Thanks to Airpig and TEEJ for the videos and for correcting my poor memory. Yes it was an SU27. That type is an important part of another air display experience I will never forget. The SU27 carried out the usual spectacular display at the Yeovilton Air Day some years ago. After it landed I wandered round to the visitors parking area to have a look at it. I took the pilot to be a very grumpy, scruffy sort of guy in a blue overall. He borrowed a ladder and leaned it against the leading edge of the port wing. He climbed the ladder and opened a hatch in the top of the wing and started tugging angrily at whatever was inside. He pulled out what looked like small supermarket bags and threw them onto the ground. Eventually, after a lot of tugging he pulled out a coiled up length of hose and, after throwing that on the ground he descended back down the ladder. It appeared that this hose was an adapter which enabled them to connect some vital service to the NATO system. Once the hose was finished with, he returned the hose and plastic bags the hatch and closed the lid.
He then placed the ladder under the nose wheel area and started another vigorous tug of war with something inside the nose wheel arch.It turned out to be a folded up tarpaulin, which he refolded and replaced. I couldn't get over the fact that all of these objects were in place during his extremely energetic display with lots of negative G.
Having replaced everything he got on board and taxied out. I set my scanner to the appropriate UHF frequencies and listened in to his various conversations with London Military. The last I heard was a frantic controller pleading with him to descend back down to the altitude to which he had been cleared.
Sadly you don't get anything like that at the Yeovilton Airday anymore.