83-07-12 R1 PILATUS BRITTEN-NORMAN LTD.: Amendment 39-4615. Applies to BN-2, BN2A, and BN-2B Islander Series equipped with wing tip fuel tanks and BN-2A MK. III Trislander Series (all Serial Numbers) airplanes certificated in any category.
Compliance: Required as indicated, unless already accomplished.
To detect erosion of the wing tip tank fuel transmitter floats, which could restrict fuel flow and result in the loss of power, accomplish the following:
a) Within the next 100 hours time-in-service after the effective date of this Airworthiness Directive (AD) and thereafter at intervals not to exceed 100 hours time-in-service:
1) Remove and visually inspect the wing tip tank fuel transmitter floats for evidence of cracking, fretting, or erosion in accordance with the instructions provided in the "Inspection and Rectification" section of Pilatus Britten-Norman Service Bulletin (SB) No. BN- 2/SB.154, Issue 1, dated February 12, 1982, (hereinafter referred to as the SB) or an FAA approved equivalent.
2) If any fuel transmitter float is found with cracks, fretting, or erosion during the accomplishment of the visual inspection in accordance with paragraph a)1) of this AD, prior to further flight, replace the float with a serviceable unit of the same part number and continue the repetitive visual inspections in accordance with paragraph a)1) of this AD.
3) If any fuel transmitter float is found with excessive erosion during accomplishment of the visual inspection in accordance with paragraph a)1) of this AD, prior to further flight, drain the affected tank and clean the filters, including also the fuel supply system, through the auxiliary pumps, to the engine together with all fuel filters enroute.
4) Reinstall wing tip tank fuel transmitters in accordance with instructions provided in the "Inspection and Rectification" section of the SB.
b) The intervals between repetitive inspections required by this AD may be adjustedup to 10 percent of the specified inspection intervals to allow them to be accomplished concurrent with other scheduled maintenance on these airplanes.
c) Aircraft may be flown in accordance with FAR 21.197 to a location where this Airworthiness Directive (AD) can be accomplished.
d) An equivalent method of compliance with this AD, if used, must be approved by the Manager, Aircraft Certification Staff, AEU-100, Europe, Africa and Middle East Office, FAA, c/o American Embassy, 1000 Brussels, Belgium.
This amendment becomes effective on April 11, 1983.