Turbine Inlet Temperature Sensor (Engine):
The turbine engine is basically composed of different stages of compressors, combustion chamber, turbine stages. Now, when the engine is running, the air will ingested into the engine and will be compressed through the compressor stages. After that the air will enter the combustion chamber as an element for combustion to take place with the fuel. then, the discharged hot exhausted air will leave the combustion chamber under very high in both (Pressure and Temperature). This exhausted air is used to hit the turbine (High Pressure Turbine) causing them to rotate at which in turn will rotate the compressor and so on.
It is used to measure the temperature of the discharged air coming from the combustion chamber and hitting the turbine. the sensing of this temperature is very useful to control the engine operation by the computer that is used this information and according analysis the engine combustion effeciency and at the same time control the power output of the engine automatically through a computer called ECU - Engine Control Unit -. the ECU is a computer that receives different signals from different sensors and systems of the aircraft. One of these inputs is the Turbine Inlet Temperature.
Turbine Inlet Temperature Sensor (Aircondition System):
There is also a sensor called TIT sensor installed on the airconditioning pack. The aircondition system pack. This pack composed of
1- ACM - Air Cycle Machine - (FAN, Compressor, and Turbine)
2- Heat exchangers
3- Condenser
4- Reheater.
Now, the aircondition system is controlled by computer called Pack Controller and another computer called Zone Controller. Now the engine bleed air is delivered to the airconditioning packs to be conditioned both (Temperature and pressure) in the following sequence:
1- the bled air enters the pack via a pack flow valve.
2- the hot bled air enters the primary heat exchanger to be cooled little bit before entering the ACM compressor at which the air is going to be compressed so its pressure will increase.
3- the air will leave the compressor with high pressure and very high temperature due to the compression.
4- then the air will enter the main heat exchanger to be cooled. Then the air will enter the reheater to increase its temperature so we can eliminate any water particle suspended in the air before entering the turbine - The elimination of any water particle is useful to protect the turbine blades from being daamaged or corroded-. Then the turbine will cause the compressed air to extract due to giving force for the turbine to rotate. At this point the air entering the turbine will be so hot and the air leaving is so cold.
Now the computer controlling the system operation needs input to control the flow rate of air entering the packs and also to control the air entering the heat exchangers. Also the computer needs these inputs for maintenance personal analysis and to monitor the efficiency of packs.
Turbine inlet temperature sensed will be signaled to the pack controller which in turn with another sensors signals will control the aircondition system operation.
Ayman Shak'ah
Licensed Aircraft Engineer
Showing posts with label Boeing. Show all posts
Showing posts with label Boeing. Show all posts
Sunday, September 16, 2007
Rules For Dispatching Aircraft For Next Flight
Dear All,
I would like to brief some information regarding the basics in dispatching an aircraft for the next flight. These information are as follow:
1- When the aircraft reached the destination, the pilot will register any comments, faults, warnings, observations,that occured during his flight in the ATL - Aircraft Technical Log Book-. If he has no comment then he will write down "NIL DEFFECTS". At the same time, when the aircraft reaches to the gate, the ground engineer, technician, and or mechanic will carry out walk around, and transit check. Accordingly if he observe any finding such as leak, damage, ...etc he will also report it in the ATL.
2- The Aircraft Log Book is usually has two columns. One for the Finding where to be reported another for the engineer to write down the ACTION TAKEN.
3- There is a book called MMEL "Master Minimum Equipment List" in each aircraft. The MMEL is issued by the manufacturer and approved by the Civil Authorities like FAA, EASA, CAA, ...etc. Note that any airline can make more restrictions to what is mentioned in the MMEL but can't reduce what is already in it. In this case the MMEL will become MEL - Minimum Equipment List-.
4- The MMEL or MEL is the book that has most of the faults mentioned in. It will give the minimum requirment needed for the fault to be dispatched. Like it will mention if this fault is "GO", "NO GO", or "GO IF...". In the MEL also there will be for some faults the code "M" or "O" and or BOTH. The "O" is stated for OPERATIONAL PROCEDURE while the "M" is stated for MAINTENANCE PROCEDURE. That means if this fault occurs then the Pilots have specific procedure to carry out during aircraft operation regarding that system or flight and in "M" case that means the maintenance has procedure to do before dispatching the aircraft. Please note that MEL items are categorized in dispatchable time limitation such as maybe some faults are GO item for maximum limited number of flights another are dispatcheable for maximum number of days and some them are dispatcheable in some atmospheric conditions.
