20 August 2011

Crosschecking The Instruments

A commenter responded to my video below:

"Just how many of you are there to watch those gauges. If there is a problem do those gauges tell you first or does the change in sound or feel? "

It's a valid question. I can remember being sorta overwhelmed the first time I looked at the dashboard of a complex aircraft...
How can anyone possibly make sense of all that?

First, it's just me watching those gauges most of the time, Anon. My Nurse and Paramedic are in the back kicking death in the ass, so they're no help at all.

Now, think of your car. Most of us have owned a car with a speedometer, tachometer, water temperature gauge, oil pressure gauge, and maybe even an oil temperature gauge in the dash cluster. What did you pay attention to, mostly?

The BK117 I fly was built to be flown with either one, or two pilots. Watch the video again...
I always turn the lights on for the entire instrument panel as an insurance policy. Most of the instruments you see over on the far left of that panel are redundant instruments I have in front of me. If you look closely, you'll notice this bird even has THREE attitude indicators (artificial horizons if you like.) So I pay almost no attention at all to the left one-third of that panel unless something on my side fails.

The far right side of the panel contains the basic flying instruments:
Airspeed indicator, altimeter, vertical speed indicator, heading indicator, and the aforementioned attitude indicator. In this particular bird, the green rectangle you see at the lower right corner of the panel is the GPS... attached in an absolutely horrible place because in order to program it I have to manipulate the cyclic with my left hand to turn GPS knobs with my right. It's a pain.

In the center of that instrument panel are gauges for both engines and the transmission:
Oil pressure and temperature. Torque, (power being demanded), engine and rotor tachometers, and exhaust (or turbine outlet) temperatures. It's safe to glance at all these about as often as you'd check your rearview mirror in your car, because all these instruments are backed with warning (idiot) lights that would illuminate should any of them get out of normal operating limits. This would also set off a "Master Caution" light squarely in front of my face to say, "Something's wrong! Take a look at what's going on with your flying machine, stupid."

So it's not so overwhelming as it seems. The night I took that video was extraordinarily calm and I was able to turn the controls completely loose to handle the camera. On a night like that it really is a matter of monitoring the gauges by glancing at them now and then, and making minor changes in the controls to insure the aircraft is at the heading/airspeed/altitude I want.
(And your comment about how the aircraft feels or sounds is a valid one... the machine DOES talk to you, and better pilots may feel or hear a problem before any of the instruments indicate something abnormal is going on.)

Another commenter said something valid for that night...
I AM still trying to convince others I actually WORK for a living!


Jim said...

How do you let go of the controls? I was under the impression that the cyclic (especially) and collective always needed positive input?

I'm assuming there some way to trip the helicopter for forward flight and set altitude?

Greybeard said...

This bird has what is called a "force trim" system Jim, that will hold the cyclic magnetically where you set it. It works great until some outside force changes things, then you have to reset it.
On still nights it works well enough for you to take your hands from the controls to fold a map, check a reference book, etc..
Some of our machines even have autopilots! WooHoo!

Jim said...

Thank you! 9,400 hours fixed wing time and I've never even ridden in a helicopter. I'm embarrassed to be so naive about how they operate.

Even with force trim, you and your kind are still true stick and rudder aviators compared to some of us FMS jockeys burning holes in the sky.

Old NFO said...

Good response! IT's ALL about training and level of comfort! And yeah, nights like that you should pay them :-)

Greybeard said...

My advice Jim?
Never, NEVER EVER take a helicopter lesson!
It's like heroin.
(And will frustrate and amaze you.)

Anonymous said...

Anon here again. You mention a cyclic magnet in your response to Jim. When I was in Nam a lot of birds went down due to wounded pilots. Would this magnetic thing prevent some of the causalities? Helicopters must have come a long way quickly. Were you a Huey pilot?? COMMENT; You could not pay me enough to get in a machine that experts say cannot possibly fly, something like a bumblebee is dynamically unable to fly.

Greybeard said...

Anon again:
In my comment I simplified matters a little about the systems on the BK117. On it we have what is called a "Stability augmentation system" that helps dampen oscillations in pitch, roll, and yaw. You fly this aircraft like any other helicopter, by moving the cyclic. But you can fine-tune cyclic movement using a "China hat" on top of the cyclic that moves the cyclic slowly in whatever direction you push the button. The cyclic will stay in whatever position you move the China hat to, and that's fine so long as you're not in turbulence or don't encounter a variable gust. You CAN NOT take your hands off the cyclic for long... if you do, the aircraft will do a "dying swan" and roll out of control.

Hueys actually have a "force trim" system.
-Push a button on the cyclic and the magnetic force will release and allow you to reposition the cyclic, then releasing the button would magnetically hold the cyclic in your last dictated position. It was similar to the system in the BK in that you could not then take your hands off the controls for long or you'd get the same result as you do with the BK...

Our autopilot systems WILL fly the aircraft at the last assigned heading/airspeed/altitude. (Some will even couple up and fly an instrument approach.)
They are wonderful, but are almost prohibitively expensive on helicopters... I'm always surprised when I see one installed.

Yes, I am a VN vet. (Americal Division, Chu Lai, 1968-'69.)
Our unit there required you either to fly with the controls frictioned VERY snug, or with the force trim on, for the reasons you state...
If one pilot was shot, it gave the other pilot time to realize there was a problem and react by taking control of the aircraft before it did that dying swan thing.

And about your last comment:
What experts are you referring to?
Give me, (or most any other dual-rated pilot) a choice between flying the helicopter or an airplane and make safety the determining factor, and BY FAR most of them will choose the helicopter.
Ask me. I'm rated in airplanes and helicopters!
Airplanes are dangerous things.
(Helicopters have a terrible safety record mostly because the idiots at the controls do really stupid things with them, and the machines lend themselves to doing unsafe things... down and dirty, among the wires.)

On a Wing and a Whim said...

Thanks for the video! I was pretty amazed you were off the stick, and the VSI and attitude indicators were showing straight and level - thanks for the explanation, 'cause I was scratching my head on that, too!

I have stayed away from helicopters because I have a "seized-wing" and I love her very much; I shall not forsake her for anything [except my husband]. I can't afford to!

Still, in the way that my dual rated friend, The Gunny, has tempted me into taking my second and third motorcycle rides of my life, and shooting things I thought were too big a caliber for my old scars, one day his sheer glee at rotor-wings might tempt me into behind as behind the ball in a cockpit as I haven't been since my second flight lesson.