Narrative:

While opening the main cabin door from the outside; the key was left in the door lock. Our 1 passenger boarded the aircraft with my first officer. I walked around the aircraft one last time prior to boarding and did not notice the key. At about the same time as gear retraction on departure; a fluttering sound could be heard in the cabin and cockpit for approximately 8 seconds. Not knowing what the sound was; we got the aircraft to a safe altitude; then I attempted to troubleshoot and reassure our passenger. Not able to find the cause; with good WX; a calm passenger and healthy engine instruments; we pressed on to our destination of ZZZ. 10 mins after departure; I realized it might be a key when I prompted my partner to check his pockets. An aircraft key was indeed missing. We prepared for a possible single engine scenario and eventually landed safely at ZZZ. Once our passenger was safely on her way; we carefully postflt'ed the aircraft. The key had been ingested by the left engine; creating extensive damage to the first compressor and the fan case. I have learned that good key security/etiquette is not something to take for granted. I have also learned that checking every inch of an aircraft's skin is necessary on a preflight walkaround in order to minimize the chances of preventable FOD.

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Original NASA ASRS Text

Title: A FRACTIONAL C525 CAPT LEFT A KEY IN THE ACFT'S DOOR PREFLT. DURING POSTFLT; DAMAGE WAS DISCOVERED ON THE L ENG. CREW SUSPECTS KEY WAS INGESTED.

Narrative: WHILE OPENING THE MAIN CABIN DOOR FROM THE OUTSIDE; THE KEY WAS LEFT IN THE DOOR LOCK. OUR 1 PAX BOARDED THE ACFT WITH MY FO. I WALKED AROUND THE ACFT ONE LAST TIME PRIOR TO BOARDING AND DID NOT NOTICE THE KEY. AT ABOUT THE SAME TIME AS GEAR RETRACTION ON DEP; A FLUTTERING SOUND COULD BE HEARD IN THE CABIN AND COCKPIT FOR APPROX 8 SECONDS. NOT KNOWING WHAT THE SOUND WAS; WE GOT THE ACFT TO A SAFE ALT; THEN I ATTEMPTED TO TROUBLESHOOT AND REASSURE OUR PAX. NOT ABLE TO FIND THE CAUSE; WITH GOOD WX; A CALM PAX AND HEALTHY ENG INSTS; WE PRESSED ON TO OUR DEST OF ZZZ. 10 MINS AFTER DEP; I REALIZED IT MIGHT BE A KEY WHEN I PROMPTED MY PARTNER TO CHK HIS POCKETS. AN ACFT KEY WAS INDEED MISSING. WE PREPARED FOR A POSSIBLE SINGLE ENG SCENARIO AND EVENTUALLY LANDED SAFELY AT ZZZ. ONCE OUR PAX WAS SAFELY ON HER WAY; WE CAREFULLY POSTFLT'ED THE ACFT. THE KEY HAD BEEN INGESTED BY THE L ENG; CREATING EXTENSIVE DAMAGE TO THE FIRST COMPRESSOR AND THE FAN CASE. I HAVE LEARNED THAT GOOD KEY SECURITY/ETIQUETTE IS NOT SOMETHING TO TAKE FOR GRANTED. I HAVE ALSO LEARNED THAT CHKING EVERY INCH OF AN ACFT'S SKIN IS NECESSARY ON A PREFLT WALKAROUND IN ORDER TO MINIMIZE THE CHANCES OF PREVENTABLE FOD.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.