AD 2021-10-08 Requires Removing Certain Switch Units From Service

The FAA is adopting a new airworthiness directive (AD) for certain Bell Textron Canada Limited (type certificate previously held by Bell Helicopter Textron Canada Limited) Model 206L series helicopters.

This AD was prompted by a manufacturing flaw that could cause low fuel level detector switch units (switch units) to hang in the high position and fail to indicate a low fuel condition. This AD requires removing certain switch units from service and prohibits installing those switch units. This AD also requires accomplishing an operational test of certain other switch units, and depending on the results, removing the switch unit from service. This AD also prohibits installing those certain other switch units unless they pass an operational test. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective June 11, 2021.

Supplementary Information: The FAA issued a supplemental notice of proposed rulemaking (SNPRM) to amend 14 CFR part 39 by adding an AD that would apply to Bell Textron Canada Limited (type certificate previously held by Bell Helicopter Textron Canada Limited) Model 206L, 206L-1, 206L-3, and 206L-4 helicopters, with certain switch units part number (P/N) 206-063-613-003 installed. The SNPRM published in the Federal Register on March 12, 2021 (86 FR 14020). The FAA preceded the SNPRM with a notice of proposed rulemaking (NPRM) that published in the Federal Register on June 22, 2006 (71 FR 35836).

The NPRM was prompted by Canadian AD CF-2004-24, dated November 24, 2004, issued by Transport Canada, which is the aviation authority for Canada, to correct an unsafe condition for Model 206L series helicopters. Transport Canada advised that eight low fuel level detectors of listed serial numbers (S/Ns) may have been installed on Model 206L series helicopters. These detectors could hang in the high position and fail to indicate the low fuel condition. Accordingly, Transport Canada advised removing the affected switch units from service.

The SNPRM was prompted by a significant lapse of time since publication of the NPRM. The SNPRM also revised the NPRM by updating the type certificate holder's name, updating the estimated cost information, clarifying and expanding the applicability, clarifying the requirements, adding a compliance time, adding parts installation prohibitions, and updating the AD format.

The SNPRM proposed to require removing switch unit P/N 206-063-613-003 with S/N 1413, 1414, 1415, 1424, 1428, 1430, 1432, and 1433 from service and prohibit installing those switch units.

The SNPRM proposed to require accomplishing an operational test of switch unit P/N 206-063-613-003 with a missing or illegible switch unit S/N or with an S/N that cannot be determined, and if the operational test fails, removing the switch unit from service. The SNPRM also proposed to prohibit installing switch unit P/N 206-063-613-003 with a missing or illegible switch unit S/N or with an S/N that cannot be determined unless it passes an operational test.

FMI: www.regulations.gov