Aviation Herald update - new report points to fuel contamination in Surabaya.
Accident: Cathay A333 at Hong Kong on Apr 13th 2010, engine stuck at high thrust
By Simon Hradecky, created Wednesday, Aug 11th 2010 10:16Z, last updated Wednesday, Aug 11th 2010 10:16Z
"In a new preliminary report Hong Kong's Civil Aviation Department (CAD) said, that the engine fuel components, relevant fuel samples and monitor filters in the vessel of the dispenser refueling the aircraft in Surabaya were collected and sent to the UK for analysis. Flight data and cockpit voice recorders were read out.
An examination of the engine fuel components showed, that the main metering valves (MMV) of the fuel metering units (FMU) were seized, the left at a position consistent with the 70% N1 of the left hand engine, the right hand at a position consistent with the 17% N1 achieved by the right hand engine. The right hand engine's variable stator vane controller (VSVC) was also found seized.
Fine spherical particles (spheres) were found in the FMU, VSVC and variable stator vane actuator (VSVA) of both engines. No fault has been observed to any component other than those associated with the contamination by spheres. The spheres could not be generated from within the airframe or engine systems under normal operating conditions and environment.
The fuel samples also showed contaminations with such spheres.
The monitor fuel filters from the dispenser also showed traces of such spheres, spheres were also found in fuel samples taken downstream of the monitor filters. The spheres appeared similiar to those found on the aircraft.
The exact nature of the spheres is still under investigation.
The flight data recorders and quick access recorders as well as aircraft monitoring system showed no abnormal commands sent from the electronic engine control or autothrust system. The abnormal engine condition therefore is believed to be the result of the contamination with spheres leading to the seizure of the MMVs.
The aircraft had loaded 24400 kg of fuel from Surabaya's hydrant refuelling at stand 8, which was part of a circuit refuelling stands 1 to 10. Prior to the event there had been extensive work on that circuit as part of the Surabaya Airport extension project. The refueling circuit was isolated for the investigation.
Inspection of the refuelling circuit revealed, that some of the re-commissioning procedures were not in line with guidelines and practises commonly used in the aviation industry. The re-commissioning had not been completed when B-HLL and other aircraft were already being refueled from that circuit."
Quote: Without drawing a conclusion out of turn from the HK CAD investigators, the Indonesian Ministry of Transport is currently conducting a parallel investigation into the fuel quality, storage, and delivery at SUB.
If one were to think logically about the situation, not many variables are shared between the engines that changed sometime after landing in SUB.
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