As stated earlier, this check has not changed since I've been an OH-58D MTP and, as far as I know, it's the same check used since they first started building the OH-58D. However, the method of training for this maneuver has changed for students going through the MTPC. The Directorate of Evaluation and Standardization has some key safety points for every MTP we work with at Fort Rucker or when we are visiting units in the field. There have been three Class A accidents in recent years related to this check. If you are an OH-58D MTP, please take the following advice to heart.
When discussing this maneuver, we like to tell the test pilots to set themselves up for success. What this means is to plan for the worst during the check. Do not assume the engine is going to come back to life at the bottom of the autorotation just like it has hundreds of times before. I will be the first to admit that during my time as a junior MTP, I made that assumption. I can recall making the cross-country flight from Fort Carson, Colo., to the National Training Center at Fort Irwin, Calif., where we knew we would have to make an autorotation RPM adjustment due to the decrease in altitude. Before arriving at Bicycle Lake, we climbed over the Mojave Desert and rolled off the throttle to take the measurement. Fortunately, the engine always responded and I didn't have to attempt a successful touchdown autorotation to the desert floor.
Other than my own personal lack of experience at that time, the only excuse I can make is I was trained to do the check that way. Up until recently, the OH-58D MTPC had always trained this maneuver to two grass strips in the south maintenance test flight area on Fort Rucker. This maneuver is now trained in the traffic pattern at Dothan Regional Airport so the student pilot can align the aircraft with an actual runway. Here's your first piece of advice: Conduct this maneuver only where a touchdown can be made to an improved landing area, if necessary.
The second piece of advice goes out to the currently deployed MTPs. This one deals with the weight of the aircraft at the time of the maneuver. Set yourself up for success by reducing the weight of the aircraft as much as possible before you do this check. That means taking the rockets out of the launcher, removing the Hellfire missiles or pulling that ammo can full of .50 cal. Remember also that 300 pounds of fuel weighs the same as 300 pounds of ammo. If you are conducting a general maintenance test flight, try to save this check for last so you are as light as possible when you do it. To give you some perspective, the "Slick" aircraft used for contact training at Fort Rucker weighs between 4,500 and 4,600 pounds with a full bag of fuel. Touchdown autos are conducted day-in and day-out on these aircraft without incident. The closer you can get to that weight, the better your chances are at surviving an engine failure.
The third and final piece of advice deals with heeding the second warning associated with this check. This requires the MTP to select an entry altitude that allows a power recovery by 500 feet above ground level. The reason for this warning should be obvious in that it gives the MTP time to plan an autorotation to the ground in the event of an actual engine failure. It could also apply to a mistake if the MTP forgot to roll the throttle back on before increasing collective to establish a climb. The "Throttle Warning" message will display at 400 feet AGL if the throttle is below 92 percent throttle position. However, the MTP's first warning indication will most likely be the LOW ROTOR audio when attempting to add power to establish the climb prior to 500 feet AGL. Regardless, adhering to the warning will give you the time you need to either fix the mistake or conduct a successful touchdown auto.
Applying these three simple steps may someday keep you from damaging an aircraft beyond repair or even save your life. This should be the goal of every pilot. As many of you know, Corpus Christi Army Depot, Texas, is in the process of building more OH-58D helicopters. Unfortunately, we continue to destroy them faster than they can repopulate the fleet. One last thing, even if you are not an OH-58D MTP, this advice still applies to all aviators conducting any type of power-off maneuver. Stay safe!

Page last updated Tue January 3rd, 2012 at 00:00