Det är Ram luftinloppskanalen för kabinsluftsystemet. Det fungerar normalt som kylluft för förpackningarna men kan även användas som en alternativ ventilkälla i en nödsituation.
The cooling efficiency of each air conditioning pack is enhanced by ram air cooling via a heat exchanger. Ram air enters through an inlet at the abse of the vertical stabilizer and passes through the pack heat exchangers and then exits overboard. In case of failure of both packs, ram air can be used as the sole source of ventilation. This is accomplished by opening the ram-air valve via the RAM AIR switch. Ram air then enters the occupied areas through the normal vents.
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