GE Aviation

This AD as written, inaccurately represents the incident in that fact that there was a very specific set of circumstances in the course of operation that were unique to this event which establishes it as a very rare occurrence. This unique set of circumstances supports the FAA determination that this is an AD for a piece part exposure (Category 5 Service Bulletin) verses driving an action that a Category 1 or 2 Service Bulletin would accomplish. GE recognizes the FAA’s position to mitigate a future event but the actions to AD a Category 5 Service Bulletin supports the assessment that this is a very rare occurrence and the actions that are needed to be taken are not urgent to correct an unsafe condition. GE finds it necessary to change to the specific words listed below in order to accurately represent the set of circumstances and mitigation plan: ·In the SUMMARY and Unsafe Condition sections the sentence: ‘Both engines experienced high-altitude flameouts.’ This event was the result of a high altitude and high power event and the following wording would be a more accurate representation: ‘As a result of a high altitude aircraft stall and upset, both engines experienced high-power flameouts.’ ·In the SUMMARY and the Unsafe Condition sections the sentence: ‘We are proposing this AD to prevent the inability to restart both engines after flameout due to excessive friction of the 4-step seal, which could result in subsequent forced landing of the airplane.’ The following wording would more be a more accurate representation and support the assessment that this is a very rare occurrence and the recommended actions are not prevalent as proven by the category level of this service bulletin: ‘We are proposing this AD to enhance the ability to restart an engine after flameout by reducing the friction in the 4-step seal. The inability to restart an engine following a dual engine flameout may subsequently result in a forced landing of the airplane.’ ·In the Discussion section the sentence: ‘This will ultimately reduce the possibility of the HP rotor locking after a high altitude flameout when HP rotor rotation is not maintained during descent.’ This event was the result of a high altitude and high power event and the following wording would be a more accurate representation: ‘This will ultimately reduce the possibility of the HP rotor locking after a high-altitude, high-power, flameout when HP rotor rotation is not maintained during descent.’