Moggy’s Tunaboat Helicopter Manual Ch.3-B “Wind, waves, and wild decks “

Posted on July 17, 2009


Landing on the Chi Tai 866, 30th January 1998

PART 3 “Moggy’s Tuna Manual ” “Handling your helicopter “

Chapter 3-B Wind, waves, and wild decks

Few things can compare
with this crazy dare;
if you crave the ultimate trip
go land, my friend, on a ship,
on a wild and stormy deck
rolling around like heck.

Now that we have talked about ‘LDP’, and the ‘relative wind’ and now that we have suggested that ‘sliding down from the sky’ (300 to 500 feet per minute rate of descent) with a relatively low power setting is better than ‘high hovering out of ground effect, horizontally with a lot of power’ , let’s slowly build up the picture for you of some very common tuna helicopter accident scenarios.
I’m betting at this stage that some experienced tuna helicopter pilots reading this, already know exactly where I’m going with this. Some of these guys, whose participation in this discussion I really welcome, would be just as able to write this chapter as I am…! These guys, like myself, have probably seen this type of accident occur. For the new tuna pilot, and especially the 200 hour new guy, I will try to the best of my abilities to spell it all out slowly.

Okay, the effect of wind. Any pilot will welcome some sort of headwind component as he comes in for landing. The stronger the headwind on final approach, the closer your LDP will be -horizontally- to the helideck. A nice strong wind will please an experienced Bell 47 or Robinson Rotorhead. He can keep translational lift nearly all the way down, so his reserves go up! Anyway,it’s fun.
A nice strong wind that pleases the experienced ‘Tunahead’ helicopter pilot may not please a nervous newcomer, a “anchovy head “, because the strong wind will almost certainly whip up some merry waves. Now the deck is pitching, rolling and maybe heaving fifteen or twenty feet up and down, all at the same time. (If these terms confuse you, just think of an airplane; the nose (bow) of the ship pitches up and down, and the ship rolls from side to side. ‘Heave’ is when the whole ship, not just the bow, rides up on the swell. It is often associated with quite a pronounced,juddering ‘smack‘ as the ship rides down, and an impressive bow wave plus a lot of spray.

Now. Helicopter accidents are often not the result of a situation you have never been in before. Helicopter accidents are often the result of ending up in a situation in which you have been hundreds and hundreds of times before. Without a problem. Then, along comes a very small difference. If you fail to recognize that subtle difference, that concealed threat, that is when you can get hurt. Remember the accident/safety poster I talked about?

“Been there, done that,
Been there, done that
Been there…. (yawn, bored)
Been there……………OOPS!! “

STAGE ONE:
When you first start out, you tend to approach a pitching,rolling, heaving helideck SLOWER than normal, and SHALLOWER than normal. It’s understandable. This means you are pulling more power, you’ve got less in reserve, you’re less well placed to cope with problems. You’ve got less ‘spare height’ (height in reserve) to deal with engine failures, or go arounds. Agreed? You are entitled to disagree!
(If you do disagree, then you will disagree with the next section as well)

STAGE TWO:
This slower, more shallow, more cautious approach may be no bad thing in a way, but after you have built up some confidence, I suggest you will discover that a pitching, rolling, heaving helideck (even with impressive bow waves and lots of spray blowing around) after a while… doesn’t make a whole lot of difference! Your confidence is building, and that’s good, but a hidden gremlin is still waiting for you.
I have really tried to study what I do instinctively now. My approach angle is just as steep. I have a positive rate of descent. (I’m not high hovering out of ground effect with a lot of power). I come down quite rapidly and positively, no messing about, and at the very last stage I maybe pull in a little more power, and cross the deck edge of the helideck a little slower and more cautiously, but that’s about it! My rotordisc/deck edge overlap time (DECT) is maybe a little bit longer, but ‘not a lot’. The actual touchdown is quite positive, no messing about, no attempt at a ‘featherlight’ touchdown.
It’s more along the lines of:
(assuming you have an appointed deck helper, which you should!)
Bonk! We’re down. Bellyhook please! Thank you. Tiedowns please!
(Note that if the captain will NOT give you a dedicated deck helper, who leaves the net -or whatever he is doing- the moment you appear in the sky, then you must drastically curtail the weather and wind conditions you fly in. I always had a deck helper.)
(the belly hook is just what it says: your helideck helper quickly attaches a line to your bellyhook, then runs back to a manual winch. He winds that in -quickly- and now you are safely attached -still turning and burning- to the ship) (see Note 1)
It may sound odd, but you get kind of blase about a ‘wild deck’. By the time you’ve done it a few hundred times…
Hey! No big deal…

“Been there, done that,
Been there, done that
Been there…. (yawn, bored)
Been there……………OOPS!! “

It’s understandable that you start feeling like an expert. A pro. As long as you make a good touchdown, even if the deck is rolling quite crazily, and even if you go from looking down into the waves and then up into the sky, although one is ‘alert’ it ends up not being the ‘heart in mouth’ experience it was when you first started out. Right?
Hey! No big deal…

Usually there is a net or a coiled rope to land on. I wouldn’t like to land on wet steel. That gets very slippery.
You very rarely slide on a net. It has happened to me, both before the belly hook was attached, and just afterwards (before the tiedowns were attached) and such a slide gets your attention.
I keep everything spinning at full rpm, even after the bellyhook is attached. Before the four tie-downs are attached.
The reason for that is this: If necessary, I could still punch the bellyhook release on the cyclic, and lift straight off. I’ve never had to. Close, but never. I keep a close eye on my helideck helper, and the moment the first of the four tie-down is attached, THEN I roll the throttle back. Only then. Once that first tie-down is attached (in addition to the belly hook) as far as I’m concerned, I’m down for the duration! If the machine was to really slide badly with only one tie-down attached (plus the bellyhook)… well, I’d yell like hell for the other three tie-downs! Again, it’s never happened to me.

