Moggy’s Tunaboat Helicopter Manual Ch.3-G “Descending to a Log & Blue-Out “
Posted on September 26, 2009
Ch.3-G “DESCENDING TO A LOG & BlUE-OUT “
So there you are, flying along quite happily at 800 or 1000 feet, and your observer spots a log.
He wants to see if there’s bait fish around the log, and if so, how they are behaving. He asks you to go down.
It’s nothing new to you, you’ve done it hundreds of times before.
It’s a beautiful day. Sunny, calm, and the water is emerald blue. Almost translucent. It’s good being a tuna pilot. Really, really good. You are becoming an ace. You know all this turbine time is going to do your career a tremendous amount of good.
You enter autorotation, and start on down, careful to keep the log in sight. Just then, a buddy calls you on the radio. You answer him, and exchange pleasantries. Your observer is pointing at something else. You follow his outstretched finger, but you can’t see what he’s indicating. Maybe he’s seen a tuna. You check your rotor rpm. All is well. You’ve done this a thousand times before. You’re feeling comfortable, relaxed and contented. Down, down…. a little turn….
An alarm bell is going off in your mind. You have time to think:
“Huh……!? What the……?? “.
The bone jarring impact stuns you. Your mind is reeling with confused audio and visual inputs. There is light, then shadow. There is sun, then bubbles. A tremendous amount of noise. The window frame. Something against your face. All of a sudden it’s cold. There is a strange, wet sensation. And now there is pain. A lot of pain, from all over your body. And it seems hard to breath. You are totally confused. Your chest hurts. You need air. The light seems to be going away.
And now, you’re dead. Simple as that.
You may at first have wondered why on earth there is here a whole chapter dedicated to such a straightforward thing as descending in your helicopter. Basic Private Pilot stuff, eh? It’s not that simple. Ask any Old Tunahead the reason this chapter is here, and, believe me, most will do a much better job of describing the risks verbally, than I can possibly do in print. In a nut shell, a lot of us suspect that simple descent has killed a lot of people. Some mysterious disappearances, that have never been explained, may come down to a few basic missteps. This is one of them. Why?
First of all, how are you going to descend? Are you going to enter a smooth, powered descent, no more than 500 feet per minute, or are you going to autorotate? Many pilots use autorotation. Others do not.
I belong to those who take their time. I slow the action down. In the Hughes 500, I set up a nice descent using about 20 per cent torque. I don’t-rush-anything. No matter how many logs we have already inspected that day. As you turn, the angle of the sun on the water changes. On a clear, flat calm, translucent Ocean, the changing relative position of the Sun brings with it quite amazingly different visual perceptions. And different perceptions of height.
As an example, when you are in a descent around your target log, you may come into the full glare of the sun. The whole area around the log will turn silver, and you may not be able to see it for ten to fifteen seconds. The observer, possibly your captain, may be messing about with his hook and rope, getting radio to attach a radio buoy. He may be talking to the ship. He will not thank you for losing the log! We’ve all done it, and had to start over looking for the damn thing.
But let me plant a seed in your mind here, and more below. When you are transfixed on that log, and you are anxious not to lose it, and when there is nothing else around, no ships, no oil platforms, no other logs… no houses, no streets, no mail boxes, no dogs, no pedestrians, no trees… from where do you get your visual cues relating to your height above the water?
I plan my descent and approach, with special consideration for a nice, into wind approach. If there is one. I don’t just ‘cowboy’ it on down. I fly a profile with due regard to the height velocity diagram. A lot of guys don’t bother, or don’t understand the height velocity diagram. It’s not just some theoretical, fancy-dancy who-gives- a-rat’s-ass academic graph, of curiosity value and zero real world application. (see Note 1) On the contrary, it’s put there by the manufacturer to help you live a long and fruitful life. And make many babies. And hopefully…. save him from yet another spurious product liability lawsuit. Coming through 300 feet is a serious ‘alert’ stage for me, but coming through 100 feet is a trigger for CRITICAL awareness. Life-and-Death awareness. Pay attention or pay the price Awareness. I have a mental Ground Proximity Warning System. Through 100 feet, and a cerebral alarm goes off:
“Teedle-deedle-dee! One hundred feet! “
I can still hear the Super Puma system…
Some guys, many guys, autorotate, and they are down quickly. But there are many stories told…
One is a famous one, handed down for many years, about a lad who is no longer with us. He used to autorotate apparently, and is supposed to have said on various occasions:
“Three times around the log, and you’re down! “
Three 360 autorotations around a log translates into a lot of height loss.. You’d wonder what altitude he was starting at. Well. There’s no soft way of saying this: he’s dead! And so is his observer.
