EMS Very Slow approach - why?
 

I was just curious why every EMS helicopter I've seen seems to slow to almost HOGE and do a really slow, increasingly steep "parabolic" approach. It's stable, controlled and looks safe, but I was just wondering if maybe someone could describe in detail what that approach is all about.

I've wanted to re-create that kind of approach in training, but the instructors I've had bark when I get slower than 30 kts if not within 30' of the ground (which feels way faster than "walking it in").

I'm of the opinion (because people argue this all the time) that you can't stabilize anything steeper than 30kts 300 fpm without slowing down first

- or using a "skijump approach" (30kt/300+fpm - flare 30/0 to 0/0 and descend pretty much IGE).

I just don't get it.
Keep in mind this is a question, not a statement.

It gets you slow....gets the power in....gives you lots of time to look for wires, obstacles, and if landing to a roof top allows you to get to the deck if an engine quits.....or so it was explained to me years ago by an Operator i worked for.

I saw it as prolonging the agony if something were to go wrong.

I do agree with a steep approach but with a normal rate of descent rather than the very low ROD as is used by some of the Operators.

Multi-engine helicopter or single engine?

Even with a single engine machine it is a generally safer approach (especially at night) when landing to unimproved areas. Your chances off hitting a wire or other nearly invisible obstacle are much greater than your chances of having an engine failure. Power should not be of any issue since you are planning to to pick up 200 pounds or so and accomplish a nearly verticle take-off if it is a scene response. Less than 30/300 should keep you clear of settling. You have nearly hover power applied and a very slow descent so if you see something you don't like, a go-around can be accomplished with nearly ZERO further descent or delay. You will be above any dust/snow cloud so you will not be surprised below the barriers, and will have the option of continuing the approach, stopping to a hover to see if the obscuration dissipates, or go-around and plan a new course of action.
Not being in a hurry is usually to your benefit.

Mmmm ....

AND I really think you'll find that the 'parabolic approach' isn't that at all ... but a well defined constant angle varying airspeed low(ish) rate of descent requiring minimum power changes till committing to the hover ...

Sometimes you might even have a crew member with their heads out the door checking and clearing your tail ... the communications for which will require time ... you don't want to be doing that stuff in a hurry ... THAT IS how incidents can occur ..

:ooh:

Sounds exactly like a Class 1 heli-pad approach as specified in the AFM.

I fly the 135 and our ops manual says that ALL approaches to confined areas shall be flown to the Class 1 profile (EC135 LDP 120' IAS 30kt ROD less than 400' per min) In the event of an engine failure after LDP the landing even at RTOW is assured. The take off is basically the same thing in reverse (TDP 120 ft, ROC 200-300' FPM keeping the landing area in sight at all times)

I can understand why your instructors bark when you try it, if your'e in a single engine aircraft it will stick you (and the long suffering instructor) right in the avoid curve, while a lot of utility pilots spend a lot of time in the avoid curve many instructors are a tad concerned at being in the curve with a low hours student in control, an engine failure there will pretty much guarantee a broken helicopter and occupants.

VH

We run a 135 as well on a yacht, moving platform most of the time, and all our approaches and departures are Class 1. Our pad is the minimum dimensions the designer could get away with (but fully rated - never have worked that one out!!) and plus we normally have turbulence from the accommodation and heat from generator engine exhausts to contend with.

As a side bar I saw an EMS 135 in Devon a few years try to land in a field next to a car & motorcycle accident and he had to bail out as it was too steep, and then only place left to land was on the road in a very tight area with cables and trees all around him, weather was very severe almost gale conditions, he tracked down the road towards us, down a hill, with tail into wind and slashing rain, plonked it right in front of me. The best bit of flying I ever seen!! In from high and fast with a fancy flare was never going to work that day!!

I try to guard against the most likely bad occurrence. At an airport or prepared heliport, where I'm sure there are no wires, I do a faster approach, but to an unprepared scene, where the likelihood of unseen wires is greater than the likelihood of an engine failure, I make a very slow approach, at least for the final couple of hundred feet. There are wires everywhere, and they can be almost impossible to see until you're within a few feet of them. Making the approach slow enough to allow stopping to a hover, and then climbing back out, gives me the best chance to avoid wires. I don't like vertical takeoffs, but doing one from a scene is safer, IMO, than trolling for wires on a normal takeoff. Playing the odds gives me the best chance of surviving and making another flight, and the odds favor slow, steep approaches and vertical takeoffs from unprepared scenes. From a runway, obviously a normal takeoff staying outside the avoid area of the h/v diagram is safer, and that's what I use when I can. It all depends on the situation.