It may sound odd to the pilot who has never flown off a boat: how can a pilot be perfectly relaxed and happy, when he is rocking back and forwards, blades still turning…? You get used to it! Not a big problem. You think…

“Been there, done that,
Been there, done that
Been there…. (yawn, bored)
Been there……………OOPS!! “

You do have a lot riding on that belly hook. That may be the only thing holding you from sliding at those extreme angles.
How much will the deck roll? With a load of fish hanging off the port side, you will be very, very impressed. Sometimes you will see an inclinometer on the bridge, or a device that measures the roll rate. How far will it go? It depends on a variety of things, such as:
* design of the keel (faster ships, narrow keel, more unstable side-to-side)
* weight of the fish in the net
* recovery stage of the net (how close is that tonnage to the center of gravity of the ship)
* sea state (a ship at rest hauling in the net will usually drift across the waves, making things worse)

Eighteen degrees, twenty degrees, more…..
It WILL get your attention.


A great photo of a sloping deck by Philip Bell

Helideck helpers always seem to start fiddling about with something inconsequential, instead of getting on with the important job of attaching the tie-downs, when the weather is at its worst. It gets to be really annoying when you realize that the helicopter is sliding, or straining hard against the taut belly line, and that mister deck helper ‘rotorfodder’ has his back to the helicopter and is just taking his time, fiddling about. That is when you might be tempted to take a lungful of air and let rip.
“GET MY F…ING TIE-DOWNS ON…!!! “
If a belly hook or a belly line should fail…. I’ve heard thirdhand stories of this happening, and that must be really interesting. Mercifully it is a rare occurrence.
Don’t think that every time you land on a ship, that the deck will roll that much. You may do several hundred landings, and not encounter anything too bad. That’s when you start thinking:
Hey! No big deal…

But rest assured, ONE DAY… sooner or later, you WILL arrive back with twenty minutes fuel, and see the worst of all those factors described above, working in unison, to really rock and roll that helideck.
It might not happen for months and months, but sooner or later, you WILL ‘land and slide’. You need to be able to NOT be surprised when you touch down, slide, and need to lift off again. Keep the cyclic vertical (relative to the deck), pull collective, and get out of there. More than anything else, don’t be surprised. Accept it. You are now slithering across the deck, even with collective full down, and it doesn’t look like you are going to stop. This is NOT the time to pause for a reflective moment, smoke a Hamlet cigar, finish your sandwich… just LIFT OFF (cyclic vertical to helideck initially, followed by slight forward cyclic input), and GO AROUND.
Once you have done it once for real, you will know it’s no big deal. But he who hesitates…is lost.
Now we have warned you in detail about one common tuna helicopter accident scenario…

This is a good time to caution you about what has also happened to many, many tuna pilots.
It’s happened to me. It’s annoying as hell, but it’s part of being a tuna helicopter pilot. Think about it beforehand, be prepared to react to it. Again, it’s not a time to smoke a cigar or finish your sandwich…
In my case, the time I remember best was when I was landing to pick up my captain, who was visiting another ship.
He was gambling again, losing all his money.
I always do a fly-by. I want to make sure they know I’m there, and about to land. I did on this occasion. I might as well not have bothered. I had just touched down, I had just rolled the throttle back to ground idle, (big mistake) and the moron below at the helm (probably the third mate’s assistant) spotted tuna off the port bow. Fully pre-occupied with that, and that alone, they hauled around. I mean, they hauled around. I immediately slid -violently- across the deck. Towards an obstruction.
The port navigation light if I remember.
It was a case of just violently whacking the throttle open. It’s a horrible sound, as tortured couplings scream in protest.
I’ve seen it described as a ‘snarling snatch‘, which seems a good description. The abrupt torque application does not do your drive train any good at all. But nor does crashing. You just have to lift off as best you can, as quickly as you can.
It’s rare, but it happens. You can swear and yell, but when people are tired, up early, and totally obsessed with catching fish… don’t be surprised what they will do.

Some helidecks and some helicopters are not equipped for belly hooks. The hook on the helicopter, and the cockpit controlled release mechanism costs a good few thousand dollars. This is too much apparently for some helicopter companies! If I was faced with a ‘no belly hook installed’ situation, this would radically affect my willingness to fly in certain sea states. I mean, it’s one thing to study a wildly rolling deck, time it, slap her down, and have a well trained deck helper dart out and attach a belly cable. Within a few seconds, ten perhaps, (once the helper has attached the hook, run back, and wound in the cable) you are reasonably securely fastened to the deck.
The worst risk period only lasts those ten seconds. Compare that with NO belly hook. Well, now you’re dependent on the deck helper attaching the four tie down straps. It takes longer. And you can seriously roll around with only one or two straps attached. So the window during which you can get caught by a serious rolling motion of the ship, is extended.
What, no belly hook and no deck helper at all? That’s totally insane. Are you going to do a two minute cool down? I hope so. Or you are going to coke your turbine blades. So you are going to wait for two minutes, totally unsecured, rocking and rolling, and then calmly climb out and go fetch your tie-downs? In a situation where the ship has fish in the net and is close to bringing them on deck? Are you going to finish that frickin’ sandwich first as well???
You are nuts. Or your captain is. To hell with that. I would have that situation changed in a hurry, or only fly in real calm weather, or walk the walk…

Bar talk is good for helicopter pilots. It gets you thinking. You will make up your own mind. I don’t want you to accept everything I say. But I’m hoping you will find it helpful to recognize the issues before they come hurtling at you, one after the other. Now, you will hear guys who have totally different views on how to approach a wild deck. They talk about coming alongside, studying the deck, and then sliding horizontally over onto it.
Sure, you study what the deck is doing. But that takes a few seconds, not twenty or thirty. Sure, you try and hit it right, and not when it’s rolled over at an extreme angle. But I really don’t think the approach considerations are radically different from what we talked about before! With a wild and rugged sea… why extend your time in the ‘avoid area’ of your height velocity diagram, hovering HOGE alongside ‘studying’ the deck? I would say ‘get on with it!’.
The landing is more critical. You must be positive. Don’t pussyfoot about. Get it on. Forget about style and finesse! And certainly: don’t start trying to do an extended hover! You will be asking for the deck to rear up and smack you on one side of the floats, or even come awfully close to the rotor disc.
That’s what I think anyway. Roll on the discussion. I welcome opposing viewpoints!

