Date: 201301
Local time of day: 0001-0600
Location: ZZZ.Airport, US
Weather elements / visibility: 10
Aircraft: MD-82
Operator: Air Taxi
Operating under: Part 135
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: CTAF ZZZ
Reporter organization: Air Taxi
Reporter function: Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor
Human factors: Fatigue; Confusion; Situational Awareness
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Ground Excursion Taxiway
Detector: Person Flight Crew
When detected: Taxi
Result: General None Reported / Taken
Contributing factors: Environment - Non Weather Related; Airport; Human Factors
Primary problem: Human Factors

Narrative: I was taxiing slowly [after clearing the runway] while First Officer was accomplishing the After Landing Checklist and calling ATC to cancel IFR. As we proceeded onto Taxiway C; there was a question of where we were to park and the location on the airport of the FBO. The First Officer attempted to contact the FBO via Unicom; and received no reply. We taxied past two spurs leading to ramp areas before we noticed two charter buses parked on the dimly lit ramp with their running lights on. It was then that we realized we had missed the ramp entrance for parking. I stated we would continue further down the taxiway; and asked the First Officer to help determine a return route; and briefly referred to the airport diagram. Approaching the intersection of the taxiway and [the parallel runway]; I glanced and noted a large gap in the blue taxiway lights on the left side and stated that it appeared we would have room to maneuver for a 180-degree turn back on the taxiway. At approximately 90 degrees into the turn; I was startled to see that the gap in the blue edge taxiway lights was not a hard surface as I thought but frozen grass. Before the aircraft could be stopped; the nose wheel exited the taxiway. Steering in a left turn was significantly diminished; almost impossible; and Captain made the decision; the First Officer agreed; that there was adequate clearance to continue forward across an approximate 50 foot width of frozen ground onto an adjoining ramp. Parked to our right on this ramp was a citation jet; and as we neared the hard surface; two individuals exited the citation. The First Officer opened his side view window and using hand signals along with leaning out and visually clearing the right side; the aircraft was maneuvered safely past the citation with assistance from the individuals on the ground; remaining clear of the hangar on the left. While maneuvering; I was continually cross checking power settings; monitoring the First Officer's hand signals; and visually checking the aircraft's left side clearance. When the First Officer indicated it was clear to begin a right turn; I noticed another individual standing to the left near the building/hangar who had not been there prior. At no time during the maneuver onto this ramp did we see any of the individuals on the ground signal for us to stop; it appeared they were willing to help us clear the area and get back onto the ramp surface. After completing the right turn around the citation jet; we exited the ramp; rejoined the taxiway; and proceeded to the parking area without further incident.Human Factors: 1. Time of arrival was near 1 am; and even though the Captain had been to this airport one time previously flying in this type of aircraft; it was approximately two years earlier. The First Officer was unfamiliar. One of the difficulties we soon discovered with this airport; late at night during winter operations without snow cover; was the lack of distinguishing visual cues between the surface movement areas and frozen ground; especially during a very dark; overcast night. While the airport is more suited for general aviation and business aircraft; the majority of the Captain's extensive FAR 121 experience was at air carrier airports no less than 7;000 FT runway length and parking at terminal gates. However; the safe operation of an MD80 aircraft into a GA airport that was not really designed to handle this type of aircraft brings about a new set of challenges that I have little experience with. This led to a misconception of adequate taxiway clearance for a 180-degree turn in a very tight area. Under more familiar circumstances; this choice would have never been an option nor considered in favor of an alternate taxi route; even if it meant taking a few extra minutes on a circuitous taxi around the entire airport.2. The First Officer had been recently hired; had 1;800 hours total time; and had only logged approximately 200 hours in the aircraft. At my previous domestic airline; I was flying with First Officers who had significantly more total flight time (no less than 5;000 hours); who were from a variety of flying backgrounds; and who didn't need to be watched over 100% of the time and/or given instruction on a routine basis. That is not the case at my current supplemental airline. On this trip; the First Officer's lack of FAR 121 experience and minimal recency of flight experience created an environment where my attention was further divided; acting more as a flight instructor rather than as Captain/PIC; which in of itself is stressful and fatiguing. Contributing to the incident was the First Officer's lack of training/experience in CRM; and as such; deferred to the Captain's judgment without question and was not proactive enough to advocate an alternate course of action.3. Charter risk assessment. The company follows a risk assessment checklist to determine operational feasibility on charter requests. While the person(s) completing the checklist may have a pilot license; these individual(s) do not have personal experience flying the aircraft along with other demands that are placed on crew members in non-scheduled charter operations. I believe the company's risk assessment and decision to accept this charter with all its schedule changes was grossly flawed and a contributing factor. As a result; the company's decision put the crew at high risk for a fatigue related incident.4. Fatigue. A charter operation into this airport was not part of the original 3-day trip pairing assigned by Crew Scheduling late in the afternoon two days prior. In fact; even though I had requested and was promised an emailed copy; an actual itinerary for the original 3-day trip was never provided prior to our 'show time'. On the first day; our original 'show time' was 1:00 pm local; and an hour prior to that time; I received a call from Crew Scheduling advising me to show at 4:00 pm local due to a schedule change. I inquired again about obtaining an itinerary for the trip and was promised an emailed copy. Not less than an hour later; I received another call by Crew Scheduling and advised to show at 7:00 pm local. It wasn't until the crew showed at Operations/Dispatch that we were given a copy of our itinerary; which showed late evening departures of 2-leg; 4-leg; and 3-leg days ending in the early morning hours between 1:00 am and 5:00 am. On day 1; we ended the second leg at 1:30 am and arrived at the hotel around 2:30 am. I didn't fall asleep until nearly 4:00 am and was awake 3-1/2 hours later. I attempted to go back to sleep; but was still awake at 10:00 am. About an hour-and-a-half later; I met with two of the flight attendants to walk around the downtown area and eat lunch. When we returned to the hotel 3-hours later; I attempted to take a nap in preparation for our 5:00 pm departure from the hotel and a 4-leg schedule; but sleep evaded me. At 4:15 pm; Crew Scheduling called and told me to remain in the hotel until further advised due to another schedule change. At 5:00 pm I was called again and told to leave the hotel for the airport. When I asked about our schedule; I was told 'it's still being revised' and that the first leg was still a 7:00 pm (00Z) departure. On the hotel shuttle; I received a text message from Crew Scheduling advising me that an email was sent with our itinerary. At the FBO; I accessed my email account and printed out; not a modified 4-leg; but a 6-leg itinerary (3-live; 3-repositioning) that ended at 1230Z; a 14-1/2 hour duty day; which included the incident airport for this report as our third leg. At the FBO; I was concerned that; while it 'looked good and was legal' on paper; the company was overly optimistic that the schedule could be completed 'on time' given the nature of sports team charters and unforeseen delays associated with game time extensions and team transportation issues to/from the arena. My thought process was then focused on dealing with only one leg at a time; we could not control extenuating circumstances; and we would do our best to complete the schedule. After I printed out our flight release paperwork and passenger manifest; I proceeded to the aircraft; prepared the cockpit for departure; and found two items that needed to be resolved before we could depart. Even though we carried a flight mechanic on board who had gone out to the aircraft 2-hours earlier; the maintenance items caused a 40-minute delay to our departure. Before departure; the First Officer and I determined who would fly each of the legs. Because of the First Officer's low time and lack of experience in the MD80; I decided to have the First Officer fly legs 1 & 2; which were 8;000 FT or better runways; I would fly legs 3 & 4; airports with 6;000 FT runways; and the rest would be decided on later. As we began the first leg; I noticed the First Officer was making a series of small mistakes; and he didn't appear to be as 'sharp' as he had been on previous flights that I'd flown with him. Our second leg was scheduled as a short 20-minute repositioning flight (plus taxi time). Immediately after we were airborne; I scrambled to obtain arrival ATIS; contacted the FBO while continually monitoring the First Officer's flight path; but it was evident to me something was wrong. When I asked the First Officer if he was okay; his reply was that he was struggling to keep up and not accustomed to flying late evening hours. After landing and parking at the FBO; I asked the First Officer how he was feeling; and his statement was that he was feeling a bit tired; but he was 'good to go'. Personally; I wasn't noticing the effects of fatigue on myself; but in hindsight; the underlying clues were evident. By the time we departed for our third leg; which was live; and landed at 0530Z; it took less than 5-minutes for the incident in this report to occur. Had both of us been more familiar with the airport; fully rested; and operating during the hours we were more accustomed to; the incident would likely not have occurred. Instead; insidious fatigue caused impaired decision making.


