3 Greens
Not all that it seems.
I had completed a rocketry mission in a Mustang at Green Hills and was landing into the north-east on runway 03. Immediately after touch down the aircraft settled a little to the left and started to swing in that direction. I applied rudder and right wheel brake to keep straight. This momentarily corrected things but I found further increasing brake necessary. Eventually very hard braking started to tip the nose over. I gave up when the prop started to hit the runway and just let it all happen after that. There was nothing more I could think to do as it was now obvious that the left undercarriage leg had folded. It all seemed to happen quite slowly as the aircraft settled onto the left wingtip off the runway and swung around until it was going sideways. I expected the right gear to collapse as it was making a deep groove in soft ground as the aircraft slid towards a large stormwater open ditch. I prepared to exit the cockpit in a hurry if it should end up in the ditch and braced myself for the expected impact, however the aircraft stopped just short of that ditch.
Finding my radio still active, I pressed the transmit button and called to advise that I had parked my aircraft in an unusual place. The response was that emergency services were on their way. I continued to sit in the cockpit wondering whether I had really checked for three green lights in the undercarriage indicator as is the normal drill on turning on to base leg. I was sure I would have but could not be certain. Right now there were indeed three greens indicating. The fire tender promptly became bogged in the soft ground near the aircraft as I climbed out onto the wing and waited for more appropriate transportation away from my unusual parking position.
Investigation revealed a failed end bearing on the rod which connects the top of the oleo to the hydraulic actuator. The rod pulls the oleo into the down position so that the broken bearing left the main leg swinging in the breeze. The down indicating micro switch is actuated by the connecting rod so that it was confirmed that I would indeed have had a valid down indication of undercarriage.