Well, he *almost* made it.
The distance from the NAF in Port Harcourt to Lagos is, what, 250 miles? A clean and light, high-skid 206B should be capable of about 105 KIAS at 80% torque. That's 2.4 hours, give or take.. With 91 gallons onboard and 26 gph, he *should* have had an endurance of 3.5 hours with full tanks. But did they get the thing 100% full? And remember, they dicked around, running it and test-flying it for a total of .5 the day before, so that brought his endurance down to 3.0. Still, that *should* have theoretically given him a 30-minute reserve.
With no en route refueling available, he probably thought/prayed that he could make 100 knots groundspeed, which would give him 2.5 en route. But apparently the flight took 3.0. Did they not go in an absolutely straight line? Were the winds higher than predicted/planned? Can we imagine the thoughts going through that pilot's mind as he looked at the GPS and saw a GS of only 80 knots? Holy cow, what an awful, depressing feeling that must have been! But instead of turning back at the point-of-no-return, he pressed on, maybe hoping the winds would die down and he could get the groundspeed up. Tragically, that never happened.
Once we take off, pilots are eternal optimists. And that pilot's optimism caused him to run his little 206B right out of fuel. With the prospect of a long flight like that...another pilot might have stuck a couple of 5-gallon jugs of Jet-A in the baggage compartment and set down along the way to put them in. Or...the smarter thing to do would've been to top the tank off again before departure.