407D, you should know the answer to this one - what''s the story on the US Forest Service recently prohibiting the use of the 407 for their ops - here is an exerpt:
No. 2003-08 May 22, 2003 Page 1 of 2
Subject: Bell 407 Helicopter Stand Down
Area of Concern: Helicopter Operations
Distribution: USFS Aviation Operations
Discussion: Recently, Bell 407 helicopters have experienced a series of accidents resulting from power losses. One of the accidents occurred while the USDA Forest Service (FS) was supporting the NASA space shuttle recovery efforts in Texas. The FS has decided to issue an immediate stand down of exclusive use and call-when-needed contract Bell 407 helicopters.
The Bell 407 is equipped with a Full authority Digital Engine Control (FADEC) system. It is designed to enhance flight safety and reduce pilot workload. There are two main components to the system, the Electronic Control Unit (ECU) and the Hydromechanical Unit (HMU). Also, there is a Permanent Magnet Alternator (PMA), which provides electrical power to the ECU and its components.
The Bell 407 is equipped with Rolls-Royce Model 250-C47 B engine. Rolls-Royce has published four (4) Commercial Engine Bulletins (CEB) concerning the inspection/replacement of ECU/HMU components. These CEBs are identified as follows:
Engine, Fuel and Control – On Time inspection of Power Lever Angle (PLA) Signal of the HMU CEB-A-73-6040 May 8, 2003.
Engine, Fuel and Control – Release of New Electronic control Unit (ECU) CEB-73-6036 March 17, 2003.
Engine, Fuel and Control – Hydromechanical Unit (HMU) –Incorporate screened P1 Nozzle CEB-73-6039 July 31, 2002.
Engine, Fuel and Control – Inspection of HMU Drive Splines CEB-A-73-6030 November 6, 1998.
In light of the recent CEBs and accidents; aviation safety, contracting, and program managers representing DOI and USFS held a conference call on May 21, 2003 to discuss safety concerns involved with the Bell 407.
Since the Forest Service and DOI often operate over hazardous terrain and in mission profiles that afford limited response time in the event of a power loss, it was the unanimous agreement of the conferees that the FS should immediately suspend the use of all Bell 407 helicopters in ALL Land Resource Management activities.
Once vendors of Call-When-Needed and Exclusive Use contracted helicopters have completed all applicable inspection/overhall/replacement of components identified in the CEBs, the contractor should send the documentation to the appropriate FS maintenance inspector for examination.
The FS suspension of Bell 407 helicopters will remain in effect until a return to contract availability is issued.
Here is the FAA blurp:
http://www.ntsb.gov/Recs/letters/2003/A03_18_21.pdf
