LN-SEK
ScanFlyer Gold
Trøbbel med GE90 motoren?
Ser ut som det er problemer med FADEC (motorstyring).
Quote fra A-net:
We have received a report of two occurrences of engine thrust rollback (reduction) during takeoff on Boeing Model 777-300ER series airplanes powered by GE Model GE90-115B engines. In both cases, only one engine was affected. The N1 (fan speed - the normal thrust setting parameter for this engine type) thrust level on the affected engine progressively dropped resulting in a thrust loss of 65 to 77 % due to an erroneous N1 command computed by the Full Authority Digital Engine Control (FADEC). In both cases, the engine recovered to the proper N1 thrust level as the airplane climbed beyond 400 feet above ground level. In one case, the operator elected to return to the departure airport after reaching cruise. In the other case, the operator continued to its destination. There were no further anomalies reported during the remainder of the flights. No flight deck messages or maintenance indications occurred as a result of the event.
Investigation indicates that these events are the results of a software algorithm in the FADEC that was introduced in software version A.0.4.5 (GE90-100 Service Bulletin 73-0021). Investigation also indicates that a dual-engine thrust rollback could occur just after V1 (takeoff decision speed after which takeoff is to proceed even after an engine failure), which would result in the airplane not having adequate thrust to safely complete the take off.
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Hele diskusjonen på A_net
Ser ut som det er problemer med FADEC (motorstyring).
Quote fra A-net:
We have received a report of two occurrences of engine thrust rollback (reduction) during takeoff on Boeing Model 777-300ER series airplanes powered by GE Model GE90-115B engines. In both cases, only one engine was affected. The N1 (fan speed - the normal thrust setting parameter for this engine type) thrust level on the affected engine progressively dropped resulting in a thrust loss of 65 to 77 % due to an erroneous N1 command computed by the Full Authority Digital Engine Control (FADEC). In both cases, the engine recovered to the proper N1 thrust level as the airplane climbed beyond 400 feet above ground level. In one case, the operator elected to return to the departure airport after reaching cruise. In the other case, the operator continued to its destination. There were no further anomalies reported during the remainder of the flights. No flight deck messages or maintenance indications occurred as a result of the event.
Investigation indicates that these events are the results of a software algorithm in the FADEC that was introduced in software version A.0.4.5 (GE90-100 Service Bulletin 73-0021). Investigation also indicates that a dual-engine thrust rollback could occur just after V1 (takeoff decision speed after which takeoff is to proceed even after an engine failure), which would result in the airplane not having adequate thrust to safely complete the take off.
Kanskje Dag har mer info ?
Hele diskusjonen på A_net
