AD/BELL 206/158 Fuel Distribution System 8/2005DM

Applicability: Bell Helicopter Textron Canada (BHTC), Model 206 series helicopters as follows:

Model
206A
206B
Serial Numbers (S/N)
004 through 660 and 672 through 715
661 through 671 and 716 through 4586 and 5101 through 5305

Requirement: 1. Inspect the grounding of the fuel pumps and solenoid valve, as per instructions provided in Part I of Alert Service Bulletin (ASB) 206-05-103, dated 11 February 2005, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.

2. Disconnect and stow the fuel purge hose, as per instructions provided in Part II of ASB 206 05 103 or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.

Note 1. Model 206A S/N 004 through 253 complying with Service Letter No. 206A 100, dated 20 March 1969, which installs a purge line to the drain valve, must comply with Requirement 2 of this Directive. If the Service Letter is not incorporated, the rotorcraft is not affected by Requirement 2 of this Directive.

Note 2. Model 206A/B S/N 004 through 2123 complying with Technical Bulletin 206 85 113, meets the intent of Requirement 2 of this Directive since the purge line is disconnected from the drain valve and stowed as required.

Note 3. Model 206B S/N 2124 and subsequent, are not affected by Requirement 2 of this Directive.

Note 4: Transport Canada AD CF-2005-10 refers.

Compliance:For Requirement 1 - Within the next 100 hours time in service, but no later than 10 July 2005.

For Requirement 2 - At the first occasion when aircraft is defueled, but not later than 1 December 2005.

This Airworthiness Directive becomes effective on 16 June 2005.

Background: Transport Canada has advised that inadequate electrical grounding of the fuel boost pump and the fuel drain solenoid valve, combined with fuel hoses contact, could cause arcing in the main fuel cell which may in turn cause an explosion and resultant fire.

This Directive requires a one time inspection to ensure correct grounding and, if necessary the disconnecting and stowage of the engine fuel purge hose.

FMI: http://casa.gov.au/airworth/airwd/NEW/urgent.htm