Emergency landing Cathay A330-300

[Willit Run]

Electronic Engine controls are good for the most part, but what happens if one of the base parameters becomes disconnected from the EEC computer?? The EEC will do what it wants, including go to a subidle state, (if thats what it thinks it should do) and there is nothing a pilot can do about it. How do I know? it happened to me! (on a boeing).

[Bleve]

The EEC will do what it wants, including go to a subidle state, (if thats what it thinks it should do) and there is nothing a pilot can do about it.

Ummm, on my Boeing we can turn the EEC off and get direct thrust lever control of the engine.

[Helicopter doctor]

Fuel Contamination?

Received this this morning from a former airline pilot friend of mine.....

Pertamina’s Avtur Fuel Remains under Investigation
An investigation team formed by the Ministry of Transportation continues to investigate a case related to poor quality of aviation turbine (avtur) fuels sold by PT Pertamina, which caused a damage to airbus A330 owned by Cathay Pacific Airways that landed in Hong Kong Airport on April 13, 2010. The team is analyzing the quality of avtur fuel owned by PT Pertamina in the Juanda Airport, Surabaya. One of the objects subject to investigation is avtur fuel storage in the airport. Director of Certification of Aviation Worthiness Yuris Hasibuan said that Pertamina, National Committee for Transportation Safety (KNKT) and the Directorate General of Air Transportation has investigated the avtur fuel, with avtur fuel sent to a laboratory for further analysis.(Kontan Daily, 3/5)

[Freehills]

CAD preliminary report now out

http://www.cad.gov.hk/reports/AB-01-2010e.pdf

[Helicopter doctor]

Emergency Landing

From yesterday's Aviation Herald.

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 10:16ZIn 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.

Doc

[pax2908]

But how many a/c would have been refueled there, around that time, and also until the circuit was isolated / taken out of service?

[TyroPicard]

Perhaps they were unlucky and collected all the spheres in one go - presumably further contamination of the circuit did not occur.

[Dani]

So, what are spheres exactly? Are they made of metal or of stones or other materials? Are these commonly knows as chips? What is the possible source of this? I have never heard of this and cannot imagine what happened exactly.

Thanks for any hint,
Dani

[llagonne66]

CAD preliminary report now out

So much for all those A330 bashers ....

[mm43]

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.

My initial reaction is that the contaminating spheres are actually weld splatter. In other words the line had not been flushed correctly following repairs, and neither was a filter test done.

mm43

[Helicopter doctor]

Emergency Landing

This poor commissioning of the fuel system is a fairly typical occurrence based in a lack of awareness of standards or a disregarding of standards. Pertamina are generally very good at following routine procedures, however I imagine work like this would be in the hands of a contractor with little knowledge of what was required to ensure serviceability before the system was put back into service after completion of work.

An example is the airport of Sepinggan, East Kalimantan, where an underground fuel system was installed during airport reconstruction about 15 years ago. The piping used was galvanized, which is a no-no. The system was condemned and never used, however the aprons were completed so the system would have to be cut out of the concrete to repair it. This was not done and tankers are used to this day. mm43, I imagine weld splatter would be too big to pass a typical 10 micron filter and I think all underwing fuel units have filters. Maybe someone can confirm this?

A few years ago there was a OEM Service Bulletin concerning use of alcohol for cleaning hydraulic actuator parts. Quote:

Tests have shown that acrylic polymer additives, normally present
in hydraulic fluid, will precipitate out of the solution when
alcohol and hydraulic fluid are combined together. The acrylic
polymer will tend to adhere to areas of parts in very close contact
with each other and where very little or no hydraulic fluid flow is
present. The acrylic polymer has a sticky characteristic and will
also tend to attract and hold any particulate contaminant present
in the system fluid. If the acrylic polymer is present between
close fitting surfaces such as the end lands of spool and sleeve
assemblies in flight control cylinders, a sticking condition may be
created which can interfere with free movement of the spool.
Increasingly cold temperatures increase the polymer's viscosity and
as a consequence, pilot input forces required to move the spool are
raised and the attendant response of the flight controls can be
affected.

Maybe some chemical left in the system as part of the repair work mixed with the Jet A-1 to produce something similar?

Doc

[FlexibleResponse]

I missed the link to the CAD Accident Bulletin 3/2010 in "Helicopter Doctor's" post above.

The CAD report is very explicit in that fuel contamination caused the Main Metering Valves of both engines to seize (the No 1 engine jammed at 70% N1 and the No 2 engine jammed at 17% N1).

Helicopter Doctor's link:
http://www.cad.gov.hk/reports/AB-03-2010e.pdf

[Carjockey]

Fuel Contamination?

Airport fuelling systems generally have the fuel filtering system and the fuel sampling points installed after the fuel storage tanks and before the fuel hydrant system.

That being the case, fuel entering the hydrant system is considered ‘pure’ and safe for use.

If a section of a fuel hydrant system requires repair or re-work, the contractor carrying out the work, and the relevant airport authority, would need to be very sure that the re-worked section was thoroughly cleaned and free of contaminants before the section is re-commissioned.

If realistic construction procedures are not applied and strictly followed before re-commissioning, the potential for contaminated fuel being supplied to aircraft is very real.

Some examples of piping contamination which I have personally witnessed are:
1. Welding rod stubs.
2. Welders gloves/gauntlets and eye glass (UV) filters.
3. Used grinding discs.
4. Cigarette packets, cigarette stubs, lighters and boxes of matches.
5. Sandwich wrappers, polystyrene food containers and food remnants.
6. Plastic water bottles, both empty and partially full.
7. And etc, etc.

Bearing in mind the location of refuelling in this particular case, I don’t find it too difficult to believe that some kind of fuel contamination may have occurred.

CJ