Probably a stupid question by a non helicopter pilot
 

Hey guys I'm a GA pilot and no practically nothing about helicopters. However last week I saw these strangest thing and I'm trying to figure out what I was seeing.

I was driving up a relatively steep hill in a heavily forested area and was very surprised as I topped the hill to see a helicopter about a half mile ahead at a very low altitude.. less than 200 feet.

My immediate thought was we got a chopper in trouble and there's tons of forest here and he must be looking around the road for a parking lot to put it down...

Instead he continued to follow the road about 50 mph. A little faster than traffic, and swerving a little bit left and right and making a few turns that I would call uncoordinated if it was fixed wing.

After a couple of miles he banked away from the road, again it didn't look pretty.

I don't know much about helicopters but I'm pretty sure it was one of the Robinson line because it had the very tall post for the rotor. If so, I know they are often used for training but I'm trying to imagine why anyone would be training at a very low altitude in a place with so little options for emergency landings.

I was concerned enough that I actually checked the news later but thankfully nothing happened..

So any ideas what I might have been watching? I'm pretty good with heights. He was very low and there is no way I would ever repeat his show in a 172.

During my fixed wing to rotor wing training the notion of being high to enable greater choice for forced landing areas was balanced off with the concept of not being needlessly high if something goes wrong - less time to get to the ground. If there are no good landing area choices anyway, then being lower is better, 'cause you're going down anyway! While ferrying an MD500 back near the Canadian arctic, I went up to 8000 feet for the spectacular mountain view. The [very experienced] rotorwing pilot I was flying with was really squeamish that high, and asked me to get back down close to the ground as soon as I'd had my look around!

Yeah I totally get what you're saying.. If he was 500 or even a thousand feet up I never thought about it for a second...

But I'm assuming that auto gyro glide paths have to be similar to fixed wing at best? If so, I couldn't imagine finding any place to put it down with an engine failure.

Of course I realize the odds are low for an engine failure, but it's the part of the envelope I was always told to stay out of :-)

What country? I am guessing the US...... he was probably doing power line inspections......wee conduct those anywhere from 100 to 300 feet AGL. Out west we use Bell 407's, Astars or twins for that work, but I do know back East they use Robinsons occasionally.

Some helo pilots seem to be afraid of height and get edgy if above 1,500, source of worry is a main transmission failure they said, had one such US Army graduate so took him up to 16,000, we regularly flew at 10,000 on a transit. When doing my training on the Huey it was standard practice to go to 14,000 for a vortex ring demonstration, being military we wore parachutes for the exercise. One military required parachutes above 5,000 in helos, which was a nod towards transmission failures I guess.

Yep US and that makes complete sense... Not a student, he was a bit erratic cuz he was having to stare at the power lines.. thank you so much makes me feel better;)

Yes, there is an uncomfortable feeling of flying high AGL, with all that glass around and the down angle field of vision, it’s not like an airplane looking forward at the horizon. The blades also have a “drier” flapping sound in the thinner air, only experienced with the sight of mountains above the tree line, making another anomaly in your mind.
- In case of power plant failure, autorotation from 8000ft gives you almost 5 minutes of autorotation glide time, and a possible landing spot up to 6 or 7 miles away.
- In case of a catastrophic failure, a body in free fall will reach maximum vertical velocity in 1500ft, so 200ft might be better chance to arrive there slower and maybe right side up, especially if that failure is developing in the next 10sec, with heavy vibration and all those high emergency signs...

When doing visual power line checks there is (at least in Europe) a power line expert observer onboard. The flying technique typically involves heavy side silps to offer the observer the best view and more time to inspect every pole and its insulators.

I have heard said that the older a helicopter pilots gets the lower they fly.

I have done those 10,000 foot cruises seeking some cooler air in the tropics and at the same time have been quite content to do the same trip at 300 feet.

There is no doubt you can see more low than you can high especially if scouting for Elk and Black Bear with an approaching hunting season coming up.

Reading railroad, highway, and water tower markings is far easier from 300 feet than 10,000 feet.

As to malfunctions at height....once had an abrupt engine failure at about 9,000 feet AGL....it still seemed like mere seconds before landing.

I know in my heart that is way too high for such things as it affords you far too much time to think....as helicopter pilots and with too much time to think often leads to trouble.

The rare event of a major cast iron failure such as a Main Transmission or Rotor head catastrophic failure....the odds are not much different if you are at 10K or 300 feet except for the fact you might live just a bit longer from way up high but I doubt the quality of that extended life would be much improved over the short duration from the lower height.

If you dwell upon such things perhaps helicopter flying is not your best choice of careers.

