I am looking for bell 412 pilots who could explain me the exact approach speeds during a landing?

Question

There are 2 school of thoughts

1. Maintai 45 kts till 200 ft and then gently bleed off speed and height to a landing.

2. Maintain 45 kts till sure of getting in to the landing pad (close enough for the momentum to carry u through) and then bleed off spd- this has an option of going around (in case of an OEI)

which one is right?

Answer 1

I'm not a 412 pilot but I've ridden through a grunch of landings in jungle and offshore locations.  To my knowledge approach is governed by terrain, LZ and weather conditions.  In the old Post-Nam days you could also include pilot exuberance.  

212's and later 412's made up the bulk of oil field support.  In fact in the early 80's in Indonesia I rode in one of the first two modified.  I think it was chartered by a company called Dezarona.  It won't google so maybe they are defunct now but those were the days.  There were a lot of Nam vets that stayed in Asia and were fun too fly with.  

I got off the point but I did find a site that may help you find your answer, http://www.vectorsite.net/avhuey.html

Good Luck!

Answer 2

Depends on the LZ size and obstructions. For very confined area operations, I bring the helicopter to an OGE Hover above 300 feet AGL, do a power check then do the approach at near zero airspeed from 300 feet to touchdown at less than 300 feet per minute.

For a normal approach to an open area, I slow the aircraft to about 60Kts on final, then use visual cues to approach the LZ at what looks like a fast walk. The speed throughout the approach is constantly changing and it is zero when over the LZ at a 5' hover.

Most helicopter approaches are flown similarly and there are no "exact" approach speeds. When you consider pitot/static errors that may occur if the aircraft is not perfectly streamlined, the speeds are not as important as the visual cues.

On twin engine helicopters, if one engine fails you may be able to go around but it depends on the altitude.

For example, a BO105 will be able to go around after losing one engine when from hovering OGE above 150' agl. Pilot technique also have a lot to do with the successful outcome of an engine failure.

Answer 3

I have never flown a 412 (unfortunately), but I'll give my perspective.

I have also never flown a multi-engine, so I am not sure of all the OEI performance considerations because for me, OEI = autorotation so it's a different perspective.

I guess the argument for keeping your airspeed up in the event of OEI would be to prevent excessive altitude loss or overtorquing close to the ground/LZ. However, it depends on the LZ. If you are landing on a runway, then you have plenty of space to lose the extra speed at the bottom. If you are landing on an oil platform, you would have to be almost on top of the pad before the landing is assured. I think it would be hard to decelerate from 45 kts in such a short distance in such a large aircraft without having to do a radical maneuver. On the other hand you don't want to be too slow and lose an engine and drop down suddenly just in time to collide with the side of the platform. It all depends on the situation.

I guess if it was a platform, you could do a slower steep approach so that if you did lose an engine, you could either land on the pad, or go past the pad where you would get "free" altitude. If it is a runway type of environment, then it almost doesn't matter because you have so much room to work with. If it is a confined area, it likewise doesn't matter because you will inevitably have to spend at least a little time in that "death curve" where an engine failure would just suck. There is no way around that.

I don't really use the airspeed indicator once I am established on final approach. 45 KIAS with no wind is different than 45 KIAS with gusty winds. 45 kts to a big flat open field is different than 45 kts when descending into a small area surrounded by obstacles, or a pinnacle on top of a platform. 200 ft will also occur at a different point depending on how steep your approach angle needs to be. I use visual cues to judge the descent rate and rate of closure and adjust control inputs accordingly.

In short, I am not sure there is a one size fits all answer for approach airspeeds in any helicopter. Each situation is different, and there are so many factors to consider. I think you just have to decide which factors are most critical in any given situation and make the best choice for those factors, knowing that you will make a sacrifice for the lesser factors in that case.

That's just my take though, based on limited experience. I recommend the following sites, as they both have forums where you can ask pilots with more and varied experience.

http://www.verticalreference.com/

http://www.justhelicopters.com/topics/ca...