The risk of a fuel fed engine fire
Thread Starter
The risk of a fuel fed engine fire
On 27 June 2016, a Boeing 777-300ER powered by GE90-115B engines returned to Singapore when what was initially identified as a suspected right engine oil quantity indication problem evidenced other abnormal symptoms relating to the same engine. The engine caught fire on landing. The substantial fire was quickly contained and an emergency evacuation was not performed. The cause of the low oil quantity indication and the fire was a failure of the right engine Main Fuel Oil Heat Exchanger which had resulted in lubrication of the whole of the affected engine by a mix of jet fuel and oil.
See report below.
https://www.skybrary.aero/index.php/...b884-276530305
In the late 1950's, a USAF flight safety magazine called THE MAC FLYER available at most RAAF flying units, published an article on the danger of engine fuel leaks in flight. The gist of the article was if a fuel leak in a piston engine was suspected, with the symptoms being fluctuating fuel pressure with the engine running normally, a fire may erupt if slipstream through the engine cowls was disturbed by changing power settings.
The following highlighted text from the Boeing 777 incident report reveals this is possible in principle even with a jet engine.
"but the absence of fire whilst the aircraft was airborne could be attributed to "the high velocity of the airflow over the exterior of the engine which prevented both the ignition and sustained combustion"
This contributor was approaching the circuit at Townsville in a RAAF Dakota when the starboard engine fuel pressure gauge needle began to fluctuate. The engine was running normally. It was decided not to change the power setting in case the problem was associated with a fuel leak. Even feathering the propeller would change the airflow characteristics through the engine since closing the throttle was the first action leading up to feathering the prop.
The decision was made to maintain the same airspeed and cruise power setting until on final approach and then cut the mixture lever to idle cut-off thus cutting the fuel to the engine..
After landing the aircraft was stopped on the runway and towed to the tarmac. Investigation revealed a loose fuel line connection to the engine and evidence of fuel spray. Of course we were not to know if a change in power setting would also cause a change airflow through the engine cowls that could ignite the fuel leak. In fact we didn't suspect a fuel leak in the engine . However, the MAC FLYER article rang a bell and it was decided that if the cause of the fluctuating fuel pressure gauge was indeed a fuel leak, it would make sense to cut the mixture control in the cruise rather than go through the feathering procedure.
By cutting the mixture control and thus hopefully stopping the fuel spray it was felt the chances of fuel ignition caused by with airflow change through the engine cowls was lessened.
We would not have been aware of the danger of fuel ignition with a change of airflow with a suspected fuel leak unless we had previously read the MAC FLYER article on the subject. The incident proved there is great value in reading old incident/accident reports.
For that reason, pilots young and old or new to Pprune would be wise to find the time to browse through the old Department of Civil Aviation Aviation Safety Digests available at: Aviation Safety Digests now available Digital
See report below.
https://www.skybrary.aero/index.php/...b884-276530305
In the late 1950's, a USAF flight safety magazine called THE MAC FLYER available at most RAAF flying units, published an article on the danger of engine fuel leaks in flight. The gist of the article was if a fuel leak in a piston engine was suspected, with the symptoms being fluctuating fuel pressure with the engine running normally, a fire may erupt if slipstream through the engine cowls was disturbed by changing power settings.
The following highlighted text from the Boeing 777 incident report reveals this is possible in principle even with a jet engine.
"but the absence of fire whilst the aircraft was airborne could be attributed to "the high velocity of the airflow over the exterior of the engine which prevented both the ignition and sustained combustion"
This contributor was approaching the circuit at Townsville in a RAAF Dakota when the starboard engine fuel pressure gauge needle began to fluctuate. The engine was running normally. It was decided not to change the power setting in case the problem was associated with a fuel leak. Even feathering the propeller would change the airflow characteristics through the engine since closing the throttle was the first action leading up to feathering the prop.
The decision was made to maintain the same airspeed and cruise power setting until on final approach and then cut the mixture lever to idle cut-off thus cutting the fuel to the engine..
After landing the aircraft was stopped on the runway and towed to the tarmac. Investigation revealed a loose fuel line connection to the engine and evidence of fuel spray. Of course we were not to know if a change in power setting would also cause a change airflow through the engine cowls that could ignite the fuel leak. In fact we didn't suspect a fuel leak in the engine . However, the MAC FLYER article rang a bell and it was decided that if the cause of the fluctuating fuel pressure gauge was indeed a fuel leak, it would make sense to cut the mixture control in the cruise rather than go through the feathering procedure.
By cutting the mixture control and thus hopefully stopping the fuel spray it was felt the chances of fuel ignition caused by with airflow change through the engine cowls was lessened.
We would not have been aware of the danger of fuel ignition with a change of airflow with a suspected fuel leak unless we had previously read the MAC FLYER article on the subject. The incident proved there is great value in reading old incident/accident reports.
For that reason, pilots young and old or new to Pprune would be wise to find the time to browse through the old Department of Civil Aviation Aviation Safety Digests available at: Aviation Safety Digests now available Digital
Last edited by Centaurus; 10th Jan 2018 at 07:04.
The incident proved there is great value in reading old incident/accident reports.
For that reason, pilots young and old or new to PPRuNe would be wise to find the time to browse through the old Department of Civil Aviation Aviation Safety Digests available at: https://www.pprune.org/pacific-gener...e-digital.html
For that reason, pilots young and old or new to PPRuNe would be wise to find the time to browse through the old Department of Civil Aviation Aviation Safety Digests available at: https://www.pprune.org/pacific-gener...e-digital.html
The attempts thus far to replicate the value of those ASD's have never come close, finding another Mac Job might be a start.
CC
I had an engine failure in a B58 Baron once. I landed and opened the cowl. I had a look about, and didn't see anything obvious, so I decided to attempt a start.
I turned on the fuel pump, in anticipation of that - and the entire (hot) engine disappeared in fuel spray. !
All of the fuel injectors were less than finger tight. They had been replaced in the night, and the engineer was interrupted after screwing them in finger-tight, but before actually tightening them with a spanner.
I turned on the fuel pump, in anticipation of that - and the entire (hot) engine disappeared in fuel spray. !
All of the fuel injectors were less than finger tight. They had been replaced in the night, and the engineer was interrupted after screwing them in finger-tight, but before actually tightening them with a spanner.
