Flying in "dead man's curve" SE

[RotorSwede]

Just wanted to know what you experieced guys think about this subject.

If you fly HEMS here in Sweden you have two engines, two hydsystems, 2 pair of eyes (plus 2 in the back), and you mostly fly in the height/velocity area where an autorotation could be performed. Sure you fly advanced IFR, but you have an experienced captain with you.

If you fly powerlineinspections you go around in a EC120 or Jetranger, with one engine and if the guy spinning the wheels in the back (ie engine) decides to quit for the day, you have very limited possibilities to do anything about it, and below you is a 100% hostile environment consisting of high volt powercables. You are also totallt depending on your own abilty to spot dangers during the flight.

Since I'm in the middle of my ATPL studies I have a very idealised view on the helicopterbusiness now ;) But is it really reasonable to do these kinds of jobs with just one engine ? I think it's very strange, EVEN if "it's the way it always has been", which happens to be the most popular answer to this question.

best regards

RotorSwede

I know it's a matter of cost and so on, but I'm looking for a "deeper" look into all this from ppl that have been around for a while.

[SASless]

In flying I have learned that carelessness and overconfidence are usually far more dangerous than deliberately accepted risks.

— Wilbur Wright in a letter to his father, September 1900

[remote hook]

Rotor,

Flying SE in the "wrong" area of the H/V curve is as SASless says, an accepted risk. When conducting long-line operations, filming, certain types of surveys, you will spend the better part of an 8hr day in there. Obviously one tries to minimize the amount of time spent there, but when doing precision LL work, you my be sitting there for 10-15 minutes.

Engine failures do happen, but not very often, so I'm more concerned about making sure my wind is where I want it, the altitude I'm working at is acceptable for the work/machine I'm doing/using, and the risks associated with the job have been well thought out in advance. When you have a plan, think out possible issues, and prepare for them, you can work quite safely in many situations that are not "normal."

The stoves are good these days, so just try to control the small number of variable I can, and ficus on flying smoothly.

RH

[Shawn Coyle]

Even if there was no HV curve, and the terrain underneath you was hostile (rocky, lots of trees, etc.), the lack of an HV curve wouldn't make the landng any more pleasant.
The HV curve, as presented in the flight manual, is flown (by FAA mandate by the way, not because the manufacturers necessarily want it) to a smooth, flat paved surface. it's one way to reduce the variables, but it means you have to have something up your sleeve if you're operating in an area where you don't have that type of surface in front of you.

[2beers]

Spent 80% of last summers almost 600hrs inside the curve. If you don't have to be there, don't! But if the job at hand requires it, know the limits and the consequences and then concentrate on the job (and wear a helmet). There is always a tradeoff between safety and practicality, if not, then cars would be banned today. You have to decide yourself where the line goes, but it will be difficult to get that multi-crew, multi-engine job without spending some time single-engine, single-pilot inside the shaded area of the H/V-curve. But when doing that, you're usually only risking yourself and that's ok for the authorities...
Hoppas studierna går bra! :ok:
Cheers!
/2beers

[NickLappos]

The balance of safety against probability of occurrence is a tricky one, and when we make it for ourselves, we almost never spend more than absolutely necessary. When we spend someone else's money, the decision gets a bit more theoretical, and easier. There is no demonstrable difference between the safety record of turbine singles and twins when both are operated by the same type of crew. All the interesting discussions about engine failure tolerance and HV curves does not protect a pilot against the cause of 75% of the helo accidents - pilot error.

Question: How many ppruners have turned their old cars in specifically to get anti-lock brakes, 6 station air bags and similar safety features?

[SASless]

Errrr....well....I did Nick....and to zero time the 255,000 mile 14 year old engine, caved in drivers seat, wore out upholstry, and slipping tranny. Got Sat Radio, power seats, and trip computer thrown in as well. The passengers that ride in it....love it over the old one. Being brand new...still smelling nice...I take really good care of it and make sure I don't get any dents in the fender or chips in the paint. Knowing the risk I take if I have a collision....I drive much more carefully as compared to the old one that I would dive off the road onto a muddy track in a hearbeat. No mud getting on this shiny new one thank you!

