Boeing Bulletins

PW-2 PW4000 Engine Operation In Heavy Rain Or Hail

14 February 2007

Effectivity

Please refer to source document.

Reason

This bulletin provides information informing flight crews of temporary recommended procedures for maintaining a minimum thrust setting of approach idle if heavy rain or hail is encountered or anticipated.

Information in this bulletin is recommended by The Boeing Company, but may not be FAA approved at the time of writing. In the event of conflict with the FAA approved Airplane Flight Manual (AFM), the AFM shall supersede. The Boeing Company regards the information or procedures described herein as having a direct or indirect bearing on the safe operation of this model airplane.

Background Information

In compliance with Airworthiness Directive 90-20-11, PW4000 series engines are currently limited inflight to a minimum thrust setting of approach idle. A new Airworthiness Directive 93-08-16 has been released which will restore inflight low idle operation. Boeing Service Bulletin 767-73-0041 is expected to be released in late November, 1993 providing the necessary information for this modification.

However, the Boeing preferred method of operating the PW4000 series engine in very heavy rain or hail is to maintain a minimum thrust setting of approach idle. An airplane modification is planned to automatically set a minimum thrust setting of approach idle when ignition is selected to CONT. In the interim, Boeing recommends that the flight crew procedures be modified to maintain a minimum of approach idle in conditions likely to result in very heavy rain or hail encounter. Increasing engine RPM to approach idle will assure satisfactory engine operation.

Operating Instructions

Flights should be conducted to avoid thunderstorm activity by over flight or circumnavigation. To the maximum extent possible, heavy rain or hail should also be avoided. Weather radar, pilot reports, and flight crew observations may be used by the flight crew to determine when heavy rain or hail is anticipated. Should flight in heavy rain or hail be encountered or anticipated, accomplish the following procedure:

Administrative Information (Extract)

This Operations Manual Bulletin will be canceled after Boeing is notified that all affected airplanes in the operators fleet have been modified by Boeing Service Bulletin 767-73-0044.