I might have asked about this before, but have forgotten responses.
The A & P flat out despises the idea of creating a hole in my aircraft's floorpan installing tube for ashes to disperse.
My pilot window is too small to use, unless I process the remains into very fine particles and pour into dry chemical fire extinguisher which I would the vessel charge with nitrogen.
Attaching a hose to be extended to outside the window of the plane and fastening that at the pilots window, fixing the extinguisher securely to pilots seat, pull pin at desired location and discharge in 10 seconds.
No special modifications required, I could receive box of cremains, process ( perhaps 25) of them in one day's time and ship system to whomever for a fee allowing them to provide last flight.
I laughed at I think it was Neil Armstong's story of he and another pilots disaster trying to perform this duty for a friend.
Thoughts, anyone ?