Light Transport; Low Wing; 2 Turbojet Eng
Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor
Flight Crew Last 90 Days 90; Flight Crew Total 12000; Flight Crew Type 90
Time Pressure; Workload
Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Weather / Turbulence
Flight Crew Took Evasive Action
Human Factors; Weather
During a very busy approach I inadvertently descended to a lower altitude too soon. After holding for approximately 40 minutes our flight was being vectored for an approach to [our original destination]; for the second time we were given a different heading and told all approaches to our airport and some surrounding airports were not available. We were in rough air due to significant rain at approximately 3;000 MSL; the approach controller suggested KMKY and we agreed; however the First Officer was unable to program a new destination in the box (FMS). We were close to the airport with wind shifts on the ground; we accepted the VOR DME 17 due to the winds and it was a raw data approach that we could do without programming the FMS. I descended to 1;500 MSL according to our clearance we both setup the VOR and inbound course and due to the rough ride and the aircraft not responding quickly to autopilot commands I disconnected the autopilot. I did not want to look away from the instrument panel so I asked the First Officer when I could continue my descent; he replied I could go down now to minimums. We broke out of the clouds with an obstacle slightly left of our course; I deviated around it. We both saw the runway at approximately 4 miles and landed without incident. After landing and shutdown I looked at the approach plate and saw the crossing restriction and the obstacle. My FO stated he completely missed it when I asked. We were very rushed and surrounded by heavy precipitation after holding and being vectored to destination only to be broken off we should have either taken more time or gone to a different airport or made sure we were not so rushed. We both learned a valuable lesson that day and spent some time reviewing the programming of the FMS and the approach plate.
Light turbojet Captain reported diverting to MKY due to weather but the First Officer is unable to change the destination in the FMC. The Captain elects to fly the raw data VOR DME Runway 17 and hand flown due to the autopilot not handling the turbulence well. The First Officer was queried as to when to begin descent to MDA; and incorrectly stated now outside FIGOX.