Helicopter Propwash on Runway app's

[SCCM2theFlightDeck!]

Just a thought on something....

I was on final to a short field in a PA28-161 the other day, when the tower controller cleared a heli to cross the runway fairly close to the landing threshold at 90 degs to the r-way direction. The wind was light (abt 5kts) but all crosswind from the right.

Since the controller had cleared the heli from the left to the right handside of the runway (i.e. to the upwind side), I initiated a go around. Whilst conflict with the heli would not have been an issue, I heard recently that the down wash from a heli rotor blade in a cross wind situation can intensify the crosswind to such extremes that what may only be a 5kt x-wind can suddenly be outside the a/c limitations. I think it was in this month's Pilot magazine that some poor Cessna pilot was driven off the runway by a heli down wash x-wind scenario such as the above.

Anyone else been in this situation? :eek:

[QDMQDMQDM]

Helicopters -- nasty, buzzy, whirly, windy things.

Stay clear of the downdraft when you're in a critical phase of flight has to be good advice.

QDM

[The Nr Fairy]

When you consider even an R22 has to chuck half a ton of air downwards to remain airborne in the hover, add in some wind and the downwash will be off on a journey of its own. Big problem for nasty buzzy windy fixed wing things who are confined to running up and down in a straight line to take off . . . :D

It's incumbent on the helicopter pilot to consider this, and on the fixed wing pilot to account for those helicopter pilots who don't. There was a fatal accident at Oxford some years ago, caused by the downwash of an S61 overturning a Warrior on short finals, and a helicopter downwash may have distracted the 172 pilot who crashed at St Mawgan last year.

QDM - if you're even up in my neck of the woods drop me a line and we'll have soooo much fun with our clothes on.

[Genghis the Engineer]

We had an army Helo cut across the threshold of our non-ATZ strip about a year ago just as a Kolb Twinstar was on finals. It got caught in the propwash and the pilot lost control. By some miracle he got it level just before it reached the ground near the far end of the runway (yes, he should have initiated a go-around, the club and the airprox board were all agreed on that point, but none of us were in the aircraft with him for that 10 seconds or so and I wouldn't wish to judge).

So, yes they are dangerous, and yes you did the right thing.

G

[RotorHorn]

Good call SCCM2.

Page six in the "Wake Turbulence" Safety Sense leaflet has a bit about helo's.. and a nice piccy of a Sikorksy S61 showing what you intelligently avoided....download a copy here (http://www.caa.co.uk/docs/224/ssl15.pdf)

[distaff_beancounter]

As I knew the pilot of the Cessna at St Mawgan, I would be very interested to hear anyone else's comments on this incident.

The full AAIB report is here:-
Cessna 182S G-WHDP St Mawgan 23 June 2001 (http://www.aaib.dft.gov.uk/bulletin/jun02/gwhdp.htm)

In particular it is worth printing off the plan that shows the positions of the C182 & the Sea King, at all the relevant times. Then run through it, as if you were the C182 pilot.

The pilot left a widow & two young daughters, all of whom were with him in the aircraft.

R.I.P.

[Fujiflyer]

distaff_beancounter,

I found this accident report particularly distressing to read because of the circumstances in which it took place. It really was one of those cases where to outcome seems so extremely unfair given the prevailing conditions, etc.

Having read the report for the second time it is hard to draw conclusions but from what I have understood the accident seems to have resulted because of poor communications between TWR and the SRG170. The report states that the SRG170 was unaware of the landing Cessna - well that doesn't really sound good enough given the SRG170 was airborne.

The execution of a go around even in the very late stages of the approach, immediately prior to touch down would potentially have placed the aircraft in the path of the Sea King.

So in addition this poor pilot did not even have the option of a go around had he decided he needed to do one without this complication?



I must admit I had not realised that downwash from helicopters was quite so dangerous. And I fly from an airport which is busy with helicopter activity albeit generally smaller ones than the Sea King.

FujiF

[Chocks Wahay]

Not so long ago I took an AA5 into a smallish regional airport. As I was about to flare, a helicopter which was sitting beside the runway lifted into the hover, and the resultant turbulence bounced us down the runway in scary time. Should've gone around from the flare, will do next time. I Learned About Flying From That (as the saying goes)

[QDMQDMQDM]

Yes, it's very hard to delineate an obvious cause from this awful accident report. The only thing I can take away is that when everything looks like it's going pear-shaped you have to devote 1000% more attention to simply flying the aircraft.

QDM

[Wycombe]

Nr Fairy....

The instructor killed in the PA28 accident you refer to Oxford was the same instructor that had sent me on my first solo (at Brize) about 6 months before.

The first (and so far the only) person I've met through flying who has been killed in a flying accident.

It was British Grand Prix Day, the S61 involved was one of those running the shuttles from Oxford into Silverstone.

I was at Silverstone, heard the news of the accident, but not that my ex-instructor had been killed until a few days later - shocked me then and still does now to think of it.

[BlueRobin]

One thing to remember - helicopters generate wake vortex in the same way as any other fixed wing aircraft. I'm not just talkign large commerical airliners either. Sunnysideup will tell you the effect of the AN2 on a light aircraft. :eek:

I believe a Sea King is in the HEAVY wake vortex category