Small Transport; Low Wing; 2 Turbojet Eng
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor
Flight Crew Last 90 Days 166; Flight Crew Total 26925; Flight Crew Type 1233
Situational Awareness
Ground Excursion Taxiway
General Maintenance Action
Airport; Human Factors
I was the second in command on a charter into Bermuda Dunes airport in California. We landed on Runway 28; the aircraft was being flown by the PIC. After landing we exited the runway on a taxiway prior to the end of the runway. Once clear; I began to run the after landing checklist and was activating controls and switches as the pilot in command taxied the aircraft. As the PIC turned onto the parallel taxiway to proceed to the FBO; PIC started the turn slightly early and the left main landing gear departed the prepared surface into soft sand. We stopped the aircraft and evaluated the situation. It was determined that we needed assistance from airport personnel. Experts on the field in conjunction with our company determined the best plan of attack was to pull the aircraft back onto the prepared surface and tow it to the FBO. A plan was made with our Operations department; Maintenance; and the airport personnel who had experience pulling aircraft from the same location previously. The aircraft was safely returned to the asphalt and towed to the FBO where a qualified Maintenance Technician who was hired by our Maintenance department; inspected the aircraft and returned it to airworthiness status. Bermuda Dunes has a history of aircraft getting stuck turning onto the parallel taxiway and I was told that two other airplanes had already met the same fate in the sand this year that we were faced with. An evaluation should be made of the Bermuda Dunes airfield and notes placed in the Jeppesen plates; to alert aircrews of the hazardous situation that exists with narrow taxiways and a lack of turning fillet areas to prevent departing the prepared surface at Bermuda Dunes.
First Officer and Captain reported a taxiway excursion while turning onto the parallel taxiway at UDD.  Reporters were told; this is a common issue at the airport.