5- The captain can REJECT what the engineer is saying if he felt not convinced in such dispatchable conditions mentioned in the MEL because in some cases he believe in this atmospheric climate condition he may face the next flight as he can see in the meteorology report some troubles. Anyway he can REJECT the action taken and usually in this case this issue will be reported to the MANAGEMENT so they will advice the flight crew what to do or advice the Maintenance personal of what to do. LAST DECISION WILL BE FOR THE PILOTS as they are going to fly this aircraft.
6- there are some faults that you will not find in the MEL. like LEAK. We can find the dispatchable limitation for any leak in the AMM - Aircraft Maintenance Manual - that will state the dispatchable leak limitation and according also to the leak limitation.
7- Some findings maybe like structore damage, in this case the reference will be something called SRM "Structural Repair Manual" that will give the dispatchable measurements of that damage and always we put into consideration if this damage location in pressurized or unpressurized zones on the aircraft.
So far, I hope that this briefing clarify the way of dispatching any aircraft for the next flight. At the end of each aircraft log book page, the ground engineer, or technician, or mechanic will sign certification that the aircraft is safe for the next flight and then the CAPTAIN will sign final acceptance for that aircraft to take.
Best Regards
Ayman Shak'ah
Licensed Aircraft Maint. Engineer
I would like to brief some information regarding the basics in dispatching an aircraft for the next flight. These information are as follow:
1- When the aircraft reached the destination, the pilot will register any comments, faults, warnings, observations,that occured during his flight in the ATL - Aircraft Technical Log Book-. If he has no comment then he will write down "NIL DEFFECTS". At the same time, when the aircraft reaches to the gate, the ground engineer, technician, and or mechanic will carry out walk around, and transit check. Accordingly if he observe any finding such as leak, damage, ...etc he will also report it in the ATL.
2- The Aircraft Log Book is usually has two columns. One for the Finding where to be reported another for the engineer to write down the ACTION TAKEN.
3- There is a book called MMEL "Master Minimum Equipment List" in each aircraft. The MMEL is issued by the manufacturer and approved by the Civil Authorities like FAA, EASA, CAA, ...etc. Note that any airline can make more restrictions to what is mentioned in the MMEL but can't reduce what is already in it. In this case the MMEL will become MEL - Minimum Equipment List-.
4- The MMEL or MEL is the book that has most of the faults mentioned in. It will give the minimum requirment needed for the fault to be dispatched. Like it will mention if this fault is "GO", "NO GO", or "GO IF...". In the MEL also there will be for some faults the code "M" or "O" and or BOTH. The "O" is stated for OPERATIONAL PROCEDURE while the "M" is stated for MAINTENANCE PROCEDURE. That means if this fault occurs then the Pilots have specific procedure to carry out during aircraft operation regarding that system or flight and in "M" case that means the maintenance has procedure to do before dispatching the aircraft. Please note that MEL items are categorized in dispatchable time limitation such as maybe some faults are GO item for maximum limited number of flights another are dispatcheable for maximum number of days and some them are dispatcheable in some atmospheric conditions.
5- The captain can REJECT what the engineer is saying if he felt not convinced in such dispatchable conditions mentioned in the MEL because in some cases he believe in this atmospheric climate condition he may face the next flight as he can see in the meteorology report some troubles. Anyway he can REJECT the action taken and usually in this case this issue will be reported to the MANAGEMENT so they will advice the flight crew what to do or advice the Maintenance personal of what to do. LAST DECISION WILL BE FOR THE PILOTS as they are going to fly this aircraft.
6- there are some faults that you will not find in the MEL. like LEAK. We can find the dispatchable limitation for any leak in the AMM - Aircraft Maintenance Manual - that will state the dispatchable leak limitation and according also to the leak limitation.
7- Some findings maybe like structore damage, in this case the reference will be something called SRM "Structural Repair Manual" that will give the dispatchable measurements of that damage and always we put into consideration if this damage location in pressurized or unpressurized zones on the aircraft.
So far, I hope that this briefing clarify the way of dispatching any aircraft for the next flight. At the end of each aircraft log book page, the ground engineer, or technician, or mechanic will sign certification that the aircraft is safe for the next flight and then the CAPTAIN will sign final acceptance for that aircraft to take.
Best Regards
Ayman Shak'ah
Licensed Aircraft Maint. Engineer
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