Twilight flight

A very special flight!

It was the end of the day in a squadron in Dijon. The day’s flights had landed, the pilots on the last lap debriefing, the mechanics were busy getting the planes ready for the next day. I had flown in the morning…a simple flight, for the benefit of a young pilot who was attacking his “transformer” on our brand new Mirage 2000-5…magnificent and accomplished version of the Mirage 2000 Air Defense series.
Suddenly, the squadron’s sound system crackles… I’m called to ops.
– Can you go to Mont-de-Marsan?
– Yeah…when?
– Immediately…we must bring 2 planes to the CEAM (Military Air Experimentation Center) before nightfall. They need planes to validate a new restitution system tomorrow morning but they have too many broken down planes and the validation will only be done if they have enough participants! You are going with XX (a young pilot). Be careful, you will not be able to land there after the aero night (30 minutes after sunset)…
– OK ! but the sun is setting soon!
– If you arrive too late, you land in Cazaux and take off from there to do the mission tomorrow morning.
I immediately thought that we had to hurry. A big mission at the CEAM, I preferred to do it starting from the same terrain as the other planes in the patrol. This kind of mission was very often carried out by very experienced pilots, very oriented towards the technical mission of experimentation and unaccustomed to the emotions of a young crew member whose main concern was to know how to reassemble the patrol, stay in place and return arise. I therefore preferred to participate in the mass brief (briefing with all the speakers) and then give additional instructions to my number 2.
– Well, the weather is perfect all over France… We’re off… no time to ask us a flight plan at High Altitude… can you ask us a flight plan in COM Victor while we’re going to the planes? Direct route to Marsan!
– OK !
Ultra fast briefing, we collect our planes by signing the FORM 11. The planes are ready.
We set off when the sun was almost down…it was getting dark! We are quickly cleared to taxi and take off and immediately head west-southwest.
We move away from the ground by climbing slightly in order to overcome the maximum speeds at very low altitude (the speed is limited to 450 Kts under 1500 feet above the ground) and we accelerate to Mach 0.95. It is now dark and the sun has disappeared over the horizon.
I prepare the system for an arrival in Mont-de-Marsan, contact the Saint-Yan airfield whose area we are crossing, take a look at my map to check the future areas that we will cross while always looking outside, the rule in visual flight being to see and avoid other planes…even if at this hour, other planes are rare! I am also embarrassed … the low sun dazzles me a little.
The low sun?…it seemed to me, however, that it had set!
I try to observe the sun, lower the smoked visor of my helmet so as not to be too dazzled…and I note that the sun is indeed rising in the west! I can not believe it ! Only one possibility: we are going faster than the rotation of the earth! However, I underwent a solid aero training, more than 2000 hours of flight in Mirage and I had never thought of this phenomenon…
Quick calculation: The complete circumference of the planet is 360 degrees, each measuring 60 nautical miles at the equator. we are at about 45° north latitude, that is 60 X 0.7 (the cosine of 45°) = 42 nautical miles = the length of one degree at our latitudes. 42 x 360 = good a little over 15,000 nautical miles…which represents the circumference of the planet under 45°. And 15,000 / 24 hours = approximately 625 nautical miles per hour…so we need to go faster than 625 Kts…and that is precisely the indicated airspeed at which we are flying at 4000 feet, a slightly higher ground speed…confirmed in glancing at the inertial unit.
To achieve this very special moment, it took the conjunction of several elements:
Fly with a westerly heading, just after sunset and fast enough to “catch up” with the sun. This speed could only be reached at low altitude without going into supersonic flight…which is prohibited above national territory.
I took a few seconds to savor this rare moment which has remained precious to me. A few seconds because obviously at these speeds, you can’t yawn at the crows for very long!
We reduced our speed as we approached Mont-de-Marsan, which very quickly caused another sunset! However, we landed at our destination before the fateful half-hour which would have diverted us to Cazaux…
Memories of Mirage flights…I have plenty of them! First solo, first take-off on alert, fierce close combat, in-flight refueling in capricious weather, breakdown return, first war mission, qualification flights, etc. The fact remains that these few minutes spent contemplating a sunrise sun in the west in the tranquility of an end-of-day flight will remain as one of the moments when I really had the feeling of being privileged!