A heaving deck is worth respecting. The story goes that during the Falklands War, when Britain and Argentina were going at it over some cold, wind blown, rocky islands in the South Atlantic, that a British Royal Navy Sea King helicopter, loaded up with commando troops, lifted off an aircraft carrier. That’s an awfully big, heavy helicopter, coming off an awfully big, heavy boat. Right? It was a rough sea. So rough in fact, that the aircraft carrier was lifted up faster than the helicopter was ascending. It punched the Sea King right out of the sky, over the side into the drink. Everybody on board was killed. You will see my point. What is your little flying bubble going to do if it gets clobbered by your boat ? And how stable is that old tub of a fishing boat going to be? If a bloody big aircraft carrier can surprise two helicopter pilots, you sure as anything could -if you’re not paying attention- get surprised by your cute little purse seiner toy.


Notice the ‘bullet nose’ just visible under water

If you study your purse seiner, you will see many of them have a ‘bullet nose’ which is normally well under water. It’s part of the design for streamlining the hull under water. By the time the ‘bullet nose’ is rising clear up off the sea, and you can distinctly see daylight under it…and then it crashes down, sending white spray all over the decks…. that’s heave!
But don’t let it intimidate you. Once in a while, the ship really lunges up at you. But the effect is just like a sudden excessive rate of descent. Your reaction is the same. Up collective! So in practice, my mind isn’t distinguishing between what I am doing and what the ship is doing. I don’t think: “Oh my gosh, the ship is rearing up, now what shall I do? “
You just decide you don’t like the rate at which the deck is coming up to meet you, and you do something about it.
Simple thought process!

A new pilot here in the Gulf of Mexico came up to me with a question about landing on a ship.
He had not had a good experience that morning with two successive boat landings, and he was due to do head back again for another go. From our conversation, it was immediately obvious that he was uncomfortable. It was also apparent that he was studying the waves and the horizon, and then interpreting from that what the deck of the ship was doing relative to the horizontal. Hmmmm….. I told him to try a different technique:
“To hell with the waves and to hell with the horizon; just concentrate on the deck. If you don’t like the rate of descent, do something about it. “
Later that day he was back, beaming. All pleased with himself.
“That worked! “, he said.
This may not work for everybody, but I suspect it is possible to make things way too complicated, and to end up looking everywhere, instead of concentrating on…. the deck.

There is always going to be, sooner or later, that ‘coming out event’ in any tuna pilot’s life.
When you experience something that will provide you with endless bar stories. And an insight into a whole new world.
Hopefully,you will have a hundred or so routine, hum drum, ordinary boat landings behind you first. No big deal.
But when a purse seiner has its nets full, and they are just beginning to bring the catch on board, it will want to list to port quite spectacularly. Now you are looking for various factors to combine, to give you a thrrrrrrill.

* tonnage of fish in the net; the more the worse the roll; imagine 200 ton hanging off the side of a 1100 ton boat!
* how close are they to just about to bring the fish on board?
* design of the keel; fast boats have narrow keels, and more roll
* strength and direction of wind
* wave state
* speed and power of the winches
* design of the ship above the water line; Center of Gravity, arrangement of power block

The ship may roll back and forth, and this may really impress you. The ship will also likely end up across the waves. I’ve seen that happen many times. The helideck may go from nearly level to 20 or 25 degrees of roll. Here is another neat place where you must not try and hover! I have heard of guys getting a kick in the but as the ship rose up and swiped the rear of their floats, whilst the front of the floats were still four to six feet off the deck. What is your biggest worry in that situation? Tail rotor strike! I’ve heard many third hand stories of crashes due to this, but I would welcome some first hand corroboration.
The funny thing is, that with practice, these ‘slope landings on a rolling deck’ become lots and lots of fun.
There is nothing the ‘landlubbers’ can boast about that compares with this!
(except perhaps a high speed helicopter law enforcement pursuit!)

Some people talk about ‘ski-ing down the mountain’. (It’s actually more like ‘slithering very carefully down the mountain’, in order to prevent setting yourself up for a roll-over accident. But the word ‘ski-ing’ does convey the general idea very well) (you will hear it alleged that this term was dreamed up by some dozy Irishman, but I officially deny all knowledge)
What they mean by that is that they are not trying to touch down in the middle of the helideck. That would involve a slope landing with a difference: the slope is moving, undulating, and doing so in an erratic and unpredictable fashion!
What they do is that they land “on top of the mountain “, the deck edge on the approach side, (starboard, right hand side – mostly, not always) with the floats just on the deck, and the tail rotor stuck safely out over the Ocean. Then they calmly wait until the boat rolls to its steepest, and simply ‘ski’ down the mountain. (read: “slither very carefully “) It works really well. You can wiggle the pedals as well. The only problem is that sometimes you ski a bit fast, and then you can’t stop, even with collective full down. The collective in this situation almost works like the gas pedal in your car. If you lighten the load on the skids by raising collective, you will ‘ski’ (slither) faster. And the other way around. Usually there is no more than a six inch ledge around the helideck, so it’s quite easy to clear. Plenty of collective, ready with the ‘power pedal’, cyclic vertical for the initial lift-off, and then plenty of forward cyclic to keep the tail rotor away from the deck, and “Zip! ” off you go for another play! Sounds a little crazy, and people get excited about the subject. I watched one pilot beating the table with his fist and shouting that this was “impossible “.
No, it’s possible. Easy even, when you get used to it, and whole lot safer than wobbling about in the middle of the deck, trying to perform a ‘classic slope landing’ on a deck that’s rolling to 20 degrees or more. But, for sure, it’s a technique you must build up to very slowly and carefully. I cannot possibly over-emphasize the need to be super cautious. A Bell 47 float will pretty well bump over most (not all) deck protrusions, but a Hughes 500 SKID (different design) will NOT. Watch very carefully for anything that might possibly cause a roll-over. Again, if you want to start an argument in a bar, just bring up this technique. There will be guys who will say “Sure, I’ve done it. When the boat was really rolling like crazy. It’s okay as long as you are very careful. A lot safer than trying a slope landing… ” There will also be guys who will jump up and down, and tell you “it can’t be done “, or “it can’t be done safely “. “Don’t do it… “
I caution you to be super careful. But I would be amiss if I didn’t give you the heads up on this, and give you the chance to think about it.

