If you fly or if you have ever flown a small aircraft, you have flown to the aircraft's maximum range at least once, some of us multiple times. As an enthusiastic young pilot in a USMC scout aircraft, a Cessna 0-1, the range was variable depending on all of the weather conditions. If hot, you burned a lot of fuel on takeoff limiting your mission time. If reasonably cool and you were not changing altitude constantly, you could really extend your range.
This incident was sometime during 1964 when the silly "war" was not yet in full bloom. The Marines flew sorties constantly in support of the South Vietnamese ground troops and artillery. We were also charged with spotting for a few sorties by either the U.S. Air Force or the Navy. A heavy troop concentration received a few canisters of smoke as a calling card and some very slow but extremely accurate P-51 Mustangs would lay in their devastating load.
Sometimes we were just fishing. Other times we were sent to mark the exact spot. We had an extremely modern method of dropping smoke from some under wing canisters that were supposed to release when you pulled the release. They usually didn't release. The alternative always worked: Push open window, pull pin, drop canister. No big deal right? You had to do this at around a thousand feet to put the smoke on target. Ground fire reaches around five thousand feet with penetrating force so it was possible to get some extra holes in your aircraft.
You can spot ground activity easily at five, six, and even seven thousand feet. But to mark the spot, you almost have to be down about a thousand feet. That means you cranked up to the max speed of about 125-130 knots and buzzed the spot hoping the enemy ground troops forget to lead the target. So if you were busy, you would burn fuel faster.
The Military plays everything safe. The aircraft had about a four and a half hour maximum range but we could only file for two and half hours with a half hour reserve. I doubt many sorties were less than three hours and fifteen minutes to three and a half hours. They only checked your time out and didn't really check on when you got back. Just that you came back.
Landing became a problem at Danang in the last half of 1964 because our forces couldn't keep the glide path clear of snipers. If you were on an even short final, you passed over an area that was full of men who had learned how to shoot at aircraft. Shooting at a bird doing about sixty to seventy knots was easy.
One day I had pushed my limit a little and was coming back after nearly four hours of looking for activity. I kept thinking I saw something and circled to see if I could see more movement. It took a lot of time. I should have just gone on to the next quadrant instead of double and triple checking but I didn't. This made me run a little late getting home.
I radioed to advise I was going to come in crosswind and turn down for a short glide slope as I didn't want to have to glide over the sharpshooters. They had been putting holes in the wings of aircraft all week. That meant new fuel bladders and always the possibility of a fire or a lucky hit on the pilot.