Autoland capability

[born2fly_au]

I am trying to find out info on a helicopter autoland system. Do they have for example have the capability to set an approach heading to say a helipad with only one way in like 270'. if you are set to autoland and you are approaching the area on a course of say 180' but you need to land in a heading of 270' because of trees. Can a helicopter Autoland system be setup to do this?

[Vfrpilotpb]

No doubt the guys who fly the big stuff will make some comments to your question, but as far as I am aware, many Helis in the more expensive range have Auto pilots that allow route. heading , height,, waypoint turns and bring you down to a spot you have pre logged in, however as far as I know because of the many variations of landing sites and wind direction I do not know of a total auto let down system.
But like you I will be interested in what follows.


Vfr

[Droopystop]

:eek:
Autoland to an obstructed landing site - I'd rather use a parachute!

If there is a helicopter with autoland, I would imagine it has wheels and would be restricted to runways. Maybe the S92/EC225 is so equiped, but at least half the kit is installed on the ground.

[steve_oc]

About the best you will get on a production system (332L2, 155, 225, S92, S76C and others) is an ILS with automatic level off at around 80 feet above the runway and a speed of around 60 kt, tracking the centreline. The 92 can do this as a pseudo-ILS to an FMS waypoint, so with any desired final approach track. There have been a number of trials with GPS "point in space" approaches which provide guidance down to the hover, but as far as I know there are no current production systems which do this.

[MBJ]

If you are thinking of this as a way of making your life easier because you are currently doing it by hand but I can only suggest you stop before it all goes horribly wrong!

The military anti-submarine people used to have systems similar and VERY VERY expensive but even they didn't try to use them to actually land an aircraft but merely to come to a hover over nice unobstructed water.

[Hilico]

I was thinking of asking this very question. In a nutshell, is there Cat 3 for helicopters? I didn't think there would be as there's a minimum airspeed for flight by reference to instruments and Cat 3 is zero ceiling-zero vis - and even the cleverest 4-channel SPIFR setup can't hover. I am willing to be corrected on all the details.

[Matthew Parsons]

I'm not aware of any such capability, but it is possible. Many large helicopters will autotransition to the hover at a desired height. Most auto hovers will descend to a desired height. The bouncy bit at the bottom would take some effort, but I see nothing that puts it out of the realm of today's computers.

The real question is will someone want this capability enough to pay for it? The limitations would probably prohibit operations from all but very open areas. Performance would have to be commensurate with the operation being flown. Failure modes would need to be proven. It wouldn't be cheap.

Cat 3 is good for aircraft on very long flights with very high eye heights that are flown in situations where saying 'no go' is costly and not understood by the customer (ie int'l air carriers). Helicopters have shorter flights, lower eye heights, and customers with a bit of fear that will more quickly accept 'no go'. Almost all IF operators should be able to accept Copter ILS minima. If not then a safe transition to an auto hover over land and then a descent to ~30 feet for a visual landing would appease the remainder.

I'm not saying it can't won't or shouldn't be done. Just that I don't think there's a market for it.

Matthew.

[Thridle Op Des]

Cat III autoland is not zero/zero, never will be since there is still a requirement to taxi off the active and get out of the way of the next aircraft without getting lost on the way. Typically the minimums for Cat IIIb is zero DH and 75m RVR. The way a fixed wing gets down is to fly the ILS G/S and LOC to a certain height depending on the specific type, but somewhere around 100' the autopilot switches from G/S - LOC to Rad Alt - LOC to execute the final stages of the flare and landing. The LOC is very good at lateral guidance at the touchdown point since there is a good distance from the LOC antenna to the aircraft and the LOC signal continues to guide the aircraft down the centerline of the runway via rudder and eventually nosewheel steering. (we have to remember to disconnect the autopilot at the end of roll out otherwise the thing tries to go back to the centerline and a small fight develops). Flare is done by Rad Alt since this is entirely a function of rate of descent and forward speed. The G/S antenna goes past at 120-140 knots and is pretty useless in the last stages of the landing.

Helicopters are an entirely different thing, I seem to recollect the problems that Bristows had with the LN450 on the Bell 212 with the approach to hover. I understand that the manoevre was done manual collective and cyclic inputs following a flight director, while the TR pedals were maintained by the AP. I gather there were particular problems with directional stability when there were light winds and may be a clue why fundamentally helicopters will be such a hard proposition to autoland.

Fixed wing are fundamentally directionally stable especially at typical approach speeds, even an engine failure at 10' agl will not unduly worry a good digital autoland system, however the crosswind limits for an autoland are typically 50-60% of a manual landing limit. Helicopters are not directionally stable at low speeds and the interaction of downwash over the airframe and TR combined with changes in the wind velocity and direction are too difficult to model with any great accuracy.

I would however see no problem in reducing the approach minimums from Cat I to Cat II for helicopters with relative ease, though justifying the cost would be hard when measured by the number of times it was required.

Interested in Nick's thoughts as he would be closer to any attempts in that direction.

[remote hook]

We have autoland on our 212, it' called the co-pilot... mixed results though, depending which system is installed....:eek:

[scottishbeefer]

The chaps at Boscombe have trialled a system to automatically land a helo on the back of a ship (potentially useful in bad wx/nt) - they used a modified Wessex. The a/c comes to the hover, manually or using the FCS in transition down mode. Once established a laser tracks the rotor disc attitude, while a computer takes over the flying controls, and using info from the laser/disc moves the a/c over the deck and lands it. Naturally, this is a grossly simplified explanation.

What could be simpler?! You'd need to be confident in the system to let it land you at night I suggest.

Still only trialled - no in-service date (if ever).

[902Jon]

At Norwich on the S76B we used to fly fully coupled ILS with Decel mode down to 50' (?) and then engage Radalt hold and manually wind it down to the ground. I hasten to add we only did this VFR and with no pax, but it gave you fantastic confidence in the machine and its abilities. The SPZ-7000 would cope with most crosswinds. Also the HOVER mode on the AP was very good even without the optional Doppler input. I remember doing a 45 min heavy hover check (very calm day) following engine chips with the Hover & RADALT modes engaged and the machine didn't move more than 10' in any direction while maintaining heading and height the whole time.

[semirigid rotor]

The EC135 SPIFR will fly a coupled ILS and then level off and fly runway heading at 60ft. You can then reduce the collective to bring the speed back. If you find yourself at 60ft with 65kts on the clock over a brighly lit runway, and you still cannot land; well you really should not have gone flying in the first place :\

[EESDL]

Snag being how th ehlicopter determines its height above landing area.......original post indicates an offset/circling approach where radalt data would not relate to landing area but only on approach.
Airfields where lower cat ILS are flown include all sorts of additional safeguards re protection and undershoot arcs etc.
Autoland to an airport - not such a huge problem, but autoland to an offset/90deg HLS...................pass the whiskey and big cigar co, and turn my baseball cap back to front whilst you're at it!!!