Practice Autos from 100FT / Hover

[Old Man Rotor]

Night Pilot.....

I take your point about the size of some decks....and sometimes we have to take what we can get!!!

The photo from Blender certainly suggests that not all 206 ops are from those tiny decks. Sure sometimes you may not have the extra deck space to use....but if you have, get the IGE in your favour by placing the leading edge of the disc over the departure edge of your deck....don't waste that IGE.

The "Length" or "D" value of a 206 is 39.29 ft or 11.95 M....considered a 12 D aircraft......sorry after 15 years I lost 10 inches!! [Had to get the old notes out thou]

I must take issue with you regarding the logic of operating at 100% and waiting for nature to blow a puff of fresh air to get you flying. I'm not saying it doesn't happen in practice.....but if your at 100% and IGE and not flying.....mate your too heavy.

The logic of doing that in a B412 is horrific and not the best Industry Standard.....try convincing an Insurance Company Lawyer in Court that you crashed due to you not being able to climb vertical, committ from around 15 ft above the deck and safety avoid the deck, and things under the deck after one PT 6 does its own thing.....whats done, whats talked about, whats legal, and what the court decides are all different.

Try using OGE weights as a upper limit for deck departures, and reduce this weight by a factor of 500 lbs if the deck is less than 50' AMSL...eg a Workboat, MSV Seismic etc.

[GLSNightPilot]

OMR, try operating at Cat A gross weights here, & you won't last long. In the summer, at 90+ deg F, you're expected to operate at max certificated gross weight. OGE does not apply at all, and if you can't or won't fly the load, they'll get someone who can & will.

On an offshore platform, indeed any elevated helipad, if there is any wind at all, even a couple of knots, the best way to get off is to get the rotor over the edge of the deck, and allow the wind, which hits the side of the platform buildings, etc, then blows up, to blow up into the rotor & provide lift. You'll get off with less power than trying to hover with the edge of the disk over the helipad, theoretically IGE, but really with a wind blowing down on you as it curls over the edge. It's critical to keep the controls as still as possible - moving the collective up & down will ruin it, as will stirring the cyclic. This isn't anything new - the technique has been used since platforms were put offshore. Interestingly, this doesn't work as well with the S76, apparently because of the different rotor design. In the S76, we get to the edge of the deck on the wheels, with the nosewheel as close as possible to the edge, then pull all available power & ride it on up & out, you can feel "the bubble", and you try to ride it up. If it won't go, just put it back on the deck & either try again, try in a different direction, or as a last resort, kick off some weight. But that's an absolutely last resort. In Europe, maybe you can do what you advocate. But here, the oil companies will run you off in a heartbeat if you can't carry the max gross load. Things don't work here like they do in Merrye Olde, as far as I can see. As for the insurance company, if you're within gross weight & CG limits, they'd have a hard time refusing to pay. I've never heard of a problem in this area. Cat A is specifically not required for offshore takeoffs in the FAR's, so if you're legal, I don't see how the insurance company can weasel out. Again, this is not the UK, and UK rules and legal requirements don't apply.

[Old Man Rotor]

Night Pilot.....

Your points are worthwhile.......all be it far from the [Non GOM] Offshore Industry Standard.......

Try taking such a risk [commercial attitude] where I fly and you would certainly not be allowed back.....and that would be an Oil Company Statement....Loud and Clear.

I can also remember the good old days of hovering, facing 180 degrees off heading in nil wind.....and minimising your left [power consuming] pedal until you were Committed.......how ones viewpoint changes with time.


Its sad that there are still parts of the world that "Managers" demand/expect pilots to fly along the edge....and threatening them with replacement???...what a shame.

PS....I never mentioned CAT A......I did suggest that OGE weights will normally give you "some" vertical climb performance in nil wind.....but thats not CAT A as you know.

[PPRUNE FAN#1]

GLSNightPilot: With regard to Old Man Rotor's sniffing and dismissive comment about how Gulf Of Mexico operations are not up to par with "the [non-GOM] Offshore Industry Standard....."

There have been underpowered, heavy twins such as the Sk-76A operating in the Gulf Of Mexico for at least a couple of summers now, eh? I suppose one could ask how many total accidents have occured in the takeoff phase of flight where an aircraft went in the water whilst it could have flown merrily away had it been at some lighter weight?

Secondly, Old Man Rotor states:

Try taking such a risk [commercial attitude] where I fly and you would certainly not be allowed back.....and that would be an Oil Company Statement....Loud and Clear.

I wonder which oil companies that would be? ...Royal Dutch? BP? Exxon? The same ones that GLSNightPilot likely flies for in the GOM? Funny how their standards change to suit the regulatory requirements of the country/area they're operating in.

Finally, I cannot resist this one. GLSNightPilot wrote about having to operate from small decks offshore. OMR chimed in with:

I take your point about the size of some decks....and sometimes we have to take what we can get!!! The photo from Blender certainly suggests that not all 206 ops are from those tiny decks.

Gave me a right good guffaw, it did! If anyone thinks that decks that size are the norm in the GOM, he's got a few misconceptions about the industry.

[John Bicker]

Just to go back to the 100' Hover and subsequent autorotation. Has anybody considered the following:

Chopping the throttle in an Allison is not the same as a failure. The engine could take as long as 5 seconds to achieve IDLE power. Any less than 2 and you have a problem and can risk a flameout. Everyone still does the slam decel test don't they? At idle the engine can generate from memory as much as 30 HP. I would guess that in this maneuver there could be a lot of HP still around to make it achievable and able to be demonstrated. It ain't the same when it really stops!

