An small aircraft helicopter is developing lamination cracks in it's rotor blades at a faster rate t...

Narrative:

Blade rotation laminates showed signs of cracking/breakage. This condition is somewhat normal and well-addressed by manufacturer. Some cracking is allowed. Although laminates were still within published limits, it seemed to me that they were rapidly approaching an unservicable condition. I was concerned that due to the speed at which these cracks were occurring that we might not see the part go from merely 'unservicable' to 'dangerous.' after numerous discussions with management and manufacturer representatives, I came to the conclusion that my concern is largely unwarranted. However, some doubt remains as to the safety of operating a part that is approaching on svcability faster than generally expected. Solution: manufacturer should include some criteria in inspection manual for rate of deterioration, not just amount of deterioration, ie, one crack per 100 hours, etc. Callback conversation with reporter revealed the following information. The reporter, a and P mechanic with inspection authorization, states that he has filed an mmir (maintenance malfunction information report) with the FAA regarding the rate of deterioration of the blades on the helicopter for which he is responsible. His company has only one of this type of helicopter, but he has heard through the grapevine that other operators are having similar problems.

Original NASA ASRS Text

Title: AN SMA HELI IS DEVELOPING LAMINATION CRACKS IN IT'S ROTOR BLADES AT A FASTER RATE THAN THE MAINT SUPVR FEELS IS SAFE.

Narrative: BLADE ROTATION LAMINATES SHOWED SIGNS OF CRACKING/BREAKAGE. THIS CONDITION IS SOMEWHAT NORMAL AND WELL-ADDRESSED BY MANUFACTURER. SOME CRACKING IS ALLOWED. ALTHOUGH LAMINATES WERE STILL WITHIN PUBLISHED LIMITS, IT SEEMED TO ME THAT THEY WERE RAPIDLY APCHING AN UNSERVICABLE CONDITION. I WAS CONCERNED THAT DUE TO THE SPD AT WHICH THESE CRACKS WERE OCCURRING THAT WE MIGHT NOT SEE THE PART GO FROM MERELY 'UNSERVICABLE' TO 'DANGEROUS.' AFTER NUMEROUS DISCUSSIONS WITH MGMNT AND MANUFACTURER REPRESENTATIVES, I CAME TO THE CONCLUSION THAT MY CONCERN IS LARGELY UNWARRANTED. HOWEVER, SOME DOUBT REMAINS AS TO THE SAFETY OF OPERATING A PART THAT IS APCHING ON SVCABILITY FASTER THAN GENERALLY EXPECTED. SOLUTION: MANUFACTURER SHOULD INCLUDE SOME CRITERIA IN INSPECTION MANUAL FOR RATE OF DETERIORATION, NOT JUST AMOUNT OF DETERIORATION, IE, ONE CRACK PER 100 HRS, ETC. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO. THE RPTR, A AND P MECH WITH INSPECTION AUTHORIZATION, STATES THAT HE HAS FILED AN MMIR (MAINT MALFUNCTION INFO RPT) WITH THE FAA REGARDING THE RATE OF DETERIORATION OF THE BLADES ON THE HELI FOR WHICH HE IS RESPONSIBLE. HIS COMPANY HAS ONLY ONE OF THIS TYPE OF HELI, BUT HE HAS HEARD THROUGH THE GRAPEVINE THAT OTHER OPERATORS ARE HAVING SIMILAR PROBLEMS.

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.

Attributes
ACN	222638
Time
Date	199210
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : sjc
State Reference	CA
Altitude	agl bound lower : 0 agl bound upper : 0
Aircraft 1
Operator	common carrier : air taxi
Make Model Name	Helicopter
Flight Phase	ground : preflight
Flight Plan	None
Person 1
Affiliation	Other
Function	other personnel other
Qualification	other other : other
ASRS Report	222638
Events
Anomaly	other anomaly other
Independent Detector	other other : unspecified
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other
Situations
Publication	Unspecified

An small aircraft helicopter is developing lamination cracks in it's rotor blades at a faster rate than the maintenance supervisor feels is safe.