C650. AFTER A PHASE MAINT INSPECTION OF THE ACFT; 2 PANELS ABOUT 2 FT BY 4 FT WERE LEFT OFF THE ACFT. AFTER MAINT; 3 FAA MAINT INSPECTORS; 4 COMPANY MAINT INSPECTORS AND 8 PLTS DID NOT DETECT THE MISSING PANELS.

Narrative

THE ACFT CAME OUT OF A MAINT INSPECTION; WAS FLOWN 30 MINS AND WENT FOR AN FAA PART 135 RAMP INSPECTION BY 3 FAA MAINT PERSONNEL AND 4 COMPANY MAINT PERSONNEL. THE ACFT THEN FLEW 6 LEGS AND 6 HRS WHEN WE RECEIVED A CALL FROM THE MAINT FACILITY SAYING THAT THEY HAD FORGOTTEN TO REPLACE 2 PANELS; 2 FT BY 4 FT IN SIZE ON THE BELLY OF ACFT. THE ACFT FLEW 7 LEGS WITHOUT INCIDENT AND WENT UNNOTICED BY 3 PLTS; 4 MAINT PERSONNEL; 3 FAA MAINT PERSONNEL; 1 FAA OPS INSPECTOR; THE MAINT FACILITY A&P AND INSPECTOR. PANELS WERE SHIPPED AND REPLACED WITH NO DAMAGE OR INCIDENT. SUPPLEMENTAL INFO FROM ACN 609791: PLANE WENT THROUGH A PHASE INSPECTION AND WAS RELEASED BACK INTO SVC. I PREFLT INSPECTED THE ACFT AND DID NOT FIND ANYTHING OUT OF THE ORDINARY; AIRPLANE PERFORMED FLAWLESSLY. THE ACFT WAS SUBSEQUENTLY INVOLVED IN A PART 135.299 RIDE WITH THE FAA AND A PREFLT INSPECTION WHICH INVOLVED SEVERAL FAA AND OUR OWN MAINT PERSONNEL. AIRPLANE FLEW A TOTAL OF 7 LEGS UNTIL WE WERE INFORMED BY THE MAINT FACILITY THAT THEY HAD NEGLECTED TO REINSTALL 2 LARGE (APPROX 2 FT BY 4 FT) PANELS ON THE UNDERSIDE OF THE ACFT. ACFT WAS GNDED AND PANELS WERE REINSTALLED. THERE WAS NO DAMAGE NOR WAS THERE ANY DIFFERENCE IN THE WAY ACFT HANDLED. PANELS ARE ALMOST IMPOSSIBLE TO SEE UNLESS YOU GET ON THE GND DIRECTLY BELOW THE ACFT CTR SECTION. NEXT TIME I'LL BE MORE OBSERVANT ON A PREFLT; SPECIFICALLY IN UNEXPECTED PROB AREAS.