A-7 Former Drivers/Mechanics
Hoping to get clarification on flamed-out engine instrument displays. Specifically N1 and N2 readings. Ques: If splines of the HP compressor front shaft failed from wear, allowing the shaft to disengage from mating high speed gearbox drive shaft-resulting in loss of drive mechanism to high speed gearbox and gearbox driven fuel, air, and ignition. Based on the aforementioned, could a pilot expect to see positive N1 indications and a consequently false impression that catastrophic engine failure has not occured, and thus leading to several feeble attempts to re-light. For the most part, do pilots assume that if there are negative N2 indications, then there is a greater likelihood of severe damage.