Airworthiness Directive · Amendment 39-12048 · Eurocopter Deutschland GMBH Model BO-105CB-5 and BO-105CBS-5 Helicopters
Eurocopter Deutschland GMBH Model BO-105CB-5 and BO-105CBS-5 Helicopters
Model BO-105 CB-5, and BO-105CBS-5 helicopters, certificated in any category.
Note 1: This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For helicopters that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
This amendment supersedes an existing airworthiness directive (AD) that applies to Eurocopter Deutschland GMBH (ECD) Model BO-105CB-5 and BO-105CBS-5 helicopters. That AD currently requires, before further flight, creating a component log card or equivalent record and determining the calendar age and number of flights on each tension- torsion (TT) strap. This amendment requires before further flight, establishing a life limit for certain main rotor TT straps. This amendment is prompted by a need to establish a life limit for certain TT straps because of an accident in which a main rotor blade (blade) separated from an ECD Model MBB-BK 117 helicopter due to fatigue failure of a TT strap. The same part-numbered TT strap is used on the ECD Model BO-105 helicopters. The actions specified by this AD are intended to prevent fatigue failure of a TT strap, loss of a blade, and subsequent loss of control of the helicopter.
To prevent fatigue failure of a tension-torsion (TT) strap, loss of a main rotor blade (blade), and subsequent loss of control of the helicopter, accomplish the following:
(a) Before further flight:
(1) Remove TT straps, part number (P/N) 2604067 (Bendix) or J17322-1 (Lord), from service or re-identify them as P/N 117-14110 or 117-14111, respectively, in accordance with the Accomplishment Instructions, paragraph 2.B.1.2., Eurocopter Deutschland GMBH Alert Service Bulletin BO 105 No. ASB-BO 105-10-113, Revision 2, dated November 16, 1999 (ASB). TT straps, P/N 2604067 (Bendix) or J17322-1 (Lord), are no longer eligible for installation.
(2) Create a component log card or equivalent record for each TT strap.
(3) Review the history of the helicopter and each TT strap. Determine the age since initial installation on any helicopter (age) and the number of flights on each TT strap. Enter both the age and the number of flights for each TT strap on the component log card or equivalent record. When the number of flights is unknown, multiply the number of hours time-in-service (TIS) by 5 to determine the number of flights.
(4) Remove any TT strap from service if the total hours TIS or number of flights and age cannot be determined.
(b) Before further flight, remove any TT strap, P/N 117-14110 or 117-14111, that has been in service 120 months since initial installation on any helicopter or accumulated 25,000 flights (a flight is a takeoff and a landing). Replace the TT strap with an airworthy TT strap.
(c) This AD revises the Airworthiness Limitations Section of the maintenance manual by establishing a life limit for the TT strap, P/N 117-14110 and 117-14111, of 120 months or 25,000 flights, whichever occurs first.
