§29.1125 Exhaust heat exchangers

For reciprocating engine powered rotorcraft the following apply: (a) Each exhaust heat exchanger must be constructed and installed to with stand th e vibration, i nertia, and ot her l oads t o whi ch i t would be subjected in operation. In addition: (1) Each exchanger must be suitable for continued operat ion at hi gh t emperatures and resistant to corrosion from exhaust gases; (2) There must be m eans for inspecting the critical parts of each exchanger; (3) Each exchanger m ust have cool ing provisions wherever it is subject to contact with exhaust gases; and (4) No exhaust heat exchanger or m uff may have st agnant areas or l iquid t raps that would in crease th e p robability o f ig nition o f flammable fluids or vapours t hat m ight be present in case of t he failure or m alfunction of components carrying flammable fluids. (b) If an exhaust heat exchanger is used for heating ventilating air used by personnel – (1) There m ust be a secondary heat exchanger between the pri mary exhaust gas heat ex changer an d th e v entilating air system; or (2) Other m eans m ust be used to prevent harm ful cont amination of t he ventilating air.