A picture is worth a thousand words, and sooner or later somebody will send us a link to a YouTube video that shows this same exact thing.

Sometimes the deck will not ever roll level at all, but stays keeled over at a constantly changing angle.
Again, this is very disconcerting until you get used to it, and after that it’s glorious fun. You modify the ‘ski-ing down the mountain technique’ a little, that’s all. You land on the ‘pinnacle’, which is the approach side of the helideck, sticking up.
It’s the highest point of the helideck now. For a second or two you are balancing (perfectly under control) around a fulcrum on the very top of the pinnacle, with only a very small part of your floats making contact with the ship. Your tail rotor again is stuck happily out of the way over the water. Now you simply carefully lower (around the fulcrum) the front of your floats down so your floats are now parallel with the sloping deck. And ‘hey-ho!’, it’s ski-ing time again!
(read: slither very carefully down the mountain)
As long as you ‘think tail rotor’ and never haul back on the cyclic, you’re safe.
Pilots who’ve done ‘forty hour helicopter add-on’ ratings to their fixed wing Commercial License (a stupid system, says I), seem especially prone to hauling back on the cyclic at all sorts of inappropriate moments. (I speak from some interesting CFI experiences of mine…) Especially guys with taildragger time! Bad news on a tuna helideck! Kick that habit!

This is perhaps a good time to chuck in an anecdote from the Gulf of Mexico, to illustrate a point made above.
Remember where I was talking about the collective lever in some circumstances working almost like a gas pedal in your car? The more ‘up’ it is, the quicker you go, and vice versa? This at first glance puzzling statement is well worth re-visiting, especially for the new tuna pilot, the sprat ‘anchovyhead’. Remember, we are trying to get you to think things through for yourself, and to visualize situations developing, from the comfort of your armchair, before… the real, real thing.
I try hard to be approachable for the new guys. Many are intimidated by the hierarchy, Lead Pilots, Area Managers, Instructors… Some of these are very approachable and human. The odd one… Well, the nett result is that a new-hire pilot who makes a mistake, and gets away with it without actually breaking anything, will probably sooner or later be looking for a ‘Father Confessor’. It’s a very human reaction, especially when our young friend doesn’t quite understand what the friggin’ hell… actually happened. One such worthy did me the great compliment of choosing me, and I always feel both honored by the trust and very anxious to help. This young lad had frightened himself. It had happened on a platform here called “Vermillion 245 “, which is a mean, tight, badly obstructed helideck, about eighty miles out. He had been landing in winds gusting up to 38 knots or so, and well, the landing had not worked out. He said he slid sideways, and nearly hit solid steel with the tips of his rotorblades. I asked him as gently as I could how close he got. Our company requires thirteen feet of rotor clearance. (Ha! Don’t expect that on every tuna boat!) He looked awfully sheepish, and admitted it couldn’t have been more than three. Maybe less…
What was worse, in his mind, was that he couldn’t quite the hell understand what had happened. I told him he was doing the right thing, asking, and together we sat down to figure out what was going on. It took a little while, but what we came up with was this likely scenario, which has some ramifications for your tuna boat flying.
Firstly, he had been pre-occupied by the position of the fuel hose.
Coming in on a northerly heading (030 degrees or so), he would have known the fuel hose was on his left (awkward, for the refueling point on the Bell 206 is on the right).
Secondly, he was pre-occupied by all that steel stuff, on his left, rearing up at him, on a small (by Gulf standards) helideck.
And the next thing, he was sliding sideways, and scaring himself!
Experienced pilots will already be able to guess what probably happened:
1) pre-occupation with fuel hose: tendency to turn a little left towards it, to ‘make the refueling a little easier’.
2) pre-occupation with steel obstructions: tendency to turn a little left, to ‘see it better’.
3) But now the crosswind component is building up. We’re no longer perfectly into wind.
4) There are buildings to the north of the helideck. Risk of weird currents and vortices.
5) The result? A slide towards the left. The helicopter is being pushed towards the very obstructions he was worried about.
6) The key question: where was his collective? Up? Down? Half up?

