Incident Overview
The crew of N79771 was cleared to taxi to Runway 4L via the outer taxiway. While taxiing, the captain became disoriented and thought the airplane was on the inner taxiway. He communicated his concerns to the first officer, whose attention had been on cockpit duties. The first officer also believed they were on the inner taxiway. In reality, the airplane was on the outer taxiway.
Actions Taken
Believing they were on the inner taxiway, the captain decided to turn left at Taxiway 'G' to return to the outer taxiway. However, when the turn was executed, the airplane was on a short taxiway that led directly to Runway 4L.
Observations
A B-737 was in the process of takeoff roll on Runway 4L. The pilot of the B-737 reported observing N79771 on the runway. Several tower controllers also stated that N79771 was on Runway 4L and made a turn off the runway. The pilot of N79771 said he saw the runway edge lights and was able to turn the airplane before entering the active runway.
Equipment Factors
N79771 was not equipped with a nose wheel taxi light. The pilot indicated that the absence of this light made it difficult to determine the airplane's position during taxi. The crew of N79771 made no radio calls to ground control about their confusion.