CSAR and Chinook rotor downwash

Rotor & Wing columnist Giovanni di Briganti argues this week the CH-47 is “unsuited for the combat search and rescue mission”, citing the Oxford coroner’s report in October that blamed the Chinook’s downwash for indirectly killing a paratrooper waiting to be rescued in a minefield. An excerpt:


In this instance, the downwash from an RAF Chinook attempting toland dislodged rocks which, in turn, detonated other mines. One of themkilled Cpl Wright.

The second failing is that the Chinook had to land because it wasnot fitted with a rescue hoist, and so could not pull out the injuredsoldiers while hovering.

The third failing is that no other available British helicopter wasfitted with a rescue hoist. The British forces’ shortfall in helicoptersupport is well-documented, but it is in instances such as this thatthe full consequences of that shortfall are felt.

I’ve been on the receiving end of the Chinook’s downwash a few times, and I can vouch for its power. Of course, one might question whether the downwash from any of the CH-47′s competitors would have produced the same result in that situation. The real problem may have been this particular Chinook’s lack of a hoist — and not the rotor downwash.

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4 Responses to CSAR and Chinook rotor downwash

  1. sferrin 5 December, 2008 at 6:14 pm #

    If down wash is such a problem just give it a longer wire. Sheesh, is it really that tough of a problem?

  2. Matt 5 December, 2008 at 6:33 pm #

    All I know about the rescue mission is what I saw in an IMAX film about Red Flag. From the film it seems that for USAF rescue missions, the choppers land and pat the guy down first before letting the stranded board the helicopter, to make sure that it’s not an enemy in costume.

    Is this still the procedure (the film was a few years old I’m sure)? Do current CSAR missions routinely use a harness as opposed to landing/patting down?

  3. airplanejim 5 December, 2008 at 6:47 pm #

    Giovanni is a little short in his analysis of the problem. Rotor wash of the Chinook is substantial but would rotor wash from any rotocraft have done the same thing? The real problem is the RAF’s lack of a hoist. Okay Giovanni who are you pimping for?

  4. Starviking 6 December, 2008 at 3:19 pm #

    The problem with a longer wire is that it will increase the wind-down and wind-up times, so increasing time over target.

    It will also mean that the horizontal motion of the end of the wire will be greater – making it harder for the person on the ground to grab the hoist loop (sorry, the technical term escapes me at the moment). If a crew member is descending to aid the person on the ground in their ascent, then that member will be at greater risk of injury from getting slammed into ground obstructions.

    As an aside – how bad will downwash be from a CH-47 near the top of the hoist?

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