[rudestuff]

I fly utility patrols in a H269 i.e single engine piston..
It seems much more accepted over here (US) than back home (UK)
where they would probably require a twinstar (twin squirrel) or something.
Single engine IFR is the norm too.
With respect to the HV curve - when you are flying low level all day long you are probably much more likely to hit something than have an engine failure. (and lets face it - a lot of the time engine failures are pilot-induced ie no gas/carb heat/preflight)

[paco]

The only reason you need a twin for power line flying in UK is when you're checking over built up areas. The SWEB unit have been using Twinstars and 206s for over 40-odd years and have only had one accident, and that was only after a flight tester pulled the guts out of the engine. At the levels they fly, you're going to be very close to the ground anyway by the time you recognise an engine failure in a twin.

We had a special low-level engine failure slot in the PPC.

You're more likely to have an inexperienced pilot be blown into wires while in the wrong position downwind than have an engine failure. Then again, the engineers at the SWEB unit are top-notch.

Because of the high inertia blades and its crashworthiness, I think the 206 is the absolute minimum s/e machine to be used on powerlines, especially on those 11kv lines in Wales and Cornwall!

Anyway, the Twinstar is the only twin that is small enough not to annoy the neighbours.

Phil

[TheFlyingSquirrel]

Yeah Sassy, but does the passenger seat go down like the old one ??:p

[rotorfloat]

One of my friends works for a hydro company, and spends most of his days around wires, over wires, under wires. He's stated that, in all reality, any catastrophic failure in those circumstances, "You are toast". And working in the H/V curve? "They might as well put dollar signs in the shaded area of the diagram, cuz that's where the money is..."

[Thomas coupling]

RISK = FREQUENCY X OUTCOME

The chances of an engine failure inside the dead mans curve are negligible compared to the desire to offset that by flying a twin.

[Helipolarbear]

The Deadman's Curve is a technical and somewhat notional consideration.
It is based on pilots reaction to engine failure and it is reduced with a headwind and it's relative W/V......so the variables are many. This in turn reduces the risk exposure of the helicopter if constantly considered by the pilot operating in or near the RFM's H/V charts! The JAA OPS alludes to it by percentage of wind component and distance to attain a certain height above a given obstacle. Try www.jaa.nl for more info!:)

[spencer17]

Deadman's curve is a think you should pay attention to when flying pax or only from a to b.
Deadman's curve in helicopter work like: ag-flying, forestry or construction is something that may exist, but you woldn'd have a realistic chance for a landing without damage if something happens. And don't care if inside or outside the shaded area, underneath your chopper are either trees, rocks powerlines or other things you don't like to land on.
The shaded area is where the money is for pilots, owners and customers.

For my information what is the deadmans curve diagram for Robi's like.
Is it a big gray sheet of paper ?:}

Happy landings
Spencer17

[SASless]

The US Army was very big on teaching the "Dead Man's Curve"....enter Nap of the Earth (NOE) and all of a sudden....DMC fell from the serious discussion to an "Oh by the way...." topic.

[The Nr Fairy]

Spencer:

I know the question was asked in jest, but check http://www.copters.com/pilot/hvcurve.html for a copy of an R22 H/V chart.

[rudestuff]

cant remember what it s for R22, but high hover point for a 269 is 450ft. (ish)
Saw the curve for an MD600 i think - almost double that. I remember being surprised - i had thought the bigger the chopper the smaller the shaded bit..

[SHortshaft]

For many operators the HV envelope is of significant importance when operating Public Transport / Commercial Air Transport Flights.

ICAO Annex 6 Part III, Chapter 3, Para 3.1.2 requires that “Performance Class 3 helicopters shall only be operated…over such routes…that permit a safe force landing to be executed in the event of an engine failure.” This of course includes the arrival and departure phase where the HV envelope becomes critical. How often do you see a Bell 206 or AS 350 punch straight up through the HV envelope when taking off? I would suggest frequently!

It is important, in order to comply with this requirement, to avoid the HV envelope and ensure that the terrain surface is appropriate to a forced landing at all times (as addressed by Shawn Coyle in an earlier post).

