G200 flight crew reported experiencing engine vibrations just after climb level-off at FL380 resulting in a return to the departure airport.
Synopsis
G200 flight crew reported experiencing engine vibrations just after climb level-off at FL380 resulting in a return to the departure airport.
Narrative
As part of our crew brief on the ground I had briefed in the event of an emergency we would return to ZZZ. Departed ZZZ with a normal takeoff and climb. We had just leveled off at 38;000 feet approximately 90 miles northwest of ZZZ [VOR] on course when we noticed that the vibrations on the left engine were all the way to the top of the caution (amber) range. As we continued we could clearly detect slight vibrations physically which reinforced the fact that this wasn't just a sensor problem. I reduced the power to about 50% before indications decreased into the normal (green) range. It was evident we could not continue so I passed the controls to my First Officer while I called the company chief pilot to advise him of our situation and we agreed that it was best to return to ZZZ as it was 90 miles closer than any other suitable field and only 20 minutes away. I took the controls back and FO coordinated a clearance back to ZZZ while I briefed our passengers over the PA. ATC initially had us descend to 31;000 then 24;000 feet direct to ZZZ1 [VOR] for the ZZZZZ arrival. As I began a gradual descent I noticed that the vibrations on the left engine were beginning to creep back up close to the caution range even as I had gradually reduced the thrust to idle. During this time ATC recleared us direct ZZZZZ1 for the ZZZZZ1 arrival. As we neared ZZZ it was evident with the ATC environment and our issue with the left engine it was best to just request priority handling. Shortly thereafter ATC gave us a discreet frequency and cleared us direct to ZZZ. As we reached 10;000 feet and 30 miles from the field I decided to just disconnect the autopilot and shut down the left engine. Throughout the whole period FO had continued to keep ATC informed and run our emergency checklists to make sure we stayed ahead of any potential problems including operating the FMS and updating aircraft flight parameters on the flight control panel. For my part I maintained a slow steady descent all the way down to the runway to make the aircraft easier to control. ATC did their part too by offering us an easier runway for landing Rwy XXR putting us on a 45 degree angle to final instead of a longer left closed pattern to Rwy Y the active runway at that time. Fortunately the weather was VFR and I was able to fly visually down to touchdown. The landing and taxi back to the FBO was uneventful with the fire department close behind us to parking. We were grateful for everyone's help and we kept our passengers informed every step of the way.
Second reporter narrative
As part of our crew brief on the ground Person A had briefed in the event of an emergency we would return to ZZZ. We departed ZZZ with a normal takeoff and climb via RWY XX on the ZZZZZ dep. We had just leveled off at FL380 aprox 90 miles NW of ZZZ [VOR] when we noticed that the vibrations on the L engine were all the way to the top of the amber (caution range). We detected slight physical vibrations which reassured us that it wasn't simply an indication issue. Person A then reduced the power to about 50% before the indications receded back into the green band. We elected to not continue under this condition; so Person A passed me Controls while he informed the chief pilot and passengers that we were returning to ZZZ. As we began the decent it was noted that the vibrations were beginning to creep back into the amber range as the thrust was slowly reduced to idle. It was evident with the ATC environment and our issue with the L engine (severe vibrations) it was best to request priority handling. Shortly thereafter ATC gave us a discreet frequency and cleared us direct to ZZZ. As we reached 10Kft and 30 miles form the field Person A decided to disconnect A/P and shutdown the left engine as the vibrations continued to penetrate the amber range at idle. During this time I kept ATC informed as well as ran emergency checklists to ensure we stayed ahead of the problem. Person A maintained a constant rate of descent all the way down to the runway. ZZZ approach assisted in the situation by offering us a straight in visual to RWY XYR as opposed to a left pattern to RWY Y. It was VFR; we landed and taxied back to the FBO non eventfully with the emergency vehicles in tow. Everyone's help was greatly appreciated in this matter.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.