Recirculation Fans OFF above +15°C
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Hello everyone,
I have a question regarding the RECIRC FANS / cabin recirculation fans.
In the official Fokker 100 AOM, Expanded Normal Checklist, section 6.02.01, page 2, under Flight Deck Preparation / Overhead Panel / Air Conditioning, it says:
“Set temp selectors as required.
Set ECON as required.
Select cabin recirculation fans OFF if OAT is above +15°C / +59°F.”
However, I am not completely sure how this should be interpreted operationally.
From the system description, the RECIRC FANS pushbuttons appear to work like this:
- Normal / blank: recirculation fans operating.
- OFF white light: recirculation fans manually switched off.
My doubt is that, later in the normal flow, the After Starting check requires the alert lights to be out, including amber and white lights. If RECIRC FANS are selected OFF, the white OFF lights remain illuminated, at least in the Just Flight simulation.
I have also watched some real Fokker 100 cockpit videos, including operations in warm climates above +15°C, and I do not clearly see the RECIRC FANS being kept OFF during normal flight. This makes me wonder whether the AOM line means:
- They should really be selected OFF whenever departure OAT is above +15°C.
- This was operator/MSN/configuration dependent.
- This is only a temporary ground/flight deck preparation action.
- The fans are later selected back ON before or after engine start.
- The Just Flight implementation of the white OFF lights makes this item difficult to apply exactly as written.
Could any real Fokker 70/100 pilot, engineer, or someone familiar with actual Fokker SOPs clarify how this item was normally handled?
I am attaching the relevant AOM page for reference.
Many thanks in advance for any clarification.
The Fokker is a fantastic aircraft and I am trying to understand this procedure properly rather than just guessing.
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The airline SOP with which I'm familiar had them off on the ground and turned them back on after thrust reduction/accel alt after takeoff. I imagine the reason for it is that the Fokker air conditioning system was not actually terribly effective and on the ground at hot airports in the summer it was very difficult to keep the cabin cool. Once you're in flight, the ambient temp obviously reduces and the air con is then much more effective.
The dark cockpit philosophy that the Fokker used wasn't absolutely rigid as far as I'm aware - it was designed so you could see at a glance if something wasn't as it normally is. But you can takeoff with white lights, as long as you know what they are and why they're on.
Hope that helps -
Fokker operator here in the climate of Australia. Well and truly we operate at 30 degrees plus at times - not a fun time at all especially with a high passenger loads cause the more bodies create heat.
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Yes when the aircraft is APU only and on the ground during passenger loading or turn arounds the RECIRC FAN are switched off because all they are doing is cycling hot heat from the cargo compartment
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Airlines have different and pilots have different times when an where to turn them off and on, I have flown with the type of Captains that have them on immediately after engine start and others who wait until the aircraft is well and truly into cruise so the system as had time to cool down. Some Captains would not proceed with engine start unless they were on after the Before Start Checklist
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Yes
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Can be engine start can be after, since you do not have real passengers it does not really matter unless you want to operate real high realism
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This is true - until some more features are in you will have to interpret the Just Flight checklist and AOM from real life differently.
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The 777 has also disconnectable recirc fans. its manuals can also give information when to operate them.