Backfire tests of an aircraft piston engine

In order to solve the problem of one aircraft piston engine that the backfire test must be conducted to acquire the airworthiness type certificate (TC) pursuant to article 33.51 of part CCAR-33 "Airworthiness standard of aircraft piston engine", a new test method was proposed based on the photoelectric signals through the study on single-cylinder engine. The experiments showed that the proposed method can well detect the backfire. Based on the above research, the inducing backfire method was conducted through reducing the flow rate of fuel by operating lean/rich joystick. The experiments on the tested engine show the engine is tendency to backfire in its operating conditions and the engine works well after 57 times artificial induction backfire on the tested engine. The tested engine meets the requirements of airworthiness certification.