NONE · BOEING 747 · 2015-10-02 · Russian airspace, JA
Event
NTSB number
ENG16IA001
Event ID
20151005X35533
Type
Incident
Date
2015-10-02
Location
Russian airspace, JA
Coordinates
55.216388, 160.109725
Injuries
Highest injury
NONE
Fatal
0
Serious
0
Minor
0
Uninjured
367
Total aboard
367
Aircraft
Make
BOEING
Model
747
Registration
N662US
FAR Part
121
Engines
4
Damage
MINR
Conditions
Light
NR
Weather
Unk
Probable cause
The PW4056 engine experienced an in-flight loss of power because of damage to the low-pressure turbine (LPT) because of the inadequate overhaul inspection and repair instructions that existed at the time of the LPT module's last overhaul. A vane hook in the LPT case wore to the point to allow a 3rd stage turbine vane cluster to disengage and eventually fall into the path of the 3rd stage turbine blades causing extensive downstream damage to the LPT module.