Downwind landings (and take offs)

[TheGreenGoblin]

I had my first go at downwind landings and takeoffs after a long brief yesterday. The weather was very blustery (gusting at 30 knots at times) so it was an interesting and at times (for me at least) quite demanding exercise, in the case of the downwind landing, as there was always a sense that one could lose tail rotor authority in the gusting tail wind, but in fact the R44 was remarkably docile and controllable. The caveat from the outset was, this is not a license to ignore the presiding orthodoxy and good sense of into wind take offs and landings, but an advanced lesson allowing the assessment of all factors, such as weight, available power etc. and the amount of risk and likely success of a downwind take off or landing attempt, where no other more conventional, and safer, technique is available due to factors such a topography, obstacles etc. My instructor noted that the majority of downwind mishaps occurred where the pilot became spatially unaware and lost the sense of the wind direction as in this case https://assets.publishing.service.gov.u ... _11-20.pdf or simply ignored the wind direction.

On the take off side of things it was relatively easy to see the movement of the grass and boundary of the effect the rotor downwash and to see that boundary between agitated and still grass coming closer and closer to the front of aircraft as it accelerated towards the point where translational lift became effective. One can literally feel that point in the R44, where it starts benefitting from translational lift, as it gives the slightest little shrug or judder and then comes alive and is joy to fly thereafter and climb away, at an air speed of about 35 knots yesterday, in pursuit of the normal 60 knot ascent speed (albeit closer to the boundary fence than was usual as a result of the following wind) .

The downwind landings were even more interesting while attempting to initiate a longer flatter approach, minimizing the descent rate, always being conscious of the higher ground speed, and the need to avoid letting the aircraft get into the vortex ring region, while not overpitching, being aware of the power available, in one's impatience to bring the aircraft to a hover and, if need be, doing a run on landing.

Back home I have been doing some reading on all this and found this article very interesting.

I hope the cognoscenti here will humour me in my enthusiasm and tendency to state the "bleeding obvious" or simply getting it wrong. I would be most interested to hear other people's comments on this subject.

https://blog.aopa.org/aopa/2015/03/25/d ... -involved/

[CharlieOneSix]

A good handling and control exercise with IMHO little practical application. A well written AOPA article and I liked the comment "If you do this bring your tap shoes because you will be dancing on the pedals". It's a loong time since my basic training but I can't remember much time spent deliberately doing things downwind apart from downwind fast stops where you approach downwind with airspeed and fling the beast into wind and the hover with a steep turn and flare.

I remember one occasion during basic flying training when my poor instructor on piston Whirlwinds was trying to get my lame downwind fast stop attempts to meet his expectations. I was being too cautious and gentle but he wanted me to give it more welly. So I did and somehow we ended up into wind, nose high, RRPM anywhere but where they should be (no governors!) and hurtling backwards. The expletives that came from Bill Berry's mouth as he grabbed the controls to stop us stoofing in tail first were memorable!

[TheGreenGoblin]

"If you do this bring your tap shoes because you will be dancing on the pedals".

Methinks this was the point of the exercise in my case!

I appreciate your comment and insight C16.

[FD2]

Well done GG - I bet you were sweating after that! No one will criticise enthusiasm and it's good to hear the lessons are progressing to difficult handling flights like this.

Some people just test their luck too far:

[TheGreenGoblin]

Well done GG - I bet you were sweating after that! No one will criticise enthusiasm and it's good to hear the lessons are progressing to difficult handling flights like this.

Some people just test their luck too far:

Thanks FD2.


Ouch, that video seems to indicate a gusting tail wind. Very luck that nobody was hurt.

[Boac]

What on earth made it leap so violently into the air? Did they not go to negative collective?

[CharlieOneSix]

The Aviation Safety Network summation says a gust of wind from behind was the cause. Seems it got the pilot before he/her had fully lowered the collective…..
https://aviation-safety.net/wikibase/182668

[Boac]

I'm still surprised by the speed of the 'leap'! Would you say that was typical of a tailwind gust? What are the 'mechanics' that make one of those do that AND tip the hicolepter its nose?

[TheGreenGoblin]

The aircraft was comprehensively broken!

[Boac]

I think we should wait until the investigation.................

[TheGreenGoblin]

I think we should wait until the investigation.................

I await the prerequisite METAR!

[CharlieOneSix]

Regardless of anything else it was good airmanship to land as he did so that the natural egress of the passengers was away from the tail rotor. I find it difficult to believe a tailwind gust caused that. Three up in the front seats so quite tight. Cyclic tending to the rear in the hover to counteract the tailwind. Pilot moves the cyclic towards neutral as he touches down, still light on the skids with a bit of collective still applied although on its way down. At the same time an eager passenger somehow hooks his camera case strap around part of the collective and pulls....it wouldn't be the first time.

[Boac]

Sounds very likely, C16.

[G~Man]

I find it difficult to believe a tailwind gust caused that.

I do not think it had anything to do with the wind, but more likely pilot over controlling. There were 7 people on board, hence the CG was pretty far aft, giving it a nose low attitude. Astars typically touch down on the spring plates at the back of the skids first, (nose high), then as you lower collective the rest of the skids make contact.

Look at the video again, he touches down on the toe of the skids and as he lowers the collective the aircraft rotates backwards, and right as the back of the skids touch is when the aircraft lurches forwards. I suspect the pilot was suffering from somotographic illusion and maybe though the aircraft was rolling off the back of the pad and over corrected. Just my $0.02

[FD2]

If there is a slope down to the beach behind the pad it's possible an updraught lifted the stabiliser, at the same time as the gust from behind caught it. Forward c of g may not have helped.

[Boac]

Phew - and without a METAR too.