Quick Introduction to the Airconditioning Unit
In the A7-E the air-conditioning system takes high pressure bleed air and passes it through the primary heat exchanger. After here it enters compressor wheel section of the a/c unit, where the heat exchanger reduces the temperature of the bleed air.
The A7-E cockpit temperature is maintained either manually or by setting the cockpit temperature with the temperature control knob. There is cockpit over-temperature protection which is provided in automatic and manual settings, and limits the cockpit temperature to 210 degrees F. See the image below for the pictures and locations of the controls.
The air-conditioning system also provides anti-exposure suit ventilation and this is controlled separately from cockpit temperature. In my squadron very few of the pilots used anti-exposure suites, and most used wet suits when flying over cold water (less than 60 degrees F).
The anti-g suit also uses air provided by the air conditioning unit.
While airborne, with an operable air-conditioning unit, the cockpit was very comfortable. This was true for the coldest to the hottest days I experienced. Full gear was: wet suit (cold water operations), flight suit, g-suit, LPA and survival harness, helmet with visor down, flight boots, Nomex gloves, and oxygen mask on. The oxygen was conditioned and so was always cool on the face, and not uncomfortable.
There were times where the system was not quite useful. While on the tarmac was one such time, and this due to limited power on the aircraft, and hence lower pressure bleed air. Don't remember it ever getting too bad though, because we could have the canopy closed. On the deck of the carrier we were required to have our canopy open, and without much power on the aircraft, there was almost no cooling. The environment on the deck was hot. Think big asphalt parking lot in Houston with Jet exhaust everywhere. It did become almost unbearable if you were subjected to someone's jet exhaust, which got trapped in the cockpit by the clam shell canopy, burned the eyes, and made it difficult to breathe.
NATOPS Check Ride with no A/C
I flew out to Lemore from China Lake to pick up a NATOPS Check Pilot to go through my flight safety test. It was a cloudless day and warm out, but not hot. On the way there the air conditioning failed and there was no cooling or heating. The heat in the cockpit built up quickly. I decided to press on and by the time I got to Lemore my flight suit was completely wet from head to toe from sweat. It was pretty bad in the cockpit. I drank a lot of water and sat down to brief with the other pilot. I asked him if I should re-schedule the check ride and he said we didn't have to. It was an experience I don't think either one of us had had up to that point. A very uncomfortable flight, but still not unbearable. Any longer flight time would have caused distraction from the physical discomfort, and dangerous dehydration.