Hi,
Is this man ( below) any relation to your  family? (  in 1939 )  I thought I'd post it just  in case  he is and you don't have the articles. Same name  as your great uncle ( Marshall  the brother of the flight  sergeant  below ) and same area  they are from (Ballyclare)
The W Gillespie they mention   , is a William going by the  other newspaper reports on  there .(these ones  are from the Irish  Newspapers Archives  )
     
Irish Independent Thursday, August 10, 1939 , Page: 7 :
KILLED IN Bomber Crashes In Yorkshire
AN Irish airman, Flight-Sergt. E. J. B. R. Gillespie (26), Ballyclare, Co. Antrim, and three other R.A.F. men were killed when a bomber crashed early yesterday morning at Tollerton (Yorkshire) shortly after it had taken off to take part in the great air manoeuvres which are to continue over . England until to-morrow.'More than 1,300 machines are participating.
He was a son of Mrs. Gillespie, Mill Road, and brother of Mr. W. Gillespie, a member of Ballyclare Urban Council, and of Mr. Marshall Gillespie, a well-known Ballyclare farmer. The names of the other dead are:— Sergt. D. J. Wood, Dagenham, Essex; Aircraftman P. H. Cook, Yorkshire, and Aircraftman T. W. Clarkson, Durham. Aircraftman W. G. S. Harkness, of Castle Douglas. Kirkcudbrightshire, Scotland, was slightly injured. The machine had just risen when its starboard wing Up struck a lone tree and the 'plane _turned over on its back and crashed.
Kind regards 
Ps  editied to add If it's  the same family as yours there are a few other articles about the accident in the papers  . The other long newspaper article   about the accident mentions  that he joined  the RAF 10 years  ago ( so around 1929 he would have joined up, he would have been around only  age 16, or maybe 17 when he joined ). They also mention he was also a noted local athlete. And also mention his brothers ( William and Marshall) had left last night to attend the inquest.
Kind regards