On the last question, he thought about it for a while. The very fact that he needed to think, already told me the answer.
He eventually reckoned it was not all the way down. And that… will do it. Yep, you will slither, very easily.
You have GOT to get off the ‘gas pedal’. Whether you are slithering forwards or sideways, you still need the weight of the whole helicopter on the skids. He was happy, once we talked it through, and off he went a wiser pilot.
Now I know it’s SOOOO easy to snort at this, make judgmental comments, and generally complain that this is just ‘basic flying’. Listen, amigo: how many people get hurt -or even killed- by mistakes during ‘basic flying’? It’s easy to criticize, but it’s perfectly likely that he had never -ever- before encountered quite that particular set of circumstances. Very, very human.
On the tuna boats… you really want to be aware not only of the fact that the lever needs to be all the way down for you to stop slithering forwards or sideways. How-EVER… you ALSO need to be aware and NOT be taken all aback if you find yourself in a situation where the lever IS all the way down, and you are STILL sliding! That precise moment is a real bad time to have a brain short circuit, because you have never seen that situation, and never ever thought about it…

We’ve made the statement that ‘any pilot will welcome some sort of headwind component as he comes in for a landing’. I’d like to go through that a little more in detail. Usually there is a windsock on the very bow of the ship. Think of that as ‘twelve o’clock’. The helicopter parked on the helideck has got its nose parked towards ten-thirty o’clock, and its tail towards four-thirty o’clock. (looking down from God’s balcony) There are some weird exceptions to this.
Now. Coming down the latter stages of your final approach you are affected by an airflow which is the resultant of the forward speed of the ship and the prevailing wind. Right? Okay, you may well have some (or quite a bit) of right cyclic in, and be shushing along sideways as well as continuing your approach forwards and down. Now if that resultant airflow is coming from somewhere between ten o’clock and twelve o’clock, then you might be forgiven for thinking that such a relative airflow is ideal, right? Well, it is, up to a certain point! (more below…)
If the resultant is coming from, say, two o’clock, you need to start considering another possible problem. Basically, there will be a limit to the amount of ‘into wind’ ‘right cyclic’ you can apply. If you have a very strong resultant wind coming from your right (on final approach), you might run into a situation that will surprise you the first time. Remember the helideck often slopes slightlyup towards the bow of the ship. You can easily enough touch down right float first, with full right cyclic applied. So far, so good, you might think. But, as you lower collective, you are in effect also at the same time reducing the ‘effective’ tilt of the rotor disc into wind, or, if you like vectors, you are reducing your forward bow-facing thrust vector. If that makes sense.
CAUTION: The net result… can be a nasty ‘slither’ to the left, towards the back of the helideck, and towards the aerials and the radar/Immarsat dome! If you’re not expecting it, and you’ve never even thought it through beforehand, it can be frightening. If you hesitate with the lever neither up or down, you can really slither back. Usually, once the lever is up or down, the slide will stop. Usually. The problem of course is ‘what if it doesn’t’! In that case, you’re really misjudged the situation. You would not be the first tuna pilot to lift off again in a panic, your disc close to expensive aerials and radar domes, and inexpensive but terribly solid and unyielding steel!
Yes, I’m laboring the point. You will see now why I brought in that Gulf of Mexico anecdote about our friend on Vermillion 245… It’s an important concept, and has caused many, many accidents.

There have been cases of guys sliding rearwards, hitting the tips of their rotor blades, and still lifting off (in a panic) with their damaged blades. There have also been cases of guys electing to stay put on the deck, and they have slithered aft, demolished stuff in a shower of sparks, and just left it there! Your mechanic will not be pleased!

With experience, you will read the signs beforehand. I was flying along this morning, past the Losap Atoll near Truk (just thought I’d drop that one in, all nonchalant, y’ know), and I was trying to figure out what sort of damn lies I was going to tell you today. I noticed that it’s not just a case that there is more foam and spray on the waves that tips me off that the wind has picked up seriously. But what starts ringing alarm bells is when the foam really ‘hangs around’. What I mean by that is that the foam doesn’t get gobbled up by the next wave that comes along. It rides up and over the next wave, and sometimes it persists for a whole bunch of waves. Now I know the wind has really picked up! If the wind is that strong, and the direction of the relative airflow over the helideck IS two o’clock or so, then simply ask the ship to turn more fully into wind. Now the relative airflow, that resultant, is more like twelve o’clock, and you don’t need to carry all that into wind ‘right cyclic’.
You can also ask the ship to slow down. Half speed will do nicely. Too slow, and the ship seems to roll a lot more.

Two issues at this stage!
(i) Judging wind strength and direction
(ii) ‘asking the captain to change course for you’

(i) You will judge wind direction from the spray pattern. The spray and the foam are not blown forward by the wind as you might expect. It’s more a case that the wave moves forward in the direction of the wind, and the spray and the foam ‘fall over backwards’ on the wind side of the wave. This provides a strong indication as to where the wind is coming from. I note the direction of the directional gyro. Say ‘030’. Then, no matter how I twist and turn, a quick glance at the directional gyro reminds me of where the wind is coming from relative to my flight path. You should always be aware of the direction of the wind -like any helicopter pilot- and be aware that it can change! You will learn to judge wind strength remarkably accurately by the amount of foam and spray. There is just a certain ‘flow’ of foam and spray across the waves, and the way it ‘hangs around’ that warns you when things are getting really neat. Fun flying. Practice! Experience!

(ii) (Heck, I’ve had more arguments with pilots about this one…) There is nothing wrong with asking the ship to turn. Or asking the observer to ask the ship. Or, if your observer speaks English when he wants to, and not at all when he doesn’t, just point vigorously at the ship and make a turning movement with your hand! In the direction you want.
He knows…
The problem is… guys that have been out here a long time rarely can be bothered. You get that comfortable with your machine, you just tend to plonk it on and forget about it. Occasionally I will ask the ship to turn, but not very often. (they always do, by the way, without a grumble).
On starting the blades, I might ask the ship to turn or slow down, because I worry about a tailboom strike at very low rotor rpm. But it doesn’t happen very often that I feel the need to ask for this.
Now when I started out on the Tuna Fields, it was a whole different kettle of fish! I very often asked the ship to change course for me. Hell, I was nervous! Mostly they did, and occasionally they didn’t – at first. I would ask my observer to ask the ship to turn. He might be in a bad mood, and decided he didn’t understand. Okay… Then I would circle. And circle. And circle. And the fuel guge would go down. And down. And down. Until my observer suddenly remembered he could speak English again. “Why you no land? “
“I need ship to turn! Strong wind! Fong tai-tah!
There would follow the Asiatic equivalent (I think) of “Move the friggin’ship! ” Problem solved… By the time I was no longer a “sprat fishhead “, I was much more confident. I’d usually just plonk her on.
What I was actually doing, not consciously, but just sensibly, was ‘flying to my limits’. The smart way, I reckon.
Now some guys come out to the Tuna Fields, and they seem to think (or, worse, are led to think by other pilots) that they are letting the side down if they ask the ship to turn. That it’s some kind of ‘admission of failure’. That ‘real Tuna heads’ never -ever- ask the ship to turn.
Poppycock. “Safety First “. If you think you’re getting in a bit deep…. head for the shallows a bit.