Before we condemn, as pilots often do, and say “How stupid! “, perhaps we ought to remember that old saying:
“There but for the grace of God…go I! “
In the Gulf of Mexico, the operations manual of at least one company expressly prohibits intentional flight below 300 feet.
There’s a reason for that. A good reason.
I came to Tuna helicopter flying with a lot more flight time than many first trippers. That included plenty, plenty, of over water time. But I was still new to the unique world of tuna helicopter flying.
And this might be a good time for me to tell you another story against myself…
That story hopefully again will serve two purposes:
Firstly, to show you how easy it is to waltz innocently smack-bang-whallop into trouble.
Secondly, to remind you again, as I will say through out this manual, that I do not set myself up as the paragon of all virtues, the infallible voice of how to fly Tuna helicopters, and the Final Arbiter of all things right and wrong.
I know better. In Aviation, there is no statement you can make, but somebody will disagree. You could say the “Earth is round ” and somebody will say that from a pilot’s point of view it doesn’t matter, it’s essentially flat.
I am much more concerned with offering you the issues, and the suggested remedies, and encourage you to make up your own mind.
If you go fishing, I can guarantee you that you will meet up with some self appointed guru, who will tell you that ‘Moggy is full of it’, and autorotations down to logs are harmless. He will tell you that “he does it all the time “, and has “never had a problem “. Well, the dude we just mentioned above “never had a problem “, until he “got killed “.
I positively hammer on this point: the world over, all sorts of pilots, with all sorts of experience levels, in all sorts of flying machines, equipped with all sorts of bells and whistles, HAVE flown under control (CFIT) into the water. By day, by night, single pilot, dual pilot, commercial airliner, executive jet, big helicopter, small helicopter, pink and candy striped hang glider, over sea, over lakes, over rivers, over canals…. over Auntie Rachel’s frickin’ slime green fish pond…. I tell you, you name it, somebody has done it. I bet every single one of those pilots thought it would not happen to them. I’ve read accident reports of pilots with gazillions of hours….
SPLASH!….into the Ocean ‘Oggin…..oops…
Back to my story. I was new to the game. In a Bell 47. I hadn’t been down to many logs. We’d already been down to one. A nice, big one. A good ten meters. We’d attached a radio buoy, and that had gone well, and I was pleased, because it was only my third time or so attaching a radio buouy.
Well…. experienced Tuna Heads will probably already guess what comes next!
A while later, my observer pointed out another log he wanted to go down to. I checked day light, and it was getting on a bit, and we really needed to get a move on. So I autorotated, careful not to lose the log.
Mentally I was clicking off height, and as I reckoned we were approaching 100 feet, something suddenly set of a flashing red caution light. I distinctly remember thinking I was at about 120 feet above sea level.
Something was wrong! My eyes flew to the altimeter, and I was descending through 25 feet! In autorotation, at 1,500 feet per minute rate of descent. Yes, I saved the situation, with a pretty lively flare, but my eyes were out on sticks.
How in hell…!
The first log had been ten meters. The second log was only three! Unwittingly, innocently, I had allowed myself to be su-suckered into a really basic mistake. For shame! I really should have known better.
As so often, this was a combination of circumstances. The infamous ‘accident arrow’ trying to nail its way perfectly through a series of rings. Each ring representing a contributory factor.
* Mild concern about daylight
* Mild concern about fuel reserves
* a shorter 3 meter log, coming right after a 10 meter log
* a glassy sea
* inexperience in the Tuna Fields
* lack of Bell 47 time, and therefore concentrating a bit hard on the autorotation
* and a dose of stupidity….!
I don’t care what anybody says, but I know from experience that you get some really, really funny effects and optical illusions over water. You may have pretty good ‘perspective’ on your height above the water on a sunny, calm day, but when you simply turn, all that can change in a heart beat. The simple act of turning, and the change in the relative position of the sun, and the change in refraction, all can combine to suddenly really surprise you.
True Tales from the Tuna Fields:
1) One Tuna Head told me about carrying out a steep turn on a day with a poor horizon, and suddenly experiencing “instant vertigo “. No gradual onset. Boom! Instant. He reckons he rolled semi-inverted, and pulled a horrendous amount of G’s pulling through! And lost most of his height into the bargain. Ouch!
2) Another Tuna Head told me about looking to his left at a blurred horizon,and a featureless sea, and rolling 45 degrees left without even realizing it. He was in balance, and it was only the rising airspeed that alerted him. He looked right (where he had a better horizon) and couldn’t believe his eyes!
The expression ‘Goldfish bowl’ means different things to different pilots. I associate it as meaning ‘murky and hazy horizons all around’. It can happen when it’s hot and hazy, but it can happen when it’s foggy and clammy as well.
