That date, may not mean a whole lot to you - but it was one of the Mi Amigo's attempts, to fill up with sea-water.
Thankfully, all was well - but here is a recording from my archive, in the evening & they had returned to the air. There is also in the same set, some recordings of the anniversary of the MOA - on the 14th August 1977, with Steve Kent doing the honours.
Enjoy.

https://pixeldrain.com/u/Xu8MRN7b
https://pixeldrain.com/u/Z1DYGPqC
https://pixeldrain.com/u/cRSWiBjy