Heat and Vent Emergency

Emergency Depressurization (Intentional)

  1. Oxygen — 100%.
  2. Descend to 25,000 feet or below, if circumstances permit.
  3. Emergency ram-air lever* — Between CLOSED and OPEN.

  4. Cockpit pressure selector switch - RAM AIR ONT (emergency ram-air lever — OPEN), if resultant temperature is too cold or too hot.

    Note

    The cockpit is decompressed rapidly when the cockpit pressure selector switch is moved to RAM AIR ON or the emergency ram-air lever* is moved from the CLOSED position.

  5. Cockpit pressure selector switch - OFF, and emergency ram-air lever — CLOSED, if no airflow or pressurization is necessary.

    Warning

    During this no-ventilation condition, use 100 percent oxygen to offset the effects of possible cockpit contamination.

  6. Land as soon as practical.

    Note

    After the cockpit has been depressurized, the emergency ram-air lever must be at CLOSED (cockpit pressure selector switch moved out of RAM AIR ON position on “ other airplanes), to permit normal operation of the pressurization system.

Emergency Depressurization (Unintentional)

If sudden depressurization occurs because of a sudden stoppage of airflow to the cockpit, proceed as follows:

  1. Oxygen — 100%.
  2. Descend to 25,000 feet or below, if circumstances permit.
  3. Canopy and windshield defrost lever — INCREASE momentarily. This will determine whether normal defrost airflow is available and will offer an indication of where a possible malfunction has occurred.

  4. Normal defrost air available. If normal defrost air is available, the malfunction has probably occurred downstream of the main system shutoff valve. To minimize possible damage to equipment:

    1. Cockpit pressure selector switch — OFF (RAM AIR ON) or emergency ram-air lever — OPEN OR RAM PRESS. Either of these actions will close the main system shutoff valve.
    2. Cockpit temperature rheostat (F-100F Airplanes) — Move out of HI-FLO. This will prevent possible overspeed with resultant damage to the equipment cooling turbine.
    3. Canopy and windshield defrost lever — As needed to help maintain desired cockpit pressurization.
    4. Defrosting, anti-icing, pressurization (except cockpit), and equipment cooling — Use as necessary.

  5. Normal defrost air not available. If normal defrost air is not available, the malfunction has probably taken place upstream of the main system shutoff valve. To minimize fire hazard due to possible leakage of hot air:

    1. Bleed-air emergency switch — EMER OFF.

    Warning

    Moving the bleed-air emergency switch to EMER OFF shuts off engine compressor air and renders inoperative, or shuts off, the following: fuel transfer from the drop tanks, canopy seal, cockpit air conditioning and pressurization, ventilated suit, canopy and windshield defrost, anti-G suit, pitot boom anti-ice, £ windshield ice and rain removal, and cooling of the aft electronic equipment.

    1. Emergency ram-air lever* — OPEN OR RAM PRESS. This will allow ram air to enter the cockpit.
    2. Land as soon as practical.