I have a couple of questions for you Kevin. My choice of words may appear blunt but that is mainly due to my lazyness. I am an experienced GA pilot, I have not flown transport (>5700kg) aircraft. I have only formally completed the required ground school as per the CAA examination as I progress to my commercial career. So any real-world infor would be welcome:Maybe a bad choice of words on your part, but how can trim increase elevator authority? If anything, with a normal setup, it reduces it. Your idea of a sabilator is not the same as mine: The design of the stabilator or variable incidence tail (VIT), as I know it.One of the design features of the VIT is that trim settings do not impinge on the elevator effectiveness because when trimmed, the evelevator will be in the neutral position. Also trim drag is vastly reduced. Also, for transonic speeds, the VIT is used as a mach trimmer to pevent the so called mach 'stall'. Please explain your system.Can you give me an example of such an aircraft? Transport aircraft, as I understand them, are usually hydraulic with Q-feel systems to help prevent overstress or electro-hydraulic with digital control laws. I could see no reason why you would have such problems with elevator effectiveness unless the Q-feel system kicking in and increasing the required stick loads.This is a question due to ignorance: Also, when does an ATPL get the opportunity to do steep turns. I've never come across a SOP that permitted anything more than 25deg (I believe max is 30deg in the US I believe) bank for normal ops. I thought play time was for the sim or for test pilots!

I fly the EMB-145. It has an all-moving stabilator with an elevator attached to it. The stabilator is actuated by an electric trim system while the elevator is completely manual. The range of indicated airspeeds in which this plane flies can vary between 100kts to 320kts. At a low airspeed like 130kts, if your trim setting was at a something low, say like 0 units, you would not be able to keep the nose attitude level, it would fall through despite pulling the elevator all the way back. A trim setting like that is for cruise speed, and the plane will seek that speed, one way or another, a full back pull on the yoke is not going to win the argument. Unless you trimmed the stabilator up, the tailplane will not provide enough downforce on the tail to bring the nose up to where you want it to be. If I tried to takeoff with a too low trim setting, I would never be able to rotate the plane off the ground and I would go careening off the end of the runway with the yoke in my gut. This has happened to many a jet. I think the Challenger that went off the runway at TEB recently was due to a wrong trim setting. The stabilator is just like the tailerons on planes like the F-15 or F-16, it provides the necessary pitch authority by movement of the entire surface. Our manual describes the tail as "...the same effect as having an all-moveable tail (stabilator); but permits the Pilot use of the elevator to make small corrections from the established trim setting for a short period of time". The elevator on the E145 is described as having 30% of the plane's pitch authority.A few years back, an American Eagle crew stalled out their Horizontal Stabilator Control Unit during takeoff, basically inoperating their stablilator trim and leaving it stuck at a takeoff trim (7-8 units). They could not control the airplane. The radar track looked like 3-D spaghetti noodles in the sky...over O'Hare. Planes were scattering all over the sky to get away from them. Fortunately, they managed to yo-yo the plane back down onto the ground after about 20 minutes of practically uncontrolled flight over Chicago.The day before I wrote that reply, I was actually doing steep turns and stalls in the E145, albeit in the sim, during my 6 month proficiency check. We do 45 degree banked turns and we do clean, takeoff and landing config stalls, just like your basic student pilot. In all those maneuvers, you trim throughout, or else the maneuver gets ugly. In the stalls, unless you trim it, you will not be able to keep the plane from descending as the speed bleeds off. This is of course unacceptable since our tolerance is +/-100' altitude in the stalls. We trim all the way down to 130kts (@8units), per our manual, any more up trim than that puts the maneuver at risk of getting ugly with a balloon up during the recovery phase. As we slow through 130kts, the rest of the maneuver is focused on controlling the pitch with the elevator until shaker activation. At that point, I usually have the yoke very close to my gut, and my speed is probably around 110kts, but I'm not sure though since my attention is primarily focused on the AOA indicator at that point. But if I did not trim the plane from our maneuver starting point of 200kts (@4units), I would not be able to hold altitude since the tail would not provide enough aerodynamic downforce at 130kts at that incidence to keep the nose up despite full up elevator.The elevator authority is what it is...what trimming does is provide that authority for the present conditions. If you fly a jet like this out of trim, then what is happening is that you are squandering part of your elevator authority in trying to compensate for the stabilators' inappropriate position...which means a loss of pitch authority for any other maneuvering you want to do.Sorry for the delay in reply, I was out flying a trip.

I appreciate the fantastic reply Kevin! It is good to get a more real account of operational difficulties rather than the dry and theoretical ATPL syllabus.Thanks again :)