A320 fuel/oil smell just after startup
; after start up sequence, when:
.
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Similar to farting downwind...
Following is a more technical explanation...
YouTube - Captain Bruce goes Cropdusting ed
Following is a more technical explanation...
YouTube - Captain Bruce goes Cropdusting ed
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I thought that at first, but then i thought before posting "Surely, there couldn't be a problem like this on what is the world's most popular commercial airliner,
Sorry....couldn't resist.
"Oils smells from the APU can also come from people not following the securing checklist properly. The batteries shoud only be switched off when the APU door is closed. Do it before and oil from the APU can be sucked into the ducting (not sure why) giving an oil smell when the APU bleed is on. This is of some concern as engine oil fumes are toxic."
"Reference please? Mine is the Airbus AMM and TSM (Air maintenance and trouble-shooting manuals)"
FCOM 3.03.26 p1. Securing the aircraft:
BAT 1 and 2........................................................... .....OFF
Wait until the APU flap is fully closed (about 2 minutes after APU AVAIL light goes out) before switching off the batteries. Switching the batteries off before the PU flap is closed may cause smoke in the cabin during the next flight.
"Reference please? Mine is the Airbus AMM and TSM (Air maintenance and trouble-shooting manuals)"
FCOM 3.03.26 p1. Securing the aircraft:
BAT 1 and 2........................................................... .....OFF
Wait until the APU flap is fully closed (about 2 minutes after APU AVAIL light goes out) before switching off the batteries. Switching the batteries off before the PU flap is closed may cause smoke in the cabin during the next flight.
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From the 319 FCOM...
"Turn APU BLEED OFF just after Engine Start to avoid ingesting engine exhaust gases."
After engine start the bleed air supplied to the cabin for air conditioning and pressurising will come from the engines and no longer from the APU. How will keeping the APU bleed air on ingest fumes into the cabin?
"Turn APU BLEED OFF just after Engine Start to avoid ingesting engine exhaust gases."
After engine start the bleed air supplied to the cabin for air conditioning and pressurising will come from the engines and no longer from the APU. How will keeping the APU bleed air on ingest fumes into the cabin?
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With bleed valves shut and whether packs are on or off, the piping will still retain a little of the contaminated air and send it through when the valves are reopened after start.
I agree that tailwind components are the most likely cause of the offending ingestion A surge from the fiery end has been known to travel upstream to the HP bleed stages and beyond.
Blah blah blah.....
Before jet engines were trusted with supplying clean cabin air, turbo-compressors were used for cabin air back in the days of the 707. The arrangement was a turbine fed by engine bleed air connected to a compressor with its own fresh air intake for the cabin.
I agree that tailwind components are the most likely cause of the offending ingestion A surge from the fiery end has been known to travel upstream to the HP bleed stages and beyond.
Blah blah blah.....
Before jet engines were trusted with supplying clean cabin air, turbo-compressors were used for cabin air back in the days of the 707. The arrangement was a turbine fed by engine bleed air connected to a compressor with its own fresh air intake for the cabin.
What goes around, comes around! 
Now that turbine engines are no longer trusted to supply clean air, the 787 has been designed with electric compressors for pressurisation. In fact the only bleed system on board is engine cowl heat. Wing heat and start are electric also.
Now that turbine engines are no longer trusted to supply clean air, the 787 has been designed with electric compressors for pressurisation. In fact the only bleed system on board is engine cowl heat. Wing heat and start are electric also.
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@Dream747,
I'm not familiar with the engines installed on the Airbus 320 series, so correct me if I am wrong.
The engines when running at idle supply less pressure than an APU.
Leaving the APU bleed on ,while engines on, will only keep the check-valves in the engine bleed supply ducting closed.
The apu will still be suplying all the air into the packs.
It's why an engine cross bleed start requires adding power on the engine already running to obtain sufficient start pressure.
IFIX
I'm not familiar with the engines installed on the Airbus 320 series, so correct me if I am wrong.
The engines when running at idle supply less pressure than an APU.
Leaving the APU bleed on ,while engines on, will only keep the check-valves in the engine bleed supply ducting closed.
The apu will still be suplying all the air into the packs.
It's why an engine cross bleed start requires adding power on the engine already running to obtain sufficient start pressure.
IFIX
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I notice that the cabin lights flicker after one of the engines begins to spool up during start-up which I suppose the reason for this being the engines powering the aircraft systems, taking over from the APU. What kind of systems govern such a transfer of power from different sources? I can imagine it must be pretty efficient to immediately transfer power to the APU once the pilots cut off all the engines at the gate.
Correct me if I am wrong, the power for these supplies from the engines will only be available when the gearboxes in that particular engine are driven at a sufficient speed. I suppose different engines drive gearboxes of different purposes and usage, can they be driven by any other means should a particular engine fail?
And what do these gearboxes drive? Alternators and such?
Many thanks guys!
Correct me if I am wrong, the power for these supplies from the engines will only be available when the gearboxes in that particular engine are driven at a sufficient speed. I suppose different engines drive gearboxes of different purposes and usage, can they be driven by any other means should a particular engine fail?
And what do these gearboxes drive? Alternators and such?
Many thanks guys!
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The flickering you see during start up and shut down is the load being switched from engine to APU generators and vise-a-versa. Power is usually switched at the gate to ground power so the APU can also be shut down.
The engine generators will automatically drop off line as they slow down and the output falls out of spec. The arrangement on most aircraft has the AC power switched to the next available source automatically.
Windmilling engines can supply hydraulic and electrical needs depending on airspeed and type.
The engine generators will automatically drop off line as they slow down and the output falls out of spec. The arrangement on most aircraft has the AC power switched to the next available source automatically.
Windmilling engines can supply hydraulic and electrical needs depending on airspeed and type.