My instructor was a 4000 hour pilot, about half in the OH6 with service in Vietnam and the rest civilian. We were doing a night XC and had departed KGBR. As I climbed through 4000' to get a comfortable height over the hills (for me) in the black hole, he shines his light over to the altimeter and asks how high I'm going. Then says "you are scaring me! I've never been this high." He was probably kidding.

The highest I've flown in a helicopter was 14,000 feet. The task was hovering over a spot, at night, on instruments. The ground elevation was less than 500 feet. Surreal, but you do get used to it, mainly because it takes so much concentration to do it.

Just about every flight test program I've been on where we had to go up to 15,000 ft, the pilot (not the DER test pilot) has pulled out their cellphone to take pictures of their altimeter. One of them still has it up on Instagram.

17000' in a Huey, over Mt Wilhelm in PNG.

Vne was 55kt, min flying speed was 48kt, not a lot of latitude there. Rolling the throttle off for an auto meant that the collective was up under the armpit to control RRPM.

First helo experience was short-term S&R in K'sar detached from fixed-wing Valettas. Helos were Sycamores and did a 10,000 height climb which was nice and cold and no problem. When I later went full-time S&R on Whirlwinds, "low is good - high is is uncomfortable" ! Fairly common trait ... my Boss (long -time rotary) said that when he had to do Whirlwind height climbs (10k), he had to imagine a large pair of swept wings attached to the rear of the cabin to make it more acceptable.

What is Min Flying Speed?
Never heard the term before.

Flying around low in normal operations purely in case of a transmission failure is not sound thinking in my view. That's like not going outside just in case you get struck by lightning.
Do it when you have to for a valid reason, otherwise operate at a safe and sensible height. Less birds and wires, better radio comms, a bit more time to execute an emergency landing. Of all the emergencies one can have, it's only a very small percentage where a few more seconds before landing would have made a difference, and in the case of a main transmission failure you are most likely dead no matter what height you are at.
Risk vs Gain is one equation to manage well in aviation.

Look at your Power Available Vs Power Required graph. PA line cuts through the PR curve in (usually) 2 places.

The one on the right is your max speed in level flight, the spot on the left is min speed, you must descend if you go slower. The higher you go, the PR curve moves up, and the PR line slides down. When it becomes a tangent, you only have one speed, but technically you can never reach that tangent as you need excess power to get there.

Yes, this was my approach while I was transitioning from fixed to rotorwing. From a long history of fixed wing flying, and usually flying so as to "have a place to go if...." higher was better. While I liked that little bit of extra space/room/altitude, my instructors kept telling me to go lower, get in closer. I felt a balance of risk v benefit for training. Sure, if you have to get someone off a mountain side, get in close, and I guess you have to train for that - I did. But, and as I explained to my instructors, I would have a hard time justifying not leaving myself a decent "out" for simple training.

On the other hand, and I have discussed it with certification authorities more than once, the phrase "land immediately" in the context of an emergency procedure is a little mis guiding. When you tell a pilot to "land" an aircraft, pilots tend to first look for a place where they could put the machine down, and hopefully be able to reuse it the next day. There have been cases where that delay in simply crashing it straight ahead was fatal. I think of the Cougar Helicopters S-92 off Newfoundland. Warnings were indicating that a "land immediately" was the appropriate action. Yet the pilots remained hundreds of feet up - maybe trying to make it to a better place. They should have been down on the deck ASAP - splash here under control, or splash up ahead not in control? Easy decision.

Many of my autorotations, particularity when flight testing something, have been from thousands of feet up, and been pleasing. You get into a very stable regime of gliding flight, and can actually take a few moments to feel what the helicopter is doing, and assess things. Aside from training, I've never needed to enter a low altitude autorotation, other than from the hover, but can appreciate an auto in which "it just all happens".

I do recall a pleasing flight I was given in a two place autogyro. I did notice that the primary instrument was the rotor bearing temperature!

Many examiners I know have made sure, it is not. My check ride, we discussed the emergency procedures: "chip light with vibration what do you do?" I said "land immediatly!" he said "what does that mean?" I said "right here! pointing at a spot below my instrument panel" he was happy and moved on.

I would guess power line inspection also because I have major powerlines running nearby and once witnessed what looked like an early Cessna 170 / O-1 Bird Dog flying erratically 200 to 300 feet up, following the powerlines and it was so wobbly and all over the place I thought the pilot was drunk. It was like something out of a movie. They did laps, back and forth and checking the flight radar revealed their tracks and it all made sense. Was very exciting to run out when it was coming back and spotting it again!