Service difficulty report · Engine · Boeing 777222

Difficulty date
September 6, 2000
Submitted
November 21, 2000
Operation
Air carrier
Aircraft
N777UA
Make and model
Boeing 777222
Aircraft serial
26916
Aircraft time
22,486 hours, 4,600 cycles
Engine
Pwa PW4077
Engine time
11,661 hours, 1,886 cycles
Part
Engine
Condition
Malfunctioned
Location
Right
Part time
416 hours, 88 cycles
Component
Engine · Pwa · PW4077D
Stage of operation
CR
How discovered
O
Nature of condition
R, J
Precautionary procedure
O

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

PER CREW, RT ENG NOT PRODUCING COMMANDED THRUST. EPR N1 CAUTION. MOMENTARY RPM LOSS. *S/D* DURING DESCENT THRU 19,000 FT, THROTTLES WERE ADVANCED, RT ENG ACCELERATED SLOWER THAN THE LEFT TAKING SLIGHTLY MORE THAN 15 SEC TO RESPOND, EICAS ANNUNCIATED ENG THRUST RT ENG ACCELERATIONS WERE NORM FOR THE REMAINDER OF THE FLT AND THE ENG PASSED AN ACCEL-DECEL GROUND RUNUP TEST AFTER LANDING. THIS TYPE OF DELAYED ACCELERATION AT ALTITUDES ABOVE 16,000 FT HAS BEEN ATTRIBUTED TO BODIE RESET AND OVERSHOOT PREVENTION LOGIC IN THE ELECTRONIC ENG CONTROL (EEC), WHICH WAS SOFTWARE VERSION SCN-8C. EEC SOFTWARE SCN-9, WHICH INCLUDES BODIE LOGIC IMPROVEMENTS, WAS SUBSEQUENTLY RETROFITTED ON THIS ENG.