Service difficulty report · Ditching Dam · Dhav DHC8301

Difficulty date
February 17, 2013
Submitted
September 14, 2015
Operation
General aviation
Make and model
Dhav DHC8301
Engine
Pwa PW123
Propeller
Rotol CR4086123F17
Part
Ditching Dam
Part number
82560034031
Condition
Unwanted Deploy
Location
Left
Part time
20,353 hours
Stage of operation
CR
How discovered
O
Nature of condition
D
Precautionary procedure
A

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

(CAN) LT DITCHING DAM DEPLOYED IN FLIGHT, INFLATABLE DAM, HOSE AND FITTING TORN AWAY. DAM COVER ASSY DAMAGED. LT DITCHING DAM ADAPTER ASSY DAMAGED AND REQUIRED NEW BURST DISK WITH DITCHING DAM WEB ASSY DAMAGED. LT DITCHING DAM WEB ASSY DAMAGED. INFLATABLE DAM, HOSE AND FITTING REPLACED WITH SERVICEABLE ITEMS IAW AMM 25-60-16 DAM COVER ASSY REPLACED WITH SERVICEABLE ITEM IAW AMM 25-60-16. ADAPTER REPLACED WITH SERVICEABLE ITEM AND NEW BURST DISK KIT FITTED IAW AMM 25-60-16. WEB ASSY REPLACED WITH SERVICEABLE ITEM IAW AMM 25-60-16 SYS NOW FULLY SERVICEABLE. OPERATOR HAS HAD ONE PREVIOUS INCIDENT MANY YEARS AGO AND THIS INCIDENT AS WELL AS THE PREVIOUS INCIDENT COULD HAVE BEEN CAUSED BY SOME COVER DAMAGE OR FOD OBJECT HITTING THE COVER. THE GAS BOTTLE AND BURST DISC WERE INTACT, INDICATING THAT THE SYS PRESSURE WAS NOT THE CAUSE OF THE DEPLOYMENT. IN OTHER WORDS THE DAM DID NOT INFLATE CAUSING THE DEPLOYMENT. SOME AIRFLOW DISRUPTION OR HAS ACTUATED THE COVER AND ALLOWED THE UN-INFLATED DAM ASSY INTO THE AIRFLOW CAUSEING IT TO IMPACT AND FLUTTER CAUSING SOME MINOR DAMAGE TO THE AIRFRAME IN THE IMMEDIATE AREA.