Every night at 19.00 hrs, or thereabouts, if there’s other helicopter purse seiners about, around here we listen in on the two meter frequency 144.475 MHz. Sometimes it’s nice to yap. Sometimes it’s nice just to listen. Sometimes you don’t even let on you’re there, and find yourself quietly creasing up all the time.
Thus there was a forty-five-ish helo driver up one night, who I shall call ‘Bill’. (Not his real name)
Bill was out on his first fishing trip, on a Bell 47G2. He was enjoying the microphone. He had been on a tuna boat about three days. Bill was kinda… well, he wasn’t unobtrusive, put it that way. He told everybody that wanted to listen, and even those who didn’t, how he had over ten thousand hours, and had flown everything from Chinooks and C-130’s on down. The more you listened to him, he knew everybody, was an authority on everything, and his acquaintances sounded like a roundup of all the leading lights of the helicopter industry. It sounded just a little bit… like that he was going to do us all a favor and show us how it’s done!
A while later, Bill went to bed, and his mechanic came up. At this stage, sitting up on the helideck in my machine, enjoying the night, and the distant -almost lost- lights of resting ships, I started laughing to myself. It wasn’t what he said. Rather, it was what he didn’t say. I shall call our mechanic Alan. Several people questioned him.
“Hey Alan! Sounds like quite a pilot you’ve got there! “
-Yeah.-
“Sounds like he’s seen some stuff, eh? “
-Yeah.-
“You don’t sound too happy, what’s up? “
-Don’t ask.-
“Uh-oh. Like that is it? “
-Yeah… it’s like that…-
Now I should mention I know Alan, and he is a really good wrench. He’s also got some five years of tuna experience. He’s seen lots and lots of pilots. There’s a man who can really, really help a newbie Tuna pilot.
If… the pilot asks, and listens.

The next morning… it was windy. It was real windy. Forty plus knots. Spray flying about the helideck. Long shuddering crashes reverberated through the whole ship, as she rode up and up on high waves, crashed back down again, struggled on up… and crashed back down again. The sea state was rough. BIG waves. My observer, an old hand, would not have flown if the captain had ordered him. And anyway, I wouldn’t have dreamed of flying. It’s virtually impossible to see fish or logs anyway when the sea is that wild.
As for Bill… you guessed it. He was flying! I was curled up comfortably in my cabin, reading a good book, so I sadly missed it all. Bummer. But I heard all about it afterward -in glorious technicolor- on our chat frequency 144.475.
Poor old Bill tried a tailwind approach, with forty knots up the chuff. He tried a whole bunch actually. He went around three times, fishtailing merrily, and lost rotor rpm so badly on one go around that one float kissed the wave tops. His mechanic had several heart failures, all on the same morning. Then Bill, when he finally slithered to a terrifying stop, got out and started shouting at the mechanic! The machine had ‘no power’ and the mechanic was obviously a completely incompetent moron!
I would love to know how many times good helicopter mechanics (a pilot’s best friend) have been accused of incompetence on the subject of Bell 47 engine power! It’s not a turbine… it’s not a Huey you’re flying. There’s enough power to do the job if you’re careful, sensible, and current. If you’re not current, or new to the game, just build up slowly.
It’s really not that difficult, and there’s no great mystery about flying helicopters off tuna boats!
Mostly, it’s just common sense.

Occasionally, you will hear stories from pilots who say that their captains will not turn the ship.
It’s difficult for me to comment, because I’ve never experienced utter non-cooperation. It doesn’t make a whole lot of sense, because a purse seiner is twisting and turning all day long! It’s not as if it’s some huge Ocean Liner heading for one place only, and nowhere else. But I wonder to what degree what is perceived (by pilots) as ‘utter non cooperation’, or, to put it another way, ‘sheer bloodymindedness’, is often just a lack of understanding, lack of communication, or a complete frustration and bewilderment with these weird and wacky pilots! I will leave it there for now, but I want to return to this important subject under ‘communication with the captain’.

I fly a lot of tuna approaches with a tailwind component (rather than have the ship turn), but I have built up to it slowly. I STILL have my limits, and there is a point beyond which I will not go. Turn the ship please!
I learned one lesson about tailwind approaches when I had only had a few hours on the Hughes 500, and I was fresh off six months and 350 hours of Bell 47 Tuna time. I did a tailwind approach to the deck, and ‘lost it’ just crossing the deck edge. The tail kicked out violently to the left, and I went around having frightened myself! It’s the only time that’s ever happened to me, and it reminded me of guys who have been flying a slow, gentle old Piper Cub, and then climb into a hot-rod Pitts Special. A Pitts is a lot ‘shorter coupled’ than a Cub (the rudder is much closer to the vertical axis), and it just requires a faster and more positive reaction on the pedals. In a similar way (I think) the Bell 47 has a much longer tail than a Hughes 500. I reckon you’ve got to be just that bit quicker on the pedals with a 500 on a tailwind approach.

