
It's that time of year...last year the big project was a landing gear overhaul. This year the big focus is the engine's "hot section" inspection which will be the first one since my airplane left the Canadian Forces. A "hot section" inspection is called for at regular time intervals per my FAA Inspection program, a program largely based on the Canadian military and Rolls Royce maintenance schedule. Many of you know the gist of it, but in a nutshell Rolls Royce Nene 10's hot section consists of nine combustion chambers aka flame tubes/burner cans. A "hot section" inspection will require maintenance technicians to remove each of the nine annular flame tubes (the shiny silver tubes exposed on front half of fuselage in the above pic), disassemble them, inspect inner and outer liners for among other things, cracks, warping, damage, blocked cooling holes and corrosion. They'll also remove igniters in the two burner cans that have them, as well as the fuel nozzles which will no doubt have "coking" or carbon/soot buildup. Here's a pic of "coked" fuel nozzles from a previous annual inspection.

The fuel nozzles will be cleaned, inspected and tested for proper spray pattern which give us a happy, even flame pattern which prevents combustion chamber hot spots, cracking or the worst scenario, an uncontained burner can failure and resultant uncontained engine fire. If any of the burner cans has any compromised areas within certain tolerances, they can be repaired and returned to service. Below is a disassembled burner can/flame tube.

Once all the inspection points and necessary repairs are accomplished, the engine will be reassembled, ground run, checked for leaks as well as confirming achieves required rpm for a given, exhaust gas temperature (EGT), outside air temp and field elevation.