Airworthiness Directive · Amendment 39-15335 · Boeing Model 777-200 and -300 Series Airplanes Equipped With Rolls-Royce RB211-TRENT 800 Series Engines
Boeing Model 777-200 and -300 Series Airplanes Equipped With Rolls-Royce RB211-TRENT 800 Series Engines
This AD applies to Boeing Model 777-200 and -300 series airplanes, certificated in any category, equipped with Rolls-Royce RB211 TRENT 800 engines.
The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 777-200 and -300 series airplanes. This AD requires revising the airplane flight manual to provide the flightcrew with new ground procedures for shedding core ice during long taxi periods in freezing fog with visibility of 300 meters or less. For airplanes unable to perform the shedding procedure after prolonged taxiing in freezing fog with visibility of 300 meters or less, this AD requires certain investigative and corrective actions. This AD results from reports of engine surges and internal engine damage due to ice accumulation during extended idle thrust operation in ground fog icing conditions. We are issuing this AD to prevent internal engine damage due to ice accumulation and shedding, which could cause a shutdown of both engines, and result in a 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 777 Airplane Flight Manual (AFM) to include the following statements. This may be done by inserting a copy of this AD in the AFM.
When freezing fog with visibility of 300 meters or less is reported and
(a) The OAT is 0 degrees C to −6 degrees C then run up the engines to 50% N1 for 1 minute every 45 minutes taxi time, or
(b) The OAT is −7 degrees C to −13 degrees C then run up the engines to 59% N1 for 1 minute for every 45 minutes taxi time, or
(c) The OAT is colder than −13 degrees C and taxi time exceeds 45 minutes, there is no run-up procedure; the engines must be manually de-iced.
Regardless of temperature, if the core ice shedding procedure described above is not accomplished within 45 minutes total taxi time in freezing fog with visibility of 300 meters or less, but takeoff can be achieved within 60 minutes total taxi time in freezing fog with visibility of 300 meters or less, takeoff is permitted. A borescope inspection is required within 10 flights. Takeoff is not permitted if total taxi time in freezing fog with visibility of 300 meters or less exceeds 60 minutes without accomplishing the above core ice shed procedure. The engine core must be manually de-iced.”
(g) When a statement identical to that in paragraph (f) 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.
If takeoff is not accomplished in freezing fog, with visibility of 300 meters or less, within 60 minutes total taxi time, before further flight, perform an inspection for ice of the variable inlet guide vanes (VIGVs), inspect the low pressure compressor (fan) for ice, and ensure that all fan, spinner, air intake splitter fairing, and VIGV surfaces are free of ice after engine operation in freezing fog with visibility of 300 meters or less, in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO). One acceptable method of compliance is Chapter 12-33-03 of the Boeing 777 Airplane Maintenance Manual (AMM).
(1) If no ice is detected, the time already completed in freezing conditions can be reset to zero for subsequent operation.
(2) If any ice is detected, before further flight, manually de-ice the engine core inlet. Upon completion of the manual de-ice process, the fan, spinner, air intake splitter fairing, and VIGV surfaces must be free of ice and all residual water removed. Two acceptable methods to manually de-ice the engine can be found in Chapter 12-33-03 of the Boeing 777 AMM. At no time during the manual de-ice process should the temperature of the air supplied exceed 176 degrees Fahrenheit.
(i) For airplanes on which the core ice shedding procedure is not accomplished within 45 minutes total taxi time, but that achieve takeoff within 60 minutes total taxi time in freezing fog with visibility of 300 meters or less, regardless of temperature during ground operations in freezing fog with visibility of 300 meters or less: Within 10 flight cycles after takeoff, perform a borescope inspection to detect missing material of the intermediate pressure compressor (IPC) stage 1 blades. If any material is found to be missing, do a full borescope inspection of the IPC and high pressure compressor (HPC) before further flight. Do the actions in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. One acceptable method of compliance is to perform all applicable borescope inspections in accordance with Chapter 72-00-00 of the Boeing 777 AMM. If any damage is detected, further action in accordance with the current AMM limits must be taken before further flight.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
