'm sure things are quite different with different types. I imagine the S92 boys and girls can approach on one for fun.....!

You with CHC then?

stl