The Survey says.....
 

to avoid settling-with-power.

I asked a BK117 HEMS pilot that question years ago and his answer was he wanted to avoid settling-with-power.

At night doing takeoffs from Scenes....I pointed the Landig Light, Search light, and Night Sun up nearly vertical and flew up the light beam to make sure I did not run into any wires. The risk of an engine failure was far less than that posed by a wire strike.

Likewise at night I made steep, slow approaches using the lights in the same manner but pointed downwards and tried to stay along where the lights were shining.

That was in the Bell 412/BK-117/BO-105....so we had plenty of power and lots of light.

I would not do EMS flying at Night in a single.....there are plenty of jobs available so one does not have to do that. (Personal Opinion thought it is!)

Doesn't anyone recce the LS in an orbit or from the downwind leg at low level to check for wires and things any more? Looking at the site from more than one angle gives you far more opportunity to see those hidden wires and select the best point to make the approach to.

This is how we tend to do it at night as well.

Lots of things can surprise you on final after a few turns around the LZ reconnoitering your heart out. I am sure you have never had a surprise at 2AM. Set yourself up for success and with luck you will never have to use your back-up plans.

Of course we do low recons of the LZ. But I never, ever bet my life on being able to see every wire from a few hundred feet up, while moving at >70mph. Powerlines and telephone lines can be very small, and difficult to see while standing directly under them. I know the firefighters on the ground have looked for wires, but they can miss them, and do. Making a couple of circles and then a normal approach, assuming you've seen every possible wire, will kill you eventually.

Crab,

I have as strong a desire to live as the next guy....and did my utmost to avoid a premature departure for where ever I am bound when I do....but I have had some very close calls.

Put the wooden poles back inside the wood line....stretch a wire or wires between them over a roadway....and see how easy it is to miss seeing them at night....even with all sorts of lights shining down on them and Fire Fighters doing a ground Recce for you to boot.

Put a nice skinny radio mast up near a hospital landing pad.....and not put any markers or lights on the guy wires.....see how quickly they disappear.

I have almost run over wires in the day light drying Cherry Trees....which is nothing more than a low forward speed HOGE exercise. Some of the wires are damn thin and skinny.

Every one does a good Recon at night....sometimes it is three orbits around the LZ or more even.....No sane person does a single downwind oogle of site and then does the confirmation on finals....and lives to be an old man anyway.

I am with SAS... Wires are difficult to see. In order to fly for PG&E and WAPA, all of my pilots are required to complete annual training on "Flying in the wire environment". The initial course is TWO full days...... Before attending, I thought the same as most---how do you fill 2 days on wires....? I now do the annual one day refresher every 12 months and still learn new stuff on how to detect wires.

If you have not seen it, this is worth a watch:

You all have been absolutely ..... AWESOME!!!!
Thank you very much for the participation, the thoughts and most importantly taking the time to discuss this so that I (And I'm sure a lot of new or young pilots) can think, discuss and most importantly LEARN from your experiences.

I know it sounds a little .... I don't know .... wierd, but the stuff I read on these boards are sometimes the voices in my head when I'm approaching questionable situations.

Thank you guys very much.:ok:

You make a really good point spinwing - I've never actually tracked one all the way down, my imagination actually kind of filled in the vague spots so I can tell you definitely .... that I wasn't quite positive it was "parabolic".

BTW - how come the firefighters don't hose down dusty LZ's? (or do they?)

Runon

We do:

I didn't say stop looking for wires on final approach but you don't have to make slow, steep approaches to avoid wires - certainly those of you who have operated in a tactical environment won't have done that.

I cut my professional teeth in Northern Ireland where every field has wires but we still managed to get in and out quickly without taking any out, day or night.

The suggestion that you have to do a very steep and slow approach to be safe is erroneous and misleading.

Yes there are always the telephone wires in the tree-line and the little whip mast hiding but a low-level recce at relatively low speed and height plus vigilance on finals (if you have picked the clearest approach path) will keep you safe 99% of the time.

There will always be the really tricky LS where there are so may obstructions and such a small area to land that a high hover and vertical or steep approach will be required but there is no need to use this in every case as some people here seem to be suggesting.

Gordy

I would pull that video link if I were you. You missed him - he hid behind the truck!

Crab,

This ain't Northern Ireland, and with very rare exceptions there are no bad guys shooting at us, and we have said the high, steep, slow approach is the better technique for avoiding wires... not the only way. In most cases using the Steep/Slow approach will allow you to see the Wires you might miss on a standard Confined Area Approach in time and avoid them. The Normal Approach you mention sounds good in theory but in reality there is a better way. That is the point being made....and most have accepted that.