Second narrative: We landed and cleared at [the first taxiway]. The Tower was closed so we had to make the announcements on CTAF that we were clear of the runway. I was able to contact Approach and cancel our IFR flight plan before turning onto the intersecting taxiway. As we continued to taxi I was able to complete the After Landing Checklist also. As we continued to taxi along; both the Captain and myself were looking for signs of where our destination would be. Most of the ramp area to the left of our path was dark and unattended. We saw some lights or what appeared to be a lighted FBO towards the end of the taxiway at the northern side of the airport. As we were passing a left turnoff we noticed two charter buses sitting in a darkened area of the ramp but the buses position lights were on. We realized those were the buses meeting the team; but we had taxied past the point were a left turn could be made into the area. We preceded northbound and I tried to establish communication with the FBO once again. An attempt to contact the FBO earlier had not been successful. The FBO; once again did not answer on the frequency and we started looking for a way to turn around. I was looking at the airport diagram and could see that we would be approaching the left runway. Understanding we would be crossing another runway I quickly started making an announcement on CTAF that we would be taxiing on the left runway. There was no reply from any other aircraft in the area and I visually scanned the runway to ensure no other traffic was using this runway. As we started a left turn in the vicinity of the runway approach area I heard the Captain mention something about being on grass. Up to this point the entire area we were maneuvering in appeared in the dark to be paved. Once the Captain mentioned the grass and I looked down over the nose I could see we had taxied off the left side of the taxiway into a grass area between the ramp area and taxiway. We taxied straight ahead into the ramp in order to get back on the pavement. On the ramp area there was space between the hangar and a parked Cessna Citation. As we approached the area two men came out of the Citation I opened my side window and via hand signals was able to establish communication with them to help me ensure that we had enough room to taxi safely by the Citation on my side. Both men gave me thumbs up and waved us on corroborating that we could safely taxi by the parked aircraft. After we passed the Citation the Captain was able to make a right turn back onto the taxiway once again and we taxied to the ramp area without further incident.


Synopsis: MD80 flight crew describes the events leading up to a taxiway excursion after a late night arrival at an airport with the Tower closed. The crew is able to maneuver the aircraft to continue across frozen ground and back onto a paved surface.