Newly minted PPL turning up at a new club for a checkout, the instructor was unavailable because during the day he had an engine failure in a twin and diverted 50nm away.
I was to fly the owner up to Cardiff in a 172 to fetch the instructor and carry out my check on the way back.
Left in a hurry, taxied in and shut down at Cardiff,
Marshaller: Hey mate, you know theres oil pissing out of the engine dont you?
I'd left the oil dipstick on the tarmac in Haverfordwest. We had to wait for another guy to fly it up to us. Three aeroplanes in a row 50 miles from base, and a film of oil over the Welsh countryside.
Very embarrassing.