In essence what you just told us is you prefer to cling to the standard night LZ approach and landing technique you learned at the Colored Pencil Academy no matter the circumstances.

Do you only wear one pair of shoes?

John R81

We got this one though..... ;) ;) :cool: :cool:

Runon, sometimes they do hose down the LZ, sometimes they don't. It's hit or miss. In the area I fly, there is exactly one full-time professional fire department. The rest are volunteer, unpaid, part-timers with minimum training, doing it in their spare time to help the community, and we don't hassle them. We take what we get.

Crab, you seem to have never flown in a forested area, where the roads are lined with trees, trees are everywhere, and the power poles are mostly hidden in the trees. I recently landed in the middle of a major interstate highway for a wreck, and since the scene was near our base, we arrived before the fire department had a chance to set up an LZ and stop all the traffic, so we circled for some time while waiting. We had plenty of time to recon everything, and thought we saw a place where wires crossed the highway, but we couldn't be certain. We checked thoroughly, but couldn't see any wires. This was in broad daylight, mid-day. On final approach, we finally found the wires, the poles hidden in trees on each side of the highway, just one pair of wires in front of us. A normal fast approach would have resulted in our being in the middle of the highway with rotor blades and parts spread all over the place. You fly approaches your way over there, and I'll fly them my way here. I intend to retire alive.

Crab.
How many wirestrikes on approach do you know of. I know of at least a quite a few. Many were fatal. How many engine failures on approach do you know of, I can think of 2 and neither was fatal. Choose your exposure.

The whole problem, and I dare say the reason we keep having these accidents is people like you that think they will be able to see wires on a full speed confined or semi-confined approach.

Watch the video again.

Crab
If you ever leave the RAF you will learn how to fly Class 1 approaches. If you lose an engine close to the ground it may well save your life.

That water drop getting the girls .... um "watered". Brings so many bad one liners to mind.
Cheers to you Gordy - those gave me a good laugh.

I hear you Gomer - I used to volunteer and really we weren't supposed to do anything unless we were told specifically to (you know how they are with rookies).

I am surprised someone especially Sasless, hasn't supplied Runon with the real answer.

Of course they will go slow where there is a good chance of a crowd there to watch, it's when they are out in the boonies that they go real fast straight into a cloud full of rocks or whatever to make a real splash on the next days newspaper.

It is the American EMS you are asking about I presume? :ugh:

So let me get this right - you guys are advocating a slow steep approach into every LS, no matter how unsuitable the floor might be for a Cat 1 engine failure after CDP landing (the slope and surface are often difficult to asses until in the hover) or how long you might spend in the H-V curve (in a single)?

Unless your LS is very small (which would necessitate a confined area approach) why not aim deeper into the LS in the knowledge that you will therefore be higher over the LS boundary (where the wires are most likely to be hidden) and are less likely to encounter tiny telephone wires (which will snap before they take out a helicopter) which are the most likely ones to surprise you.

Maybe you just don't have power lines marked on maps in countries where you operate but we do, right down to the 11KvA small lines on wooden poles (that will trap a helicopter) so for us, a decent map and a good recce, plus the abilkity to modify how we approach into the fields means we are not stuck in the - 'one size fits all and it's the only safe way to do it' slow, steep approach that seems to be the favourite of most here.

Sasless - I think I am the one advocating flexibility of thought and action - I can vary my approach to suit the conditions.

Gomer - no, we just don't have trees in UK:ugh::ugh:

500 guy no, people keep having these accidents because they are not looking for wires adequately - I am happy that I can do that from a low level recce and confirm it on finals without having to fly ridiculously slow and steep. My choice of exposure has kept me safe for over 30 years in some quite demanding circumstances.

If you think every single wire shows up on a map somewhere accessible to the everyday pilot.....you are in serious need of a drug test. That statement ranks up there with something like The Sultan might say.

Wrap them puppies around your P/C Links......and see what happens.


As to flying near Trees....despite there being some trees in the UK....we have wood lots bigger than some of your forests.....out west where logging still goes on.....Wires can crop up within hours.....so the valley you just flew up might not be as safe as you think on the way back home.

Single or Twin....engine failures are so far down the risk scale compared to wire strikes...particularly in degree of outcome.....they just don't matter and you know it.

As the conventional wisdom proves.....Wires can be anywhere Crab....and that means even right up there at the far end of your LZ.....that is the point Mate....one never knows.

You just keep doing your normal approaches using the school solution and allow the rest of us to do what we see as best meeting our needs.

