Crack in the tail pipe
This is about a 'tail pipe' damage that occurred in a medium lift twin engined helicopter. This component is not the exhaust pipe of the engine, but a part of helicopter airframe and is positioned at the end of engine exhaust to facilitate smooth outflow of the exhaust gases. In fact it is a rolled, welded metal sheet for the purpose.
Now the meat part.
There was a one inch crack detected at the end of this pipe during a turn around servicing (the welding had given away). The discussion was "How bad things would get if the helicopter was flown back to the repair depot with the known fault still existing". Though legally I agree that it cannot be a good decision, nevertheless following implications were considered, had the decision to fly back to repair depot was accepted:-
1. Owing to in-flight vibrations and pulsating aerodynamics this crack may have propagated resulting in exhaust gases contacting the helicopter structure and thereby leading to a possible fire hazard.
2. Turbulent air flow so developed in the downstream of the tail pipe may result in upstream instability leading to an unstable operation of the engine.
That's how far I could see.
Any more possibilities, comments on the implications please.
Thanks for the read anyway.