P2V DR “Navigation in the Old Days” by John Dill
A good reminder of how things used to be. My handheld GPS unit gives me my exact position anywhere on the face of the earth, as well as a host of other valuable information and is a marvel of modern technology. It wasn't always so. I was a crewman on a Navy land based long range patrol plane (P2V Neptune) back in the early 1960's and I'll tell you all what it was like. Quit reading now if you have no interest in this or it will be quite boring (and long).
All of my flying was done in the Pacific between the West Coast of the US and the Far East. We hit just about every island in between including Hawaii, our home port, Midway, Wake, Guam, The Philippines, Japan, Taipei, Okinawa, Viet Nam, the Aleutians, and many other smaller islands which are just dots on a chart.
The Lockheed P2V was a twin engined (actually it had two small jet engines (J34's) added in later models to increase takeoff performance) mid-wing aircraft with a crew of 10. Two pilots, navigator, tactical coordinator, flight engineer, radio operator (me), radar operator, two sensor operators, and an observer/mad operator. Neptunes were unpressurized so we normally stayed below 10,000' to avoid wearing oxygen masks. Our absolute service ceiling was about 30,000'. Long range cruise speed was 170-180 kts. (about 190mph) so a trip from San Francisco to Hawaii was 10 to 12 hours depending on winds aloft. I made that crossing 7 times.
All crewman wore flight suits, survival vests, mae wests, parachute harnesses, leather flying jackets and headsets plugged into the intercom system. In arctic climes we had to wear waterproof rubber POOPY suits with watertight hand, leg and neck cuffs. Those were like being enclosed in a plastic baggy and we would lose a few pounds from perspiration after a long flight.
Our old P2's were noisy, drafty, and smelled of oil, gasoline fumes (on long flights we carried two reinforced rubber gasoline tanks hung in the bomb bay, and they leaked like hell), exhaust fumes, electrics, etc.
The front and rear of the plane were separated by the main wing beam with a tunnel provided for passage. My position in the radio compartment was just aft of the wing beam.
I have many memories of exciting and terrifying times on the P2 but will save those for later. What I wanted to talk about now is how we navigated across the vast Pacific in those primitive days. Our primary nav method was "Dead Reckoning" (emphasis on "dead"). During preflight briefing we would gather what little weather info was available in those days before satellites. The weather folks would give us their best guesstimates of the winds based on reports from ships at sea and other aircraft and we would plot an initial heading.
After launching (Navy lingo for takeoff) we'd fly that heading and plot an assumed course and use any land based navaids that were still in range for a cross check. About 150 miles out to sea we would lose the land based signal and would then rely on the navigator's "How-Goes-It”, a running log of our position, fuel burn, ETA and "point of no return" ("forget it guys, we ain't got enough gas to make it back").
One of the primitive tools we used was called a driftsight. It was sort of a inverted periscope extending from the belly of the aircraft. Laying flat on the deck, one could look through the driftsight at the waves below, assuming we were below the clouds, and lining up two parallel cross hairs with the movement of the waves, could measure our crab angle, or the difference between the aircraft heading and it's actual track. Knowing our true airspeed, we could then compute the winds using simple geometry. At night or in clouds that was impossible of course and most of our flights seemed to be at night.
We also used LORAN. Loran stations, manned by the Coast Guard, were scattered all over the Pacific and were the first real high tech tool available to us back then. I'll do my best to explain how LORAN works, briefly. Suppose you're standing on the beach at Waikiki with a LORAN receiver. Two stations, one on Guam, the other at San Diego, transmit a signal towards you at the exact same instant. The signal from San Diego will arrive first, followed milliseconds later by the signal from Guam. The LORAN receiver computes a line of position for you, meaning you are somewhere on that line. Now, you do the same thing with two other stations and get another line of position. If the LORAN operator is careful and the atmospheric conditions are acceptable, the two lines of position should intersect on the beach at Waikiki, or within a few miles.
The trouble with LORAN was that the signals were in the HF band and very susceptible to interference from electrical storms and static. Often, when we needed it most the signals were unreadable.
When we were in clear weather or above the clouds, hardly ever it seemed, we used my favorite, the sextant. I bugged the navigator to teach me celestial navigation and after a while he would let me take the star shots. I stood on a stool near the nav station and looking through the eyepiece and would try to keep the chosen star in the middle of two crosshairs and a bubble which were both jumping all over. The "bubble sextant" was devised for unstable aircraft and included an averager to even out the wiggles. You tried to keep the star, crosshairs, and bubble centered for 15-30 seconds, some mean feat in turbulence. A sextant measures the inclination of a star, or it's angle above the horizon. The bubble represented our horizon, like a level. Now, if you shot the right star, you had it's angle above the horizon and noting the exact time of the sighting, you'd look in the almanac for a line of position. Quickly then, you'd pick another star about 90 degrees from the first and shoot it the same way, now having two lines of position that like LORAN should intersect at your "fix". We'd tune in to a continuous radio broadcast from the Naval Observatory to get a "time tick" as watches in those days were not accurate enough. Big errors were common due to things like shooting the wrong star (on a coal black night over the Pacific there are millions and millions of them), sloppy aiming, or reading the incorrect angle, or data in the Almanac. But if you were careful, you'd come close and it was really satisfying to now feel like you knew where you were.
Just a note here to say I'm impressed to this day with the professionalism and competence of those guys I flew with. We all were masters of our craft and depended on each other with our lives. Our aircrew was a tight knit unit and every man strived to do his best. On many an occasion that got us through a bad situation without a scratch.
Often, we'd be flying in terrible weather for hours, unable to get either a Loran fix or a star shot. We'd then truly rely on "dead reckoning" using just our magnetic heading and airspeed to compute a position. If fuel was ample, we'd sometimes attempt to climb above the clouds for a star shot, but not knowing the cloud tops, we often could not risk burning the extra gas to climb.
On one occasion, flying from Midway Island to Japan, (about 2400 miles), we were totally lost, not having been able to get a fix for hours. The P2v's max range is just a little bit more than 2400 miles and we all figured we'd have to ditch if we were off course by very much. If you look on a globe you'll see that there is no place to divert along that route, just vast empty ocean. The navigator kept giving the pilot headings to fly, using God only knows what instinct, and after what seemed like an eternity we were able to tune in a radio station in Yokohama and get a bearing. Turns out we were less than 50 miles off course and were able to get to Iwakuni Naval Air Station with gas still in the tanks. Nice job Harry, where ever you are!!
Modern navigation to me is amazing! I look at my small GPS unit and am awestruck by it's capabilities and think back to those days when we had hardly a clue. It was teamwork and perseverance we relied on then. Well, I could go on but I've bored you long enough! Enjoy your next flight in a Boeing 747 across the ocean, but think for a moment of the way it was.
Crew 11 1964-66