Purpose
To simulate landing the aircraft in the event of a complete loss of power
Description
- Demonstrate the glide portion of an autorotation.
- Allow the student to develop an understanding of how pitch and collective setting affect RPMs.
- Demonstrate flare and power recovery procdures.
- Allow the student to practice the power recovery procedure at altitude.
- Allow the student to practice the flare and power recovery procedures.
- Allow the student to practice the entire procedure, from entry to power recovery.
Instructional aids and pre-requisites
- Ground Lesson pre-requisites: Emergency Procedures, Robinson R22 Safety Notices, Aerodynamics
- Lessons PS-1 and PS-2 are pre-requisites
Content
- Pre-flight briefing: Review the relationship between collective setting and attitude to RPMs
| Aft Cyclic | No Change | Forward Cyclic | |
| Up Collective | Dec AS | Dec RPM and Dec RoD | Lg Dec RPMs |
| No Change | Inc RPM, Inc RoD | — | Dec RPM, Dec RoD |
| Down Collective | Lg Inc RPM | Inc RPM, Inc RoD | Inc AS |
- Pre-flight briefing: Discuss procedure for preparing for an autorotation
- Pre-landing checks, area clear, landing area clear, 3-count to enter
- Pre-flight briefing: Student should be prepared for the high rate-of-descent that accompanies an autorotation, and should be confident that the instructor can recover from a low rotor RPM condition
- From level flight at 70 kias, 2000-3000΄ agl and headed into the wind, enter an autorotation and establish a glide at 60-70 kias
- Have the student focus on developing a scan (attitude, trim, RPMs, airspeed)
- Demonstrate the effect of collective and attitude changes, and how collective setting does not need to be changed if attitude is held constant
- Repeat the autorotation and allow the student to control the cyclic and collective during the glide (instructor enters and recovers from the autorotation)
- Demonstrate the power recovery procedure at the termination of the glide, and allow student to practice the power recovery at altitude and without distraction from the landing area
- Once the student is comfortable with RPM control and can perform a VFR scan during the autorotation, allow the student to perform a glide with power recovery at altitude
- Once the student is comfortable with the glide and power recovery portions of the autorotation, demonstrate a normal flare and power recovery
- Introduce decision point checks: at 100-200 ΄ AGL, check RPM in the green, airspeed stabilized between 60 and 70 kias, and rate-of-descent <1500 fpm
- Maintain alignment with ground track below 100 ΄ agl
- At approximately 40 ΄ agl, begin flare with aft cyclic to reduce rate-of-descent and airspeed (amount of flare will vary with wind conditions, gross weight, and density altitude: adjust so that rate-of-descent and airspeed can be decreased without ballooning)
- At 8-10 ΄ agl, add throttle so that RPMs are in the lower green range
- Level the aircraft with forward cyclic
- As the aircraft reaches a level attitude, add collective (and throttle, if necessary) to attain a hover at 5-10 ΄ agl; maintain trim with left pedal
- Avoid a nose-high attitude below 10 ΄ agl, and arrive at a hover above 5 ΄ agl
- Repeat the autorotation and allow the student to perform the glide, flare, and power recovery (instructor performs the entry)
- Once the student is comfortable with the glide, flare, and power recovery portions of the autorotation, allow the student to enter the autorotation
- From level flight at 70 kias, 700΄ agl and headed into the wind, clear the area, perform pre-landing check, and identify touchdown location
- When aircraft is aligned with touchdown location, enter an autorotation by smoothly lowering the collective to full down and maintain trim with right pedal
- Reduce throttle to split the needles, and add aft cyclic to a 60-knot attitude
- Adjust cyclic to maintain 65 kias and collective so that RPMs are in the green
- Continue with the glide, flare, and power recovery
Common errors
- Airspeed and RPM deviations during glide
- Have student call out scan elements, and point out deviations
- Perform autorotations away from distractions (eg, traffic on the surface or in pattern) and, initially, without specifying a touchdown spot
- Emphasize the importance of maintaining the correct attitude
- Rushing the entry can set the student up for problems during the glide: before the autorotation, have focus on the horizon, and encourage a slow and deliberate entry
- Initiating the flare too high/too low
- Use a progressive flare that starts gently and increases as they approach the ground
- Introduce quick stops (Lesson AM-6) so that student can develop the correct sight picture for the same altitude where the flare is initiated
- Difficulty during the power recovery
- Control coordination is essential and requires practice
- Initiate a smooth, slow increase in throttle early in the flare
- Overshoot/undershoot landing spot
- Initially the instructor should prompt the student to initiate the autorotation, allowing the student to develop a windscreen reference for alignment with the landing spot
Completion standards
- Pre-determined spot ±50 ΄
- RPM maintained within the green range (101-104%)
- Airspeed 60-75 kias
Teaching considerations
- Instructor should set personal limits for practice autorotations; if limits are not met at any time during the procedure, terminate and recover
- Limit practice autorotations to 3 or 4 consecutive attempts
- Allow the student to fully understand the effect of control inputs during the glide before progressing to other stages
- Fix problems/deviations immediately or terminate the manuever
- Consider true airspeed if high denstity altitude
- When practicing maximum glide or minimum rate-of-descent, adjust RPM setting for density altitude (+1% per 1000΄)
Videos on how to perform autorotations
httpvh://www.youtube.com/watch?v=WyNgCKErIoY httpvh://www.youtube.com/watch?v=cajc9kDmb6o
Additional practice
- Additional practice: Practice entry from various altitudes, airspeeds, and at different gross weights
- Additional practice: Maximum glide configuration
- Adjust attitude for 75 kias
- Adjust collective for rotor RPMs at 90%
- Below 500 agl, adjust attitude for 65 kias and collective so that RPMs are in the green range
- Additional practice: Air restart procedure
- During glide portion, practice procedure for attempting an air restart
- Additional practice: Minimum descent rate configuration
- Adjust attitude for 53 kias
- Adjust collective for rotor RPMs at 90%
- Below 500 agl, adjust attitude for 65 kias and collective so that RPMs are in the green range
Real-Life Experience
It has been my experience that the vast majority of engine failures in piston or turbine are very seldom a castrophic immediate stoppage. Rather they are presaged by some form of warning such as in the engine instruments, an unusual vibration or noise, or a decrease in rpms. Even running out of fuel doesn’t stop the engine as fast as a throttle chop. Some helicopters (piston) are prone to quit on ya with a chop and you are going to make a touchdown auto like it or not. I learned a long time ago if you are going to practice an autorotation you better expect it to go to a full down just in case. Never bent one yet (the aviation Gods must like me and blessed me with a full load of luck!) and not all were to a nice prepared area. As for counting down to an auto entry, it is fine with a low timer for initial training but after that I think it can cause problems later on. As was pointed out, you won’t often get the countdown for an actual and if you are trained to go on a countdown, you may find yourself way behind events with a real one. Your mileage may vary.
Additional resources
- Helicopter Concepts Video