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As was told earlier, the early model wing tanks could be purged with CO2 after they were empty to reduce the risk of fire. In an emergency, in the event of hydraulic loss, the landing gear could be lowered with CO2 also. The handles to do both were in close proximity to each other. The problem was on at least one occasion, the pilot pulled the wrong handle and accidentally lowered his gear in combat. Once the gear was lowered in such a way it could only be raised after landing. Boone Guyton relates how he as a test pilot should have foreseen this happening and had the handles positioned away from each other.
A FG-1D Goodyear built Corsair I maintained in the past, now part of the late Paul Allen’s mothballed collection, had a gear up issue relating to the Blow Down CO2 system.
It was stationed at Glenview with a reserve squadron in 1949 IIRC. A weekend warrior was flying it in a formation when he was warned his tailwheel was extending. The Pilot looked around and grabbed the hand pump and pumped the gear back up. Pilot soon noticed cowl Flaps were also extending as well as the tailwheel as his wingman radioed again. He then turned for home.
Upon arriving back at base he attempted to lower the gear, the mains now as the TW was out. The mains wouldn’t lock down and his wingman confirmed. After trying the hand pump the MLG still wouldn’t lock down and just trailed. The pilot finally tried the Blow Down CO2 which released a cloud in the cockpit without moving the MLG down.
With nothing else available the pilot landed and the still trailing gear returned to the gear well and the FG1D slid down the runway where it stopped, sitting on the extended TW and bottom of the wing.
Minimally damaged, it was repaired. Ultimately a couple years later it was transferred to the Naval Air Factory under the approach to Philly where it served as an instructional airframe in the service of training mechanics.
In with the paperwork we had was a couple official pages, one being an engineering report on what had failed and the other was a, you’ve been a bad, bad boy, report critical of the pilots actions.
Under the- Know Your Aircraft- universal Pilot theme, This Pilot Didn’t.
On the early series of the Corsair type the Tail Wheel and Engine Cowl Flaps were spring loaded in one direction and moved by Hydraulics the other. With a lack of Hyd Pressure the TW would extend as would the Cowl Flaps.
The Hyd Reservoir has a pipe that extends up from the bottom a ways. The pipe supplies Hyd Fluid to the Engine Driven Pump. The inlet to the hand pump sits on the very bottom of the Hyd Res. This way if you drain the system under normal operation the hand pump has enough to pump the MLG down. That is unless you Brain Fart, and pump that fluid out as well, which this guy did.
Having depleted all the Hyd Fluid you still have the Blow Down System to extend both MLG Legs. However, the CO2 Cannisters are removed and weighed every 30 days to ensure that they are charged and not empty should you require them. That meant the nut on the end of the Alum Hard Line is loosened to remove and reattached and tightened after the Cannister is proven to be charged by weighing it. The many times this was done ended up creating a crack in the line where it was flared. In this case, when the Pilot’s last chance to get the gear down resulted in the pressurized gas escaping when the crack line broke.
The report found that an O-Ring split in a MLG Door Actuator in the wing. Over time the Main Hyd System pumped the fluid out and started to loose pressure. This resulted in the TW starting to deploy which the wingman noticed. The importance of this was lost on our Pilot. At that point the correct response would’ve been to break formation, extend the gear and see if you could get partial Flaps and head home before all your Fluid was lost. If the gear didn’t fully extend at that point, it moves against the wind so it won’t lock down with out a push in the actuators, then wait till you’re near the base and use the hand pump to get the gear down. Then try for some/more Flaps if you can.
This guy didn’t know the systems and didn’t follow SOP for the situation that developed. In a corner with one way out a MIF then occurred.
When I worked on this one I had noticed some scrapes on the lower gear legs and the heads of a couple Clevis Bolts, like they had drug across the ground. It was later i found the paperwork and realized those scrapes were from this gear up event. The gear legs were dangling with no way to be locked down.
