Compressor surging of Boeing 737-800 left engine

CFM-56 7B engine

20th August, 2009

Launceston to Sydney, Australia

www.lh5.ggpht.com Accessed Nov.4 , 2010

Fuel Flow (FF) decreased

Exhaust Gas Temperature (EGT) increased

35 minutes after takeoff

High Pressure Compressor (HPC) surge

Engine set to flight idle

Aircraft returned safely

B 737-800 Power Plant Training Manual, ALTEON

B 737-800 Power Plant Training Manual, ALTEON

Investigated by Australian Transport Safety Board (ATSB)

Borescope inspection conducted

Flight Data Recorder (FDR) and cockpit voice recorder sent to ATSB

36 similar incidents have occurred

Engine sent to GE facility◦ Full engine teardown and inspection

Borescope inspection on the left engine◦ Damage to HPC rotors

◦ Missing HPC seal segments around 3rd stage stator

◦ Loose HPC seals observed on 1st and 2nd stage

FDR data analysis◦ FF & EGT changed over the last two flights

Engine teardown◦ Seal segments

ATSB, Aviation Occurrence Investigation A0-2009-053, Final Report, July 2010

ATSB, Aviation Occurrence Investigation A0-2009-053, Final Report, July 2010

Some airline operators have changed check intervals

Manufacturer has redesigned parts

1. The check times should be reduced

2. Investigation of improved assembly, material, better fitting

3. Up-to-date Engine Health Monitoring (EHM)

Material

selection

Assembly

procedureMaintenance

Industry

practices

Failure rate influenced by◦ Maintenance check intervals

◦ Materials selection

◦ Assembly procedures

Constant monitoring can reveal problems

Questions?