What was found
EXPERIENCED A LT YAW AND LOUD HOWLING/GRINDING SOUND FROM TRANSMISSION. NO CAUTION, ADVISORY, OR WARNING LIGHTS. LOWERED COLLECTIVE TO UNLOAD TRANSMISSION AND TO KEEP AUTO AIRSPEED, LOUD HOWL PERSISTED. LANDED.
- Difficulty date
- April 14, 2012
- Submitted
- July 26, 2013
- Operation
- Air carrier
- Aircraft
- N509MT
- Make and model
- Bell 407
- Aircraft serial
- 53281
- Aircraft time
- 7,379 hours, 22,114 cycles
- Engine
- Allsn 250C47B
- Engine time
- 3,118 hours, 8,058 cycles
- System (JASC)
- 7250 · Turbine Section
- Part
- Turbine Wheel
- Part number
- 6898663
- Part serial
- X589849
- Condition
- Failed
- Location
- Engine
- Part time
- 1,098 hours, 2,030 cycles
- Stage of operation
- CR
- How discovered
- O
- Nature of condition
- F, T
- Precautionary procedure
- E, A
As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.