I instruct in the TH-57 - very similar to the "news helicopters" of the 80s and 90s. Carries 5 people, two blades, skids to land on. We use it because it's cheap, reliable, easy to fix, has readily available parts, etc. etc. Considering all we put the birds through, it's a beast. For example, on any given day a bird may have its engine cut to idle in flight, float to the ground, and then run the engine back up to full speed, for anywhere between five to ten or more times. Point being, we run the birds into the ground, but they're designed for it, so they perform admirably.
Overtorques are a very notable exception. You see, we have a very capable engine that gives us about 420 shaft horsepower, but a transmission that is only rated to 317 shaft horsepower.
What a TH-57 may look like.
We also have a "droop compensation system" that responds at a rate commensurate with the rate at which you move the collective. (The collective controls the pitch on the blades - more pitch = more thrust = needs more engine power.) All of these things along with student jitters combine to create the overtorque. We're normally allowed to go to 100% torque, with a 10-second allowance up to 110%. Above that, you have to land the aircraft to get trucked back due to the fact that you may have damaged the drive train - and the aircraft doesn't fly for very long when disconnected from the engine.
Overtorques happen for many reasons - an improper pedal turn, bringing the engine online from idle while still applying pitch to the rotors, or, in my case the other day, a very quick increase in collective. Instructors are given guidance to defensively posture themselves to avoid overtorques, to include advising you to place your hand over the collective to limit its travel when you think the student is about to increase it for whatever reason. In my case, my student looked to end an approach early due to being in a bad place to make a safe landing. He began to increase collective quickly and I wasn't in a good position to stop its travel and DING! We hit 118%. My first overtorque.
(for those wondering what "ringing the bell" is, it refers to the quickness with which the torquemeter's needle moves - and when it gets to 110% or more, the digital display flashes at you. DING DING DING DING DING)
Weather was skosh while driving in, but we briefed anyway in anticipation of the clouds lifting later in the afternoon. After briefing I saw a lot of red CNX WX up on the ops board and my studs were giving me a bit of pressure to cancel. I had a feeling that we just needed to give the weather a bit more time, so I said we'd sit for a while and see how the cloud decks turned out. Sure enough, in an hour and a half we had enough sky to go flying for a couple of BI flights.
I was a bit nervous, as this was my first flight with students and I was the first guy from my squadron to launch and go fly BIs, which have a different set of weather requirements than all our other flights. After going through checklists that seemed to take twice as long as usual we got out to the working area - weather was juuuuust good enough to complete all our maneuvers. Not bad for a first flight. To top it off, the lineman gave us a ride back to the hangar!
I didn't really anticipate the extent of weather and ops-related delays in getting started with students, but here I am - 2 weeks in, not quite ready for prime time and still one IP/IP flight left. Although I'm hoping to have my first students on Tuesday or Wednesday, I'm not terribly concerned about it. Hell, in my free time since checking in, I've installed a surround sound system into the ready room, designed a bamboo overhang for the bar. Just trying to keep busy.
Got to the squadron around 8:15 - brief was at 8:45. Had to ask a couple people where all the stupid preflight planning stuff was, like a weight and balance form and the grade cards, which took up some of my extra time, but I still made it to the skipper's office in time for the brief - at which time he said "Great, Herbie, go grab us a briefing space." (usually you brief in the skipper's office in my experience, but whatever, he's the man.) I grabbed a space, put the discuss items up on the board and waited. He came in, I stood up and we shook hands and then got down to business. We didn't cover much more than the ORM brief items (which were one of the discuss items) in the brief, but it was good anyway - lots of sea stories.
We met on the back porch, looked at the ADB, walked to the aircraft, started up and got going. It was a bit weird to be running the checklist vice actually doing it, but that's what the skipper wants, so that's what he gets! The weather was GORGEOUS - a few clouds way, way, up there, good winds of 8-10 knots, sunshine and about 65 degrees. You can't ask for a better day to go flying.
We got out to the working area and began to go through simulated emergencies at altitude, including engine failures. I demo'd the first engine failure, talking all the way through it and then the skipper took the controls and acted like he was a typical dumb student flying the engine failure. (We simulate those by reducing the engine throttle control to flight idle and then using the kinetic energy stored in the rotating blades to autorotate downward.) I rolled off the twist grip (throttle) and he started going through the procedures, acting like a student and making typical student errors. I corrected him, took the controls and waved off the approach, and we set up to head into Pace (an outlying field or OLF).
At Pace we started easily with a normal approach to a a hover and a vertical landing with me talking my way all the way around the pattern and onto the deck, just as if I was with a student. The skipper then did the same thing, acting as a student and gauging my responses. I suppose I should add that this flight was my first time acting as an instructor, even though I was flying with the CO, so I don't really have my techniques locked down just yet, but I'm told that this will come with time. Skipper did nothing terribly crazy - just some shady ball control and confusion over the appropriate altitudes, but with some prompting from me it ended up okay.
After that we did some maneuvers for my proficiency, then steep approaches to a no-hover landing for both me and the skipper-acting-as-student. That was a bit more squirrely, since the procedures are just different enough to confuse students - and when you don't know what's going on, you usually revert back to a previously learned yet similar behavior - in this case, a normal approach. But other than that and getting caught up in a low hover vice a no-hover landing, everything was reasonably good.
From there we went to power-off maneuvers. These are cut guns, taxi cut guns, and autos. Cut guns happen when the instructor (me) rolls the twist grip off while in a hover. I did one in order to gain proficiency for me and additionally to see how the aircraft is going to respond to the power off maneuver. After completing one, I transferred control to the skipper, who did one for his proficiency. We didn't go "fight's on" (skipper simulating a student) for cut guns and taxi cut guns due to their unforgiving nature, but did so for the autos. We finished up with some taxi cut guns, which are cut guns while taxiing forward, and proceeded to the auto pattern. After completing a couple of 90- and 180-degree autos, we went "fight's on" and the skipper started simulating a student again, forgetting to roll off the twist grip for one auto and getting sloppy with ball and Nr control on the second. The second also saw him neglecting to bring the twist grip back to full open at the appropriate altitude, resulting in me taking the controls and rolling it on while executing a waveoff. Not quite a low Nr recovery, but kinda close to it.
After that I did one more 180 auto for my proficiency and NAILED it - it was probably the best auto I've shot in a Charlie - and then we departed and headed home via course rules. After the flight and post-flight the skipper walked me through TIMS (our flight recording and grading system) and simultaneously debriefed me on the flight. Everything went well and he especially liked my verbal procedures and explanations of all the maneuvers and encouraged me to keep up the effort. After turning in our radios I went to talk to another instructor about something while he said that he'd "see me around campus" and headed back to the squadron.
