ground running
Having worked on the Dart & the Tyne, yes we used to be under the engine when it was running.
With either engine in "ground fine pitch" the propellor was onle discing "ie" not producing any thrust. There was no reverse on the Dart (Viscount) but you would not be able to approach the Tyne (Vanguard) if it was in reverse.
The main difference was that the Tyne was a constant speed engine so to get the correct pressures etc you had to go to High ground idle & this was what was needed to carry out leak checks etc.
tristar 500