Now it’s easy to over bank.
In the Gulf of Mexico, a common rule for VFR helicopters is ‘500 and 3’. Meaning you need 500 feet vertical, and 3 miles visibility to fly. How-ever. If you are finding it impossible to distinguish the point at which sea becomes sky, and vice versa, then, regardless of visibility, you had better be super careful.
Similarly, if you find yourself looking down at a forty five degree angle to see the sea…. and you’re at 500 feet…. it’s time to turn around! (what does that make your inflight visibility?) (500 feet……??)
I was really tired one day, having slept badly. It was murky, hazy, the sea was slick…
I was really having to concentrate. To make matters worse, there was no attitude indicator in that machine.
After two hours of this, you can’t wait to find your ship. The GPS indicated she was dead ahead, but, hell, if I could see a sausage. I peered, and peered, and squinted, and searched, and suddenly… there she was, floating, five hundred feet in the air! I did a quick double take, and I realized that what I had thought was the horizon…. wasn’t!
That’s a real good way of setting up an unintentional descent.
I have some photos in this chapter, and they are just meant to alert you to the amazing clarity of the water sometimes, and the degree to which the water becomes ‘translucent’, and plays havoc with your depth perception, especially in a turn, or during a descent/autorotation. They are of some fishermen, on some ‘way out’ forgotten Atoll in the middle of Nowhere. They sure seemed very friendly, and were waving like crazy.
However, the best training aid by far, is an amazing YouTube video, posted by ‘Guamwalker’, for which I am very grateful.
The video was shot by the passenger it seems, and unintentionally, there is a good demonstration of how ‘blue out‘ could trap a pilot.
That’s a phrase I’ve dreamed up, at least I’ve not heard it used by anybody else before, and I think it’s just as dangerous as ‘brown-out’, ‘white-out’ or ‘black-out’.
If you watch the video closely, you’ll see he banks hard right after take-off. Looks kind of a bit low as well.
See that flash of blue-blue-blue? Imagine you were the pilot, looking at that…. can you see how -suddenly- if you’re not paying attention, you can become disorientated?
If I could sum up a descent to a log in a few words, then I’d say:
“Be careful! It’s not like descending over land…. “
Note 1: for an excellent discussion of the height velocity diagram (also known as “the Deadman’s curve “), and the relevance to every pilot’s daily grind, see Ray Prouty’s classic work, “Helicopter Aerodynamics “.
“No matter how clever the pilot is in juggling the energy in both the entry into and the flare from the autorotation, there remain some combinations of initial altitudes and speeds from which he will surely crash… ”
On Page 193 and further he uses the analogy of water leaking out of a bucket. Very interesting, and thought stimulating!
Note 2: Oh, boy! Dan Munteneau pointed out, in a recent conversation on Facebook’s ‘Tuna Helicopter Spotter Pilot’, that Blue-Out also accounted for a recent TAKE-OFF accident. This one is worth visualizing, and thinking through. Don’t throw stones! Remember the house you reside in. A Tuna Helicopter successfully dropped a radio buoy (flat calm surface, glassy mirror, blue sky & sun) and then attempted a take-off. And crashed. In Dan’s dry words, I quote:
Dan Munteneau: “No vertical log. The radio buoy was deployed successfully. The front of the floats contacted water while the machine was nosed down on departure. And the rest is history. Both pilots and observers on both accidents OK. “
Here is the rest of the conversation. New guys… listen up…
Francis Meyrick: fascinating. Glad they were okay.
Dan Munteanu: Fascinating,alright..
Francis Meyrick: I mention ‘blue out’ several times, not sure if I mention ‘blue out’ occurring on take-off after dropping a radio buoy. I might need to re-visit that chapter. The manual is out. Working on the next 5 or 6 E-books… time, time.
Francis Meyrick: autorotations to a flat, calm surface, blue sky, like you say… THAT is where I’m convinced there have been unexplained fatal Tuna Fields accidents. In fact, many, many. That sudden translucency of the water… until you experience it, very hard to describe.
Dan Munteanu: Calm ocean ,glossy water and your own downwash ripples being left behind while you transition forward,coupled with a bit of an aggressive nose down ….BAM!
Francis Meyrick: “…and your own downwash ripples being left behind while you transition forward, ” Another good point. I’m making notes here…!
Francis Meyrick: I’m hoping eventually, once all the E-books are out, to produce some hard copies. It’s not that straight forward to tweak an E-book (you have to upload a whole new manifest each time you make a change). But, all feedback is good, because I do plan on updating & improving all the time. Anything else you think is missing in the manual, or you would like to expand on, I’m all ears.
Last edited by Francis Meyrick on November 3, 2015, 8:06 am