Some guys… will pooh-pooh all this ( “tough guys “), and proudly state that they will approach the helideck with any strength tailwind. Don’t listen to them. On two occasions, after some of these heated bar flying sessions, I’ve later had guys come back and admit to me that they had afterwards ‘run out of left pedal’ (power pedal) and scared themselves! Now, all of a sudden, they realized what I was warning about! Oddly, there always seem to be the guys who want to come across as ‘tough’. Helicopter tuna boat landing problems are best dealt with calmly, and rationally, by thinking about the aerodynamic issues. The advice just to be “tough ” was handed out on a forum a while ago, and I see it drew a pretty furious reply from another tuna pilot. I see his point: your helicopter doesn’t respect you, no matter how tough you think you are. She just answers to your hands on the helm. Remember, remember, as you approach from the starboard side for landing, the aerials, the radar dome and all that other expensive stuff is on your left. So if you’re running out of left pedal, that means your tail rotor is heading for trouble!

This is the right time to refer you back to where, in Chapter 3-A, I said:

“You will also see another, very important reason later on, why we try and fly an approach with a low power setting, and why we try and avoid coming over the edge of the deck pulling a whole armpit full of collective. I shall come back to this mysterious reason later, which I shall technically call the “Oh Shit! Now what?! reason “.
That reason – which we shall go into in Chapter 3-B – is tied up with the problem of ‘relative wind’…. “

I was watching another pilot, a truly charming Korean gentleman who I shall call Mister Kim. (not his real name)
I really liked him, he was always so pleasant, soft spoken and charming, but he also worried me.
He had been, for the longest time, the practitioner of a vertical landing. He was one of a small number of pilots who would arrive overhead at 200 feet, and then basically just ‘hover-waffle‘ on down. Well, some of the guys had been talking to him, and he was trying a different technique. In a more orthodox manner, he was now approaching the ship, in his Hughes 500, from the starboard side. Unfortunately, he was using the low approach, described previously. At times, his technique bordered more on the super low approach, also described previously. His ship was a sleek and fast Korean vessel. She was making a good sixteen knots. Into a twenty knot headwind from just right of the bow. From about two o’clock direction.
And she wasn’t slowing down.
That’s a relative wind of….? Yup. Thirty-six knots or so.
And here comes Mr Kim. Hughes 500. Low and slow. Because he’s nervous, he’s taking his time. Good thought, but not a good time to pussy foot her in… He’s approaching the helideck, more or less level…. I’m nervously watching… he starts sinking just a little bit… I’m thinking to myself “Don’t pull any more power, Mr Kim!!! “…. he pulls a little more power to pop back up to the helideck….. and the tail kicks violently left, just as he’s crossing the deck edge!

RANGARANGARANGA!!!!….RRRRRRRRRRRRRRRRRRRRRTTTTTTTTT!!!!!!!!!!!!

I watched, mouth open in horror, as he crashed good and hard! His tail rotor had just demolished the antennae, chewed its way through whatever tubing it could find, and the helicopter fell heavily onto its left side, broken blades spinning wildly. He stayed on the deck. Lucky…. it could have “walked itself off “, with the broken blades doing the walking!
Pretty soon all the noise stopped. Eventually, dear old Mister Kim could be seen, clambering out of the wreckage.
He was shaken, but alright.

That night, on the two meter chat frequency, the word went around that he had suffered a tail rotor failure.
Not so, I argued. I saw it. That was not a tail rotor failure. It was a pilot failure. People argued. It got technical.
Then it got heated.
So armed with all the discussions we have had, how would you assess this event? Was it a tail rotor failure?

It is possible to get really technical about this, and if you so wish, you can draw all sorts of vector diagrams.
I prefer a more simple, intuitive explanation. A pilot’s thought process.
I have said many times you don’t want to be ‘high hover taxying’ in to the helideck, HOGE, in the ‘avoid area’, with a lot of power. You don’t want to be pulling a whole lot of collective. You want to be on a positive, stabilized, descending approach, with a relatively low or moderate power setting. And with this accident,you see another really good reason why.
The helicopter, the slower it goes, loses its own forward momentum, and loses its own established airflow. It becomes more and more influenced by the Ocean wind. But in this example, that Ocean Wind is coming from two o’clock! It’s coming from the right of the nose (bow) of the ship. Pretty well a direct cross wind for you! And you are going slower, and slower, pulling more and more power??
I know you’re trying to be careful… but you’re not helping yourself. Your helicopter wants to yaw into wind. Weather vane into wind. But you don’t want that, so you’re applying left (power pedal) to keep your nose pointed in the direction of travel towards the helideck….there comes a point (a horrible point) when you are basically asking too much from your poor little helicopter. You are overpowering the ability of the tail rotor system. The little Hughes was doing its best…. but the last straw, the straw that broke the camel’s back (and the rotor blades, and most of the rest of the helicopter) was when Mister Kim (on a low, more or less level with the helideck approach) sank down just a tiny little bit. And corrected for this, (while I’m thinking : “NO,NO! “) by pulling “just a little more collective “. If you’re lucky, you’ll feel the left pedal hit the stop. If you’re not, like poor Mister Kim, or if you don’t react (because you have never read up on this situation, so you don’t really know what the hell is going on…)

RANGARANGARANGA!!!!….RRRRRRRRRRRRRRRRRRRRRTTTTTTTTT!!!!!!!!!!!!

