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Nov
18
2019

Segmented Autorotation…When More Than One Turn Is Needed

Posted 19 days ago ago by RandyRowles     0 Comments
RandyRowles

While conducting a Private Pilot examination, the applicant advised me that a segmented autorotative descent would be conducted in lieu of a constant radius turn during the 180-degree autorotation maneuver. The reasoning for the applicant’s decision was a set of small towers in the middle of the airport and a more segmented profile would eliminate the issue. The applicant executed the maneuver with a high degree of skill. It was a beautiful thing!

Accident data shows that autorotation training is the maneuver where many training accidents occur. More specifically, an autorotation with a turn leads the number of accidents for a single maneuver. The turning of the helicopter during the autorotation increases the rate of descent of the helicopter. Combine this with a distraction of a student, rotor RPM fluctuations, or even a bit of target fixation, and a high vertical velocity accident is a real threat. So, if a single turn provides challenge to the pilot during an autorotative descent, what happens when multiple turns are required to position the helicopter for a successful power-off landing?

A key component to any autorotation is the pilot maintaining a high and effective level of situational awareness. To do this, an accurate perception of the current state of the helicopter is required. Many factors may affect this perception to include experience, training, or simply a negative emotional response to the maneuver itself. One fact regarding perception is that only the individual can give meaning to what they perceive. Therefore, the building-block method of instruction for those intense and potentially emotionally draining maneuvers is important.

As the pilot navigates through all aspects of the autorotation, their comprehension of the constant state of change is difficult. Having a clear understanding of cause-and-effect of flight control manipulation will enhance the safety of the maneuver. In training, practicing autorotations at higher altitude increases the time available for the pilot to comprehend the situation. Higher altitude allows the pilot to complete an autorotation with a turn, and still have enough altitude remaining to identify and maneuver the helicopter to a safe landing.

In some situations, the helicopter may be too far from the preferred landing area to make a continuous turn. Periodically, the turn must be segmented. The pilot’s ability to quickly and accurately comprehend the situation when a segmented turn is required will enable more accurate projection and action; the final phase of situational awareness.

A segmented autorotation specifically refers to the entry and glide portions of the maneuver. A landing area that is too far away for a constant radius turn would be a candidate for a segmented approach.

The entry to an autorotation is a constant. The reduction of collective pitch combined with an aft cyclic input while maintaining trim of the aircraft is shared among most helicopters in our industry. Once the successful autorotative entry is accomplished, it’s game on! In the case of a segmented autorotation, the initial turn will not be to the preferred landing area. It will be to an intermediate point in the glide which will be the final turn to land. In lieu of a more standardized autorotation with a turn, this maneuver requires a straight-line extended-glide profile, only reconfiguring to a normal glide while turning on to the final approach of the maneuver.

This is a very complex maneuver and requires a high level of experience and situational awareness. The ability for a pilot to lose airspeed, increase their rate of descent, or even fixate on the approaching ground is real and very dangerous threat. Remember, the go-around decision point must be determined and vigilantly adhered to when performing any enhanced autorotation. Anything less is a crash looking for a place to happen!

About Randy: Randy Rowles has been a FAA pilot examiner for 20 years for all helicopter certificates and ratings. He holds a FAA Gold Seal Flight Instructor Certificate, NAFI Master Flight Instructor designation, and was the 2013 recipient of the HAI Flight Instructor of the Year Award. Rowles is currently the owner of the Helicopter Institute.




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