Germany wire strike since your talking wires
 

One dead in German helicopter crash on highway

Associated Press | Updated: January 10, 2013 23:31 IST


Berlin: A helicopter crashed on a highway in southwestern Germany on Thursday, killing the pilot, after the aircraft got caught in high-voltage power lines and exploded, police said.

Pieces of the helicopter hit a truck near the town of Schwaebisch Hall but the driver was only slightly injured. Police said they believe the pilot was alone on board.

The highway was closed in both directions following the accident, creating a major traffic jam.

German news agency DPA said the helicopter belonged to a private company in the region

"Of course they will go slow where there is a good chance of a crowd there to watch"

LOL - HAHHAHAAA:D

Mmmmm ...

...... to encounter tiny telephone wires (which will snap before they take out a helicopter) ....

Crab old darling .... have you ever inspected any of those 'tiny telephone wires' close up?

During one of my 'vacations' from aviation I did in fact do a 5 year stint as a 'Telecoms tech' and spent quite some time re stringing and repairing aerial telephone lines ....

With the smallest copper aerial cable (what we call a 'one pair aerial') ... the 'tiny wires' you speak of are indeed tiny the phone conductors are a pair copper wires of 1.5mm cross sectional area and are in themselves not that strong ... BUT an aerial cable is supported by a 'catenary' wire which is made of tough steel 1/8th of an inch diameter to allow support without excessive sag between the support poles ... this IS tough stuff believe me ... if you don't strike the cable run with the appropriate 'wire protection device' on your machine before you know it, it will have wrapped itself around your pitch links or tail rotor and caused a serious loss of control before it reaches its breaking strain ... and that is just the small stuff!!

Really you don't want to go there ... and while the military tactical decision might validate such a risk ... the civilian one will not ... standard of thought should be "when there is any doubt DON'T do it".

Cheers

Crab-
My employer requires the slow vertical in and a vertical out of an unimproved landing site, period. It is a compromised technique in some scenarios, but it's what I am to do.

This steep EMS approach being discussed, what kind of downward visibility does it give you of the landing site?

The downward visibility depends on the model, of course. If there is a chin bubble, the visibility is excellent. Without one, it's not so good. Everything is a compromise of some sort, so the approach angle and speed has to be balanced with the ability to see where you're going. The less you can see, the slower you need to be. In the model I fly, you can see almost, but not quite, vertically, up to ~70 degrees down. I don't often get completely vertical, but sometimes it's necessary for the last 50-100 feet, depending on the obstables and LZ size.

Mmmm ...

Remembering of course one has the option at slow(ish) speeds to put in a bit of left boot (or right as the case may be) to cock the a/c around if necessary to improve the downwards visibility ... needed perhaps with the 139, S76, B222 etc .....

Thanks for the replies. :ok:

Please forgive me if this is a very stupid question but - are wires hot? If so would it be possible to affix a small (less expensive) IR camera to the helicopter to assist in checking for wires.

If so then could there be a small flir ball beneath the aircraft that runs a pre-programmed sweep once you push a button in the cockpit and which covers the whole area beneath the helicopter and shows the pilot where the wires are?

SASless, Spot on.

Crab, any unimproved LZ yes. same class 1 approach.

No map has 100% of wires. Telegrapgh lines will and have taken down helicopters. So have logging line and other "lines" that are temporary and would not be on your map. Powerlines are not typicaly hot, but can be under intense loads. The infrared thing would not work on denergized lines, telegraph/telephone lines, guy wires, loging lines etc. Anything that only works 95% of the time gives a false sense of security and actually detracts from safety, thats why every catalog based wire detection system or map has failed.

OK, lets pretend we are only dealing with telephone wires since anything bigger is likely to be less hidden and possibly (in a civilised country ;)) be marked on a map. There is no real excuse for hitting HT cables (but it clearly still gets done) and those are not the type of wires to be hidden in a treeline on approach to an LS.

The average height of a telephone wire in UK (at least) is about 20 feet so in order to get it wrapped around your rotor head you will have to be very low indeed (even I don't come in that low!).

I do know that copper wire is strong but the only time I know it has been a problem is when a Lynx collected about 2 KM of the stuff from a TOW missile around the MRH after flying along a valley where there had been a firing exercise. That did not bring down the helicopter and is a massive amount more than the few feet of it you are likely to collect from between telephone poles.

I can understand the imposed limitation of flying a class 1 approach from the standpoint of fare-paying passengers and air transport work - it is the legislation after all. But, if you are not employed in that sphere, it is surely better to be flexible in the style of approach - coming in steep still does not guarantee that you will see a small wire.