Thankfully this is not a requirement for aerial work, where ICAO Annex 6 does not apply. However for some operators it becomes an issue for aerial photography and filming flights which are now being classified as Public Transport / Commercial Air Transport flights by many regulatory authorities. Operating at low speed and at low altitudes on aerial photography and filming flights is frequently “challenging”.

[overpitched]

In Aus one of the groups of pilots that spend the most time inside the "dead mans curve" would be the mustering pilots. And that is done primarily in R22s. You will notice that none of them have commented here and that is because they don't know what you are talking about. Try asking them a question about the "titty graph" and you might geta bit more of a response !!!!

[Banjo]

Just spent over 5 hours in the curve on power line patrol and barely got above 75' (other than the cruise home at 6500' what a great day it was today).

I minimise the risk as much as can and accept those I think are worth taking on board. We all got to go sometime and though I hope it is when I am ninety and in bed with two fine young ladies ( I believe they call it Coronary Orgasmosis when one Cums and goes at the same time) at least if I go in a crash it will be doing what I love best, oh and probably also my fault as nine times out of ten it is the monkey on the stick who makes the error.

As Paco says at our heights and speeds if the engine stops in a twin the second one is probably not going to stop the sink in time and especially not when in amongst the towers. By the way Phil bet your not missing those welsh valleys much, hows the sun out there.

[SASless]

Banjo,

Now that would be an accident investigation...a 90 year old pilot and two youngish females, a mangled cockpit....the forensics people would have a fit trying to sort out who was driving!:E

[paco]

It's nice and warm, and I've only seen 33 Kv lines here! The 212 is a real pussycat - and they pay me!

I found with the 206 that we could maintain 35 kts on the 33 lines, but once you start with the twisty-turny stuff on the 11s, and the poles go by every three seconds, you had to be very careful to keep the speed on. I know our Ops Inspector had no idea of the problems iuntil I took him on a trip. A good powerline pilot is like an advanced motorist - the hands and feet are in the right position before you get into the corner!

I still think some of those Welsh valleys are twin country - I remember pulling a trip once in the 206.

How's the new hangar?

Phil

[Heli Sport]

Overpitched, was waiting for someone to mention the Oz mustering pilot as it is common for the senior pilots to do there 1000-1400Hr limit in a season of which 80-90% would be low level and inside the HV Curve and mainly in the R22 with some H300's about (few and far between). You have to be aware of absolutely everything around you in this environment, including thinking about your wind, cattle, other helicopters, groundcrew, fuel,Ts&Ps, your surrounding around you eg, trees,powerlines, birds and all the other nastys.Trying to maintain your airspeed as much as you can is one of the most important factors I believe as well as always planning yourself escape routes before you go into every situation as these things combined will help to minimise risks. If something does go wrong you can only try to put yourself in the best situation possible. All this was taught to me when starting off in mustering by high hour pilots and it still stays in the back of my mind in every situation I go into.
It's unfortunate that some rogue mustering pilots stereotype the whole mustering industry into "cowboy pilots". That's why I believe you see alot of mustering pilots getting out of the industry after 2-3yrs as they don't want to be labelled with this cowboy pilot image by the rest of the aviation world!
I do believe a mustering pilot with the same amount of hours as a tourist or charter pilot is miles ahead skills wise when it comes to handling and flying a machine maybe not flying a textbook circuit or doing the best radio calls but actually flying the helicopter. Anyone else with comments on this?
Anyway getting pretty sick of the wet season at the moment and just about ready to get into another season in the next month or so :ok:

[Two's in]

UK Army bent most of their Gazelles by throwing them at the ground to teach people what happened when the donkey stoppped - trouble being, the donkey hardly ever stopped (single digit occurences in 30 years of Ops, despite mostly being less than 100' AGL all your life) so the accident stats for single engined ops were completey skewed by training for the event that never happened. To balance the down side of all the engine off training, at least you always knew you could get it on the ground safely "sans moteur", a far more likely occurence when you migrated to the twin engined fury of the mighty Westland oil slick (Lynx). Now there's an aircraft where you really want to know where the the avoid curve is.