Airworthiness Directive · Amendment 39-18276 · Main gear box
Airbus Helicopters Deutschland GmbH (formerly Eurocopter Deutschland GmbH) (Airbus Helicopters) Helicopters
This AD applies to Model BO-105A, BO-105C, and BO-105S helicopters with a Mann oil filter part number (P/N) 6140063321 or a Purolator oil filter P/N 1740001-13, installed, certificated in any category.
We are adopting a new airworthiness directive (AD) for Airbus Helicopters Model BO-105A, BO-105C, and BO-105S helicopters. This AD requires inspections to detect oil contamination in the main gearbox (MGB). This AD was prompted by initial findings from an accident investigation of a Model BO-105 helicopter, which indicated deterioration of the MGB caused by a contaminated oil supply. The actions of this AD are intended to detect oil contamination in the MGB, which could result in MGB deterioration, MGB failure, and subsequent loss of control of the helicopter.
You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.
(1) Within 100 hours time-in-service (TIS) or at the next MGB magnetic plug or chip detector inspection, whichever occurs first, and thereafter at intervals not to exceed 100 hours TIS if a Mann oil filter is installed or 600 hours TIS if a Purolator oil filter is installed, clean and inspect the MGB oil filter for chips and the MGB magnetic plug for fine particles (metallic fuzz) or chips. A “chip” is a solid piece of metal but not metallic fuzz.
(i) If there are no chips on the MGB oil filter or on the magnetic plug, and the metallic fuzz covers less than 25% of the magnetic plug, clean the magnetic plug.
(ii) If there are no chips on the MBG oil filter or on the magnetic plug, but the metallic fuzz covers 25% or more of the magnetic plug, flush the main transmission, change the oil, perform a ground run for 15 minutes at the flight-idle power setting, and then re-inspect the MGB oil filter and magnetic plug for a chip and the quantity of metallic fuzz on the metallic plug.
(iii) If there is a chip on the MGB oil filter or on the magnetic plug, or, after complying with paragraph (e)(1)(ii) of this AD, metallic fuzz covers 25% or more of the magnetic plug, replace the main transmission with an airworthy main transmission and clean the oil cooler and oil lines.
(2) At intervals not to exceed 10 hours TIS if a Mann oil filter is installed and 50 hours TIS if a Purolator oil filter, inspect the magnetic plug for a chip or metallic fuzz in accordance with the requirements of paragraph (e)(1) of this AD.
(3) If a Purolator oil filter has been installed on a helicopter, do not install a Mann oil filter on that helicopter.
