During landing gear retraction, the pilot heard a loud “bang,” and the gear unlock annunciator remained on. He placed the landing gear handle in the “down” position, confirmed three green gear-safe annunciators were on, and made a safe landing.

The technician discovered a broken ground wire at pin F of the main landing gear uplock microswitch (P/N H11-1307-1) connector. The broken wire caused the left main gear uplock to close and lock before the landing gear was fully retracted. This action resulted in the uplock housing assembly and uplock mechanism to be smashed by the retracting landing gear.

He suspects the wire broke due to age.

The submitter recommends that all operators of Cessna 650 Citation aircraft inspect the main and nose landing gear uplock microswitch connectors.

Part total time-7,556 hours.