Make sense? I sure hope so. This is a common, common “Oh Shit! Now what?! accident cause.
This accident had an interesting sequel.
A few years later, I was Chief Pilot with Tropic Helicopters, and I received a resume from… mister Kim.
He’d been fired, I think he’d broken something else this time, and he was looking for a job. A few weeks later, he was on Guam, and he called and we visited together. Such a nice man.
I brought up his accident.
He smiled, that serene, calm, Oriental smile, and said politely, in his broken English:
“Tail rotah- failyah…. “
No, Mister Kim, I said, not tail rotor failure. And I explained, carefully. When I was finished, he smiled, politely, and said:
“Tail rotah- failyah…. “
I sighed, got a pencil and paper, and made some elaborate drawings. I tried to explain very, very clearly, what I’d seen myself. When I was finished, I got:
“Tail rotah- failyah…. “
I didn’t employ him…

I once visited with a Hughes 500 pilot, who couldn’t believe his ears when I told him my ship was willing to turn into wind when asked. He sort of stared at me with disbelieving eyes, and seemed to think I’d stumbled on the Holy Grail! A ship willing to turn into wind for the pilot! Unbelievable! He told me I was ‘very lucky’! Hm! More on this later, under ‘communication with the captain’. For now, let me say I think it’s flat wrong -and highly dangerous- for fresh Tuna pilots to go out there, new to the game, and operate in the mistaken belief that ‘whatever situation the ship is in’ they just have to passively accept this, and make the best possible landing attempt.
Or, worse, just ‘tough it out’.
It’s your life! And your passenger. You are entitled to cooperation, if you politely request it. If you don’t get it, then radically -radically- limit sea state and wind strength you will accept for flying. And tell them why.

It is easy to fall into the trap of thinking that all ‘nice winds’ come across the ship’s bow. Preferably somewhere between ten and twelve o’clock! Ah-ah! Not so!
A really neat situation occurs quite frequently when the ship is moving along at 14 knots one way, downwind, and it has a similar strength wind up the stern! Guess what. The helideck is wind calm. Easy. Great for starting up and shutting down your rotors. No risk of ‘blade sailing’ especially on shut down. If you were to ask the ship to turn into wind, or if the captain decided to try and ‘help you’, you would have something like 28 to 30 knots to contend with.
Hard work in a Bell 47. ..
If the ship is doing 14 knots, and you have 20 knots up the stern, you’re still much better off landing with a 5 or 6 knots tailwind component, than getting the ship to turn into wind and taking 34 knots on the chin.
Remember also that the ship may ‘ride’ much smoother going downwind. You would not be the first Tuna ‘anchovyhead’ pilot who asked the ship to turn into wind, and then found out to his dismay that it was now pitching and heaving like a walrus on a pogo stick.
You’re much better off accepting a small tailwind component. It’s really nice standing on the helideck, not being blown about, watching wild waves and spray lashing madly about the place. All cocky, you even decide to triflow the strap packs.
You get up the ladder with your spray can, and then the captain spots a breezer behind the ship somewhere, hauls around on the helm, and there you are, you dumb schmuck, with the deck leaning over crazily, perched precariously on top of a rickety old step ladder! Yep, that’s you, clutching wildly for support, with 34 knots whistling around your ears and the ladder sliding, wondering what the blinkety-blink-blink made you ever decide to set foot on that blinkety-blink-blink (PEEEEEP!!!) #@!!FK@!N old Taiwanese tub in the first place! Ah, my friend, such is the pilot-mechanic’s life on the open Ocean!

Finally, you may wonder what happened to Bill.
Our hero, described above, of the “I’ll show’em ” Bell 47 multiple go-around airshow.
As I understand it, he just did the one trip, six weeks, and quit! Back to Chinooks, I guess.
His final comment, on the subject of those who would make their living off chasing the Tuna, is noteworthy:

“These people are weird!

Francis Meyrick
(c)

Note 1: The belly hook installation costs money. It has to be FAA approved. Cheapskating helicopter operators have increasingly done away with them. It gets justified with the claim that you “don’t need it “. Poppycock. Not true. Properly used, it is a good/great additional safety tool in severe conditions. Some of us would say “essential “.

Last edited by Francis Meyrick on September 17, 2012, 4:31 pm


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3 responses to Moggy’s Tunaboat Helicopter Manual Ch.3-B “Wind, waves, and wild decks “

  1. Great read!"Walrus on a pogo stick"…I have to find an occasion to plagiarize this!Thanks!

  2. When lifting off and landing when the deck is heaving. I am assuming you should take  off when the deck is on the way down right for TR protection? How about landing . when the deck is coming up seems like a better time to touch down is this correct.

  3. Hello, RS1

    1)  "I am assuming you should take  off when the deck is on the way down right for TR protection?"
    Um. You’ve got me thinking here. I’m honestly not quite sure I’ve thought about that so much. I just tend do "do it". (I know, that doesn’t help.)
    I’m inclined to say "No". Meaning, I think (when I’m trying to think of it) that I actually probably wait until the deck is coming up to close to its highest point, and THEN, I lift off, and let the deck fall away below me. I think that’s right. It’s an instinctive thing. But you’re right to worry about your tail rotor. Tropic Helicopters just had a fatal accident this last summer. Seems a take-off went wrong.
    2)  "How about landing . when the deck is coming up seems like a better time to touch down is this correct."
    Yes and no. Once you’ve done it a few times, you’ll probably agree with me that it doesn’t quite work that way. What tends to happen is that you stare at the deck, not the waves, or the horizon. You just follow the deck. Meaning,you act on the visual cues the deck is giving you. If you’re approaching too fast… do something about it (up collective a bit).
    And vice versa.
    When you FIRST start doing landings, your mind is really pre-occupied about whether the deck is going up or down, etc.
    By the time you’ve done a few…. it starts becoming automatic.
    I don’t really care WHAT the deck is doing relative to the horizon or the waves. I only care what the deck is doing relative to ME.
    Seems to me that the newbies are hanging alongside, "studying the deck".
    (looking everywhere, at the deck, the waves, the horizon…)
    The Old Pharts… just get on with it. Land the bloody thing.
    They are probably thinking "coffee".

    Having said all that… the hardest landing on a boat I EVER had, was in a Super Puma landing on a boat in the North Sea, in 60 knot winds.
    I was NOT the handling pilot. I WAS the SIC guy yelling "Too fast, too fast! Rate of descent! Rate of descent!"  Boobus PIC Pilotus beside me ignored me, and managed to be going down quickly as the boat reared up – quickly.
    It felt like it knocked the fillings out of my teeth.
    The heave was probably thirty feet plus. There is some serious skill and judgment involved here…

    It’s fun.  

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