Narrative:

During final approach to landing zone, r-hand engine cowling exited aircraft striking main rotor blade and rear center main vertical stabilizer. The shattered cowling dropped to ground in pieces approximately 4 blocks nne of the landing zone causing no injuries or property damage. None of the onboard crew saw, felt or heard cowl leave the aircraft. 1 eyewitness on the ground observed pieces falling to the ground near local fire station. Incident occurred during landing phase of 40 min flight. Moderate to occasional to severe turbulence encountered shortly before incident. Callback conversation with reporter revealed the following information: reporter said that the turbulence they encountered really gave them a jolt. During the investigation, contact with the manufacturer's representative indicated that, if the cowling latches had not been properly secured, as a suggested sloppy preflight might have overlooked, the cowling would have departed the aircraft very early in the flight, rather than during the landing approach. The FAA seems satisfied that the incident was caused by aging cowling latches and considers the matter closed. Reporter believes that the manufacturer has notified all owners of the aerospatiale SA365 dauphin helicopter suggesting they inspect the involved latches carefully. Reporter added that this aircraft has a shrouded tail rotor, one enclosed by a part of the fuselage. The departed cowling struck this shroud and had it not been for the shroud, the tail rotor would have been destroyed with disastrous results.

Google
 

Original NASA ASRS Text

Title: DAUPHIN HELI ENG COWLING COMES LOOSE AND IS SHATTERED BY THE ROTOR BLADES DURING A LNDG APCH.

Narrative: DURING FINAL APCH TO LNDG ZONE, R-HAND ENG COWLING EXITED ACFT STRIKING MAIN ROTOR BLADE AND REAR CTR MAIN VERT STABILIZER. THE SHATTERED COWLING DROPPED TO GND IN PIECES APPROX 4 BLOCKS NNE OF THE LNDG ZONE CAUSING NO INJURIES OR PROPERTY DAMAGE. NONE OF THE ONBOARD CREW SAW, FELT OR HEARD COWL LEAVE THE ACFT. 1 EYEWITNESS ON THE GND OBSERVED PIECES FALLING TO THE GND NEAR LCL FIRE STATION. INCIDENT OCCURRED DURING LNDG PHASE OF 40 MIN FLT. MODERATE TO OCCASIONAL TO SEVERE TURB ENCOUNTERED SHORTLY BEFORE INCIDENT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR SAID THAT THE TURB THEY ENCOUNTERED REALLY GAVE THEM A JOLT. DURING THE INVESTIGATION, CONTACT WITH THE MANUFACTURER'S REPRESENTATIVE INDICATED THAT, IF THE COWLING LATCHES HAD NOT BEEN PROPERLY SECURED, AS A SUGGESTED SLOPPY PREFLT MIGHT HAVE OVERLOOKED, THE COWLING WOULD HAVE DEPARTED THE ACFT VERY EARLY IN THE FLT, RATHER THAN DURING THE LNDG APCH. THE FAA SEEMS SATISFIED THAT THE INCIDENT WAS CAUSED BY AGING COWLING LATCHES AND CONSIDERS THE MATTER CLOSED. RPTR BELIEVES THAT THE MANUFACTURER HAS NOTIFIED ALL OWNERS OF THE AEROSPATIALE SA365 DAUPHIN HELI SUGGESTING THEY INSPECT THE INVOLVED LATCHES CAREFULLY. RPTR ADDED THAT THIS ACFT HAS A SHROUDED TAIL ROTOR, ONE ENCLOSED BY A PART OF THE FUSELAGE. THE DEPARTED COWLING STRUCK THIS SHROUD AND HAD IT NOT BEEN FOR THE SHROUD, THE TAIL ROTOR WOULD HAVE BEEN DESTROYED WITH DISASTROUS RESULTS.

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.