EMB-505 / Phenom 300
Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 60; Flight Crew Total 4200
Distraction; Confusion
Aircraft Equipment Problem Less Severe; Ground Event / Encounter Other / Unknown
Flight Crew Returned To Departure Airport; General Maintenance Action
Aircraft; Procedure; Human Factors
Shortly after the gear was retracted we noticed an unusual buzzing/vibration. It was resonating throughout the whole airframe. We continued climb and decided to troubleshoot. After not being able to identify the source of the vibration we decided it best to turn back to [departure airport] to try and identify the source. Once we landed and parked we did a walk around to [try to] find anything that could have been causing the vibration. The only thing we could find was some tape on one of two NACA scoops on the belly of the plane. This has been known in the past to cause a vibration throughout the airframe.After consulting with our mechanics we were advised to remove the tape; that this was more than likely the source of our vibration. So we refueled and refiled our flight plan and departed. As soon as we retracted the gear again the vibration was present. So we tried a few more items to troubleshoot while we were being vectored for our return to our departure airport. With this unknown vibration we felt it unsafe to continue any flying until the issue is resolved.
The reporter added that during a follow up diagnostic flight; a noise was identified in the lavatory. After landing it was discovered that the lavatory service port coupling had disconnected and cabin air was escaping through the system.
EMB-505 Captain reported an unusual vibration that resulted in a return to the field. During a subsequent diagnostic flight the noise was narrowed to the lavatory system; and later a service port coupling was found to be missing.