Please list at least three incidents and at least two examples of aircraft being grounded in those incidents. Alternatively, please explain what you mean by "usual".I was interested in this accident from the outset when, within 24 hours, it became clear that they did not suspect any serious design problem with the plane because they did not take the usual precaution of grounding the fleet.
Could you explain how that's possible when the aircraft was not under control of the crew during that flight phase?My intitial thought was that it may well have been a crew operational error and I wondered if they had allowed the engines speed to reduce to far to enable them to spool up fast enough when power was required to maintain the glide path.
Nonsense. The reports even states the conclusion, being a restriction in the fuel supply lines.Unfortunately, that further interim report lacks enough technical depth to enable me to come to any conclusion or even make any guesses.
It doesn't imply anything of the sort.It seems to imply that the plane was in full ILS mode and the crew were leaving the systems to themselves perhaps without watching the performance as closely as I would have expected them to.
Why?I presume the HP pumps are fed by LP pumps
Cavitation evidence. I thought everyone knew that.What evidence does cavitation leave in the outlet ports?
Good observations. There's something to be concerned about when the ambient temperature is below the fuel freezing point.I think the extremely low temperatures encountered during the flight could become more significant.
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...the crew accepted an ATC request to climb to 10,600m where the ambient temperature was approximately -65C...
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Could the fuel temperature in some part of the fuel system have fallen below that indicated to the crew and eventually lead to a partial blockage?
Was that during a break you took from shooting fish in a barrel?Moderator 11 said:I have removed a post which served no iuseful purpose.
Not really Softus as aircraft regularly fly in such conditions, that's why they have FCOC's and, don't forget, that aviation turbine fuel does contain anti-icing inhibitors to ensure it doesn't freeze solid (maintains a mushy flow).Good observations. There's something to be concerned about when the ambient temperature is below the fuel freezing point.
Whilst I'm not familiar with the 777 specs in detail it would be highly unusual to just have a single fuel temp probe as they usually work in groups using discrimination logic to error check and average a value ... Actually, it's highly unusual nowadays to have one of anything on an aircraftAFAIK there is only one fuel temperature probe which is in one of the wing tanks on a 777. It was abnormally cold and who knows what could be happening elsewhere in the fuel system with a sustained ambient temperature well below the freezing temperature of the fuel...
Whilst I'm not familiar with the 777 specs in detail it would be highly unusual to just have a single fuel temp probe as they usually work in groups using discrimination logic to error check and average a value ... Actually, it's highly unusual nowadays to have one of anything on an aircraftAFAIK there is only one fuel temperature probe which is in one of the wing tanks on a 777. It was abnormally cold and who knows what could be happening elsewhere in the fuel system with a sustained ambient temperature well below the freezing temperature of the fuel...
Wing tanks would be a good choice for them though as the fuel will be at its coldest in these areas.
MW
The 777 has a fuel temperature probe located between ribs 9 and 10 of the left main tank. The probe is approximately 12.6 in from the lower wing skin and is located one rib over, approximately 40 in outboard, from the aft boost pump inlet. Because the left wing tank contains a single heat exchanger, its fuel can be slightly colder than that in the right wing tank, which contains two hydraulic heat exchangers.
Fuel is heated by the engine Fuel Cooled Oil Coolers (FCOC's) ... Primarily there to cool the engine oil but a neat side effect is that the process also heats the fuel
MW
Many aircraft are fitted with Air Cooled Fuel Coolers (ACFC's) for this very purposeIsn't there some degree of temperature control there so that the fuel is not overheated when the aircraft is in a long holding pattern over a Saudi desert airport?
Me neither, it makes no sense at all only sampling fuel temperature in a single tank ... It could leak (for instance) and be isolated from the system by the crew ... Far more usual to disperse sensors across the system.I cannot immagine there is not at least one fuel temp sensor per tank. I would also have expected there to be seperate reading software for port and starboard!
The temperature probes in the 747-400, 777, and MD-11 are located where the bulk of the fuel is coldest. However, some fuel may be colder than the fuel measured by the probes, such as the fuel that is in contact with the lower wing skin. This creates a temperature gradient in the fuel tank from the wing skin to the location of the probe.
As fuel travels to the boost pump inlets, the bottom, cold layer flows through small flapper valves located on solid tank ribs next to the bottom wing skin. These valves are used to control fuel slosh. Thus, the cold fuel tends to flow toward the boost pump inlets. Because the probes are located near the bottom of the tank, the temperature reading is representative of the critical fuel temperature in the tank.
... where does it say that a probe is only fitted to a single tank as that would be really odd?
MW
And of the 747-400On the MD-11, a fuel temperature probe is located in the outboard compartment of tank no. 3 and another is in the horizontal stabilizer tank
The temperature signal originates from a single resistance-type temperature probe located within the no. 1 main tank. The temperature probe is mounted on the rear spar approximately 8.5 in off the bottom of the tank and approximately 40 in outboard of the aft boost pump inlet.