Airworthiness Directive · Amendment 39-16760 · Ice and rain protection
The Boeing Company Model 747 Airplanes and Model 767 Airplanes Equipped With General Electric Model CF6-80C2 or CF6-80A Series Engines
This AD applies to The Boeing Company Model 747 airplanes and Model 767 airplanes, certified in any category, equipped with General Electric Model CF6-80C2 or CF6-80A series engines.
We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires revising the airplane flight manual (AFM) to advise the flightcrew to use certain procedures during descent in certain icing conditions. This AD was prompted by reports of several in-flight engine flameouts, including multiple dual engine flameout events and one total power loss event, in ice-crystal icing conditions. We are issuing this AD to ensure that the flightcrew has the proper procedures to follow in certain icing conditions. These certain icing conditions could cause a multiple engine flameout during flight with the potential inability to restart the engines, and consequent forced landing of the airplane.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Within 14 days after the effective date of this AD, revise the Limitations Section of the Boeing 747 or 767 AFM, as applicable, to include the following statement. This may be done by inserting a copy of this AD into the AFM.
“Prior to reducing thrust for descent in visible moisture and TAT less than 10 °C, including SAT less than −40 °C, nacelle anti-ice switch must be in the ON position. At or below 22,000 ft, wing anti-ice selector must be in the ON position. When these icing conditions (visible moisture and TAT less than 10 °C, including SAT less than −40 °C) are no longer present or anticipated, place the nacelle and wing anti-ice selectors in the OFF (or AUTO) position.”
Note 1: When a statement identical to that in paragraph (g) of this AD has been included in the general revisions of the AFM, the general revisions may be inserted into the AFM, and the copy of this AD may be removed from the AFM.