Flick the fuel valve off and have a go next time, adds a bit of suspense as well since you don't know exactly when it will stop.No big deal since a power recovery isn't really much of an option in this maneuver. I think you will get a huge fright yet it still may be doeable considering the adrenaline quantities involved.

[Red Wine]

John...............

Thats an interesting point...............A while ago there was a post here about a Melbourne [Australia] CFI who had a ?? throttle cable problem and could not lower the collective without overspeeding [maybe a governer] [H300]......he climbed into CTA trying to get back to his airport...over the top he asked his student to select idle cut off with the mixture control.

The power of the yaw and other aspects of really having NO engine surprised him, and that is dispite him doing thousands of "practice" failures.

[Old Man Rotor]

Night Pilot.

Your assumption about the UK industry is a guess.

Did'nt think there were any B412's in the UK???

Maybe the GOM [we called in the FGOM] when I was in MC, has changed a little, but the operation of the mediums then was quite normal, no high pressure "Get it done Attitude".

We called our SK76's "Medium" class of helicopter rather than "Heavy"....

Presently we utilise three limitations when operating 412's as far as AUW is concerned. Our Take Off Weight must be the lessor of:

1. MTOW [11900 lbs]
2. WAT Chart [Limitations Section of the RFM]
3. OEI capacity at MC or 30 mins to maintain zero % climb gradient at 500 agl [VFR]..... or 1% climb gradient at LSALT in IFR.

There the "Legal" limitations....

Inhouse ones regarding limiting deck take offs to OGE weights [as previously discussed] are based on a common local industry standard. Both client and operator [Government folk are not in this loop] support this standard.

Depending on what model of 412 you have the pleasure of flying.....in an SP, the WAT Chart would not allow you to take off at 90 F at full Max Certificated weight...I assume your meaning MTOW.....if your in an EP, then your smiling all the way home.

[BlenderPilot]

John B. and Redwine

You both have good points which were previously mentioned, is no secret that when the engine actually quits, things are much different than just rolling the throttle to idle.

Now imagine if pilot who has never practiced the previoulsy mentioned autos gets an engine failure on a tough spot . . . . . my guess is its not gonna end pretty.

At least if everyone got to practice this type of manuver at least once, then maybe you can at least have an idea of what it feels like and TRY to do something about it.

Remember there are many pilots who spend a lot of time hovering in the dangerous area of the HV diagram, even if you try to avoid it, suppose you are taking off from a pad like the one in the picture and the engine decides to quit just as you are off the pad? What would most pilots do? Its a normal operation for many pilots to use these pads, its better to be prepared.

Look at my webpage

http://homepage.mac.com/helipilot/he...toAlbum15.html

GLSNightPilot

I'm confused about something you said,

The point of doing this is to simulate an engine failure on takeoff from a platform - most offshore platforms are in the general neighborhood of 100'

The technique is to get the pitch down (not in a huge hurry, certainly not as fast as you can) and lower the nose a few degrees. In 2 or 3 seconds, the RPM in a 206 won't decay all that much. There is no negative G load, unless you screw it up. If you get the entry even close to right, you end up in a normal auto, with just enough airspeed on the bottom.

I've done this in the 206, & do it annually in the 412 and the S76.

You said in as quoted above in one of your previous posts that you have done this before in the 206, and that starting from around 100 FT you then go for airspeed to achieve "just enough airspeed on the bottom" for a normal auto? Are you sure about this? I think if you try to go for airspeed from a 100FT hover to try to do a normal auto you are going dive into the ground nose first. I'm just thinking somebody could read this and leave thinking they could get away with something like this.

[John Eacott]

Did'nt think there were any B412's in the UK???

OMR,

The Griffin is used for mil training in the UK, details here.

[PPRUNE FAN#1]

John Bicker mentioned the "scheduled decelleration" of the Allison engine and he is correct. However, while the C-20 series has this characteristic, the more powerful versions (C-28, C-30, C-47) do not. They *do* however produce some horsepower, even at "idle" as has been noted. It is generally accepted that this "residual" horsepower does help in a practice auto.

If it is that important, the only way to truly simulate the torque-snap and sudden r.p.m loss of a real power failure in a 206 is to do it in a later model Bell 47 with a no-bar kit and the metal, high-inertia blades. These ships, especially a wide-cabin G-4 fly surprisingly similar to a 206B...up to about 80 kts, of course

Here is the thing about engine-failures whilst inside the shaded area of the H-V diagram. You must be ready for them, period. Your hand must be on the collective and you must not let the failure take you by surprise. Your reaction must be immediate and correct. It goes without saying that you must also be into the wind and have a decent landing area right underneath you.

To Blender, I'm sure you must realize that if you are operating from a rooftop structure such as that in your photo, an engine failure on takeoff is going to put you in a very bad situation. I'm sure you've rationalised this or come to terms with it in some way. You cannot control the thoughts/actions of other pilots, so do not worry about them. Just make sure that if the donk ever quits on you that you are up to the challenge and can put the aircraft down safely (hopefully without getting run over by a crazy Mexican cabbie). Maybe you'll bend it...maybe you'll get lucky and not.

[GLSNightPilot]

Blender, I didn't mean you get as much airspeed as you'd have in a 'normal' auto, I meant enough for a successful auto. There won't be much, and I don't mean dump the nose, either. We're talking about the same thing. And I agree with you completely about the practice - even though a real engine failure will be different from, & worse than, a practice auto, slightly unreal practice is better than no practice at all.