Narrative:

This was a helicopter training flight for the purpose of reviewing hovering autorotations. I was the CFI. The student had about 30 hours in helicopters. This was the second lesson on hovering autos in this particular helicopter. The student had several previous lessons on hovering autos in a different make of helicopter and had become proficient. We had been doing hovering work including hovering autos for about 40 mins. All of the hovering autos were entered at about 2 ft AGL. The student had just demonstrated several successful hovering autos. On the last hovering automatic, the student shoved the cyclic extremely far forward, unexpectedly. This created a dangerous nose low attitude. To prevent hitting the ground in this attitude, I immediately pulled in all available collective, leveled the aircraft and stopped all drift. In doing this, all of the rotor inertia was used to correct the attitude. The helicopter then dropped 18-24 inches straight to the ground with no inertia available for cushioning the landing. This resulted in bending the front and rear cross tubes of the skids/landing gear. After a thorough inspection, no other damage was noted. My perception of the landing was that it was not that hard of impact. While it clearly was sufficient to bend the cross tubes, I can't help but think that this landing was just the final straw. I had noted some curve to the rear cross tube during previous preflts, but considered it to be normal. This particular helicopter has about 1300 hours on it. The cause of this incident was clearly my failure to guard the controls. The student had just done 2 consecutive smooth hovering autos without assistance. This factor combined with the fact that the student is almost ready to solo, caused me to not guard the controls closely. In analyzing my response to this situation, I am not sure what I would have done differently. I believe that the helicopter would have rolled over if we hit the ground in the nose low attitude. My thoughts were to get the helicopter level and stopped. A possible contributing factor may have been the student's large amount of airplane flight experience. The student is an asel and amel CFI, as well as a cfii. His reaction to the low rotor warning horn seemed similar to a proper reaction to an airplane stall warning horn, shove forward on the controls. The 2 different warning system do sound similar.

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Original NASA ASRS Text

Title: A STUDENT AND INSTRUCTOR IN AN H1P TOUCH DOWN HARD ENOUGH TO BEND THE CROSS TUBES OF THE LNDG SKIDS. NO INJURIES.

Narrative: THIS WAS A HELI TRAINING FLT FOR THE PURPOSE OF REVIEWING HOVERING AUTOROTATIONS. I WAS THE CFI. THE STUDENT HAD ABOUT 30 HRS IN HELIS. THIS WAS THE SECOND LESSON ON HOVERING AUTOS IN THIS PARTICULAR HELI. THE STUDENT HAD SEVERAL PREVIOUS LESSONS ON HOVERING AUTOS IN A DIFFERENT MAKE OF HELI AND HAD BECOME PROFICIENT. WE HAD BEEN DOING HOVERING WORK INCLUDING HOVERING AUTOS FOR ABOUT 40 MINS. ALL OF THE HOVERING AUTOS WERE ENTERED AT ABOUT 2 FT AGL. THE STUDENT HAD JUST DEMONSTRATED SEVERAL SUCCESSFUL HOVERING AUTOS. ON THE LAST HOVERING AUTO, THE STUDENT SHOVED THE CYCLIC EXTREMELY FAR FORWARD, UNEXPECTEDLY. THIS CREATED A DANGEROUS NOSE LOW ATTITUDE. TO PREVENT HITTING THE GND IN THIS ATTITUDE, I IMMEDIATELY PULLED IN ALL AVAILABLE COLLECTIVE, LEVELED THE ACFT AND STOPPED ALL DRIFT. IN DOING THIS, ALL OF THE ROTOR INERTIA WAS USED TO CORRECT THE ATTITUDE. THE HELI THEN DROPPED 18-24 INCHES STRAIGHT TO THE GND WITH NO INERTIA AVAILABLE FOR CUSHIONING THE LNDG. THIS RESULTED IN BENDING THE FRONT AND REAR CROSS TUBES OF THE SKIDS/LNDG GEAR. AFTER A THOROUGH INSPECTION, NO OTHER DAMAGE WAS NOTED. MY PERCEPTION OF THE LNDG WAS THAT IT WAS NOT THAT HARD OF IMPACT. WHILE IT CLRLY WAS SUFFICIENT TO BEND THE CROSS TUBES, I CAN'T HELP BUT THINK THAT THIS LNDG WAS JUST THE FINAL STRAW. I HAD NOTED SOME CURVE TO THE REAR CROSS TUBE DURING PREVIOUS PREFLTS, BUT CONSIDERED IT TO BE NORMAL. THIS PARTICULAR HELI HAS ABOUT 1300 HRS ON IT. THE CAUSE OF THIS INCIDENT WAS CLRLY MY FAILURE TO GUARD THE CTLS. THE STUDENT HAD JUST DONE 2 CONSECUTIVE SMOOTH HOVERING AUTOS WITHOUT ASSISTANCE. THIS FACTOR COMBINED WITH THE FACT THAT THE STUDENT IS ALMOST READY TO SOLO, CAUSED ME TO NOT GUARD THE CTLS CLOSELY. IN ANALYZING MY RESPONSE TO THIS SIT, I AM NOT SURE WHAT I WOULD HAVE DONE DIFFERENTLY. I BELIEVE THAT THE HELI WOULD HAVE ROLLED OVER IF WE HIT THE GND IN THE NOSE LOW ATTITUDE. MY THOUGHTS WERE TO GET THE HELI LEVEL AND STOPPED. A POSSIBLE CONTRIBUTING FACTOR MAY HAVE BEEN THE STUDENT'S LARGE AMOUNT OF AIRPLANE FLT EXPERIENCE. THE STUDENT IS AN ASEL AND AMEL CFI, AS WELL AS A CFII. HIS REACTION TO THE LOW ROTOR WARNING HORN SEEMED SIMILAR TO A PROPER REACTION TO AN AIRPLANE STALL WARNING HORN, SHOVE FORWARD ON THE CTLS. THE 2 DIFFERENT WARNING SYS DO SOUND SIMILAR.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.