High cabin altitude incidents?

[tonytales]

Regarding over-pressurizing L-1049 Constellation. At LASI New York, then KIDL and later KJFK) we came close to experiencing what happened to the TWA aircraft. It was a military WV-2 Warning Star radar Constellation. On the post-check runup we did a pressurization test. Aircraft had a max differential of 11.7 "/Hg with a relief valve setting of 12.4 "/Hg.
Pressurization was controlled on the "260" panel aft of the F/E desk. The differential pressure gauge and the controller got outside ambient air pressure through a static port located under the sliding cockpit entrance door. It was of the "salt shaker" type, that is there were a group of small holes drilled in a disk set into the skin.
So we did the runup and then set off on pressurization using the manual "star valve" control. It is fairly slow to get up there and we found we could not get above about 5 "/Hg. The problem was quickly found. The pressure relief valve mounted on the rear pressure bulkhead was wide open preventing an increase in cabin pressure. It was adjusted using an allen wrench but we couldn't get above about 7 "/Hg.
I went up and down the cabin looking for leaks - nothing bad at all. I returned to the cockpit and reported. I was standing next to the radio rack and I heard a loud hissing sound. A small instrument type flex hose was hanging loose. The PB-10A autopilot amplifier was missing but not needed for the runup. I put my finger over the hose fitting opening and joked that maybe it was all going out here. The Lead Mechanic at the F/E desk let out a loud cry. When I capped the little line the differential pressure gauge needle snapped over to the maximum reading, way above allowable.
The loose line was a static pressure hose feeding the autopilot for the "altitude hold" function. Same static port was used as for cabin pressure indication and control. Those small "salt shaker" holes caused a back pressure leading to false reading on the diff gauge. I know what a rapid depressurization looks like, dense vapor in the cabin and also how it feels like - badly hurting ears and noses. We reported it and they came up with an absolute pressure gauge we carried up on every pressurization runup. Later, an SB changed the "salt shaker" static port to a single large hole.
I saw the TWA Connie. It split open from the right aft corner of the nose wheel wll back to the wing. Inverters were dangling from electric cables, floor collapsed, awful. I believe they encountered the situation but in a commercial airliner with lots more hours and cycles than our WV-2. Also I believe that the cabin superchargers just couldn't raise it any more for the relief valve was closed. We must have been right on the edge though. The WV-2 received a special inspection but no damage was found.