FLI, we have been around this carcass before haven't we mate?
You are right - the excess power has benefits, and if you look closely at my posts I have always said that. I also mentioned the enormous variables surrounding this argument and I like the "meaningless vacuum" simile of Geoff. When talking of the EMS mission hovering over the gorge full of gum trees with two mates on the wire I am purposely giving you a vivid picture of the exposure experienced in that scenario. If you review my post I stressed that given the risk is similar across the three types, exposure is the key to the assessment.
The EMS winch mission gives me far more exposure than the 0.17% typical CAT A passenger ops would. Recently on a BK 117 winch mission in the Blue Mountains I was exposed (with catastrophic consequences) to engine failure for 54% of the mission – not too far off a single actually. But if I was in my shiny new AW139 I would have reduced exposure to almost zero. I like that.
On the other hand, during a recent BK 117 hospital transfer to Nowra, I was not exposed at all to catastrophic consequences, although perhaps exposed to minor damage on landing should I suffer an engine failure in a 1 minute in 100 minute mission. In my shiny new AW 139 I achieve the same, less any probability of even minor damage. BUT – if I could spend even some of the money I saved by flying the BK 117 on WAAS GPS, 4 axis autopilot, IR enhanced vision equipment, synthetic vision equipment, Night Vision Goggles, enhanced pilot to cockpit interface systems, more sim trips to Sweden (how are you Inga?), more emergency training flights, live weather updating service linked from the ground, HUMS, enhanced crashworthy seats,……I think you get the picture. All these benefits have a greater return on the safety dollar than the reduction of the risk of minor damage to almost zero. Dont you think?
Airframes are simply horses for courses and generally, economics determines my horse.
However, the point I am making here is that wherever possible I will be explaining to clients, customers, passengers, and fellow aircrew that dependant upon your exposure level money spent on power is a good thing when going from single to limited CAT A to reduce exposure from 80% plus, to 0.17%. Spending more is past the point of diminishing returns and would be far better spent taming the CFIT monster first. If I am out doing loads of winching during the VFR daylight hours as my primary mission – give me the full CAT A as priority over dollars for HUMS and synthetic vision and autopilot and weather downlinks and….etc.
Unless we talk in terms of exposure, then we will continue to hunt the full CAT A beast whilst being stalked by a far greater threat in the form of CFIT.
I am quite sure that if some of the passengers taking off from the river heliports realised that they will get wet if an engine failed just after rotation they would voice real concern and surprise. They thought that they had bought a Cat A helicopter!
I am equally sure that they will have wished they spent sufficient money on training so that the pilot would operate the CAT A machine correctly so that they didn’t get wet.
Your S76 example hits the nail on the head. Extra power has a penalty and some people don’t accept that penalty for such a marginal increase in exposure. But forcing them into the overpowered machines by continuing the myth that the limited CAT A machine is somehow dangerous or underpowered is why they are going to singles instead. The argument is: if the limited CAT A machine is almost as bad as a single, why would I bother spending so much extra for the twin?
Geoff and Shawn. I agree wholeheartedly with your arguments about the operational and cost issues of continuous operations at max capacities. Well said. Such considerations should be thrown into the bag of variables that the “consultant” needs to consider when advising of aircraft buys – along with operating costs, airframe safety, range, payload, EXPOSURE, reliability, lead times, re-sale, etc, etc. The point we are trying to make is that the full CAT A thing is being weighted in this process far higher than reality requires because of a false perception of it’s penalties versus protection ratio.
Fatty: I thought I baited that hook so well they would be jumping into my boat! Alas, you were the only one and the ranger has asked me to throw you back for breeding purposes.
Eagle86; is anyone be an expert in those things? Or could anyone be an expert in them? Certainly not me, and you know who to call to find out I speak the truth!!!!
