Total Solar Eclipse of 1999 August 11
from Air France Concorde F-BVFC flight AF4500
Twenty-six years after the first Hall-of-Fame Concorde 001 record flight during the 1973 June 30 total solar eclipse, three other commercial Concorde were in the umbral path of this new eclipse. The first one, registered as F-BVFC, from Air France (AF4500) and piloted by Captain Jean Prunin†2015 was affreted by the French Astronomy Association and two by British Airways (BA9091C G-BOAC, a.k.a. BA91N with Captain Roger Mills and BA9099C G-BOAA, a.k.a. BA99S with Mike Bannister as Captain). Concorde was the only civilian plane able to "chase" the eclipse because of its speed superior to Mach 2 and because the speed of the umbra was about Mach 2.3 over Europe. Thus the three Concorde managed to stay inside the umbral shadow cone during less than four minutes (for BA9091C and BA9099C) to more than five minutes (for AF4500). However, only the Air France Concorde passengers had the opportunity to view this eclipse from the cabin with an horizontal line-of-sight angle barely under 50 degrees during totality which didn’t facilitate the observations; the two British Airways Concorde passengers had an even worse horizontal line-of-sight angle at more than 60 degrees which made observations even more difficult through the tiny cabin windows and a totality duration under four minutes! Prof John Beckman, an astronomer at the Canary Astrophysical Institute in Tenerife and additionally participant to the historic Concorde 001 ‘73 eclipse flight, was one of the lucky ones, and even he wasn’t totally satisfied. He said: "Because of the small windows and the angle, you could never get your eye in the right position to see totality while the plane was in level flight. It was only when it did a few wiggles in the air that you could see totality. Luckily, I happened to be at the window on one of those occasions, so I saw about 10 seconds of totality. It was obviously disappointing and I’d hoped to see several minutes." Another BA91N passenger reports: "We all struggle to see anything, getting onto the floor and into strange contortions. The pilot had to bank the plane to allow a glimpse of totality - and we saw the solar corona for about half a minute!" The photographies were taken from the Concorde cockpit on Air France flight AF4500. The simulation below, made with my Solar Eclipse Maestro software, refutes the claim that the passengers had over 8 minutes of totality as it was said in the documentary and advertized in most media. The same applies to the two British Airways flights that were operated by Goodwood Travel. After the crash of the Concorde on 2000 July 25th, those three flights were the last to intercept the umbral shadow cone and the 1973 record with its mighty 73 minutes won’t be broken anytime soon, the 2001 June 21st flight having been cancelled.
Concorde flight AF4500 path computations
(last turn before the totality run)
Concorde cockpit crew
(left: Eric Célérier; right: Jean Prunin†2015)
Concorde front flight panel
Earth view from 57,000 feet (17,374 meters)
Flying towards the eclipse
Umbra on the right
Earth from above
Back to Earth ;-)
Postcard of AF4500 Concorde F-BVFC 1999 August 11 Total Solar Eclipse Flight
Certificate of AF4500 Concorde F-BVFC 1999 August 11 Total Solar Eclipse Flight
(the duration of totality was only 5 minutes and 10 seconds contrary to the indicated duration mentioned on the certificate, please read the explanations below)
Lets first study the flight plans of the three Concorde where the arrows indicate the direction of their trajectories. During the eclipse intercept the G-BOAC and G-BOAA Concorde were flying at an altitude of 51,000 feet (15,545 meters) and 54,000 feet (16,459 meters) respectively while F-BVFC flew at 57,000 feet (17,374 meters) under an exterior temperature of about -60°C (-76F). Their cruising speed was around Mach 2 which is about 2,150 kph or 1,340 mph. The areas where the supersonics were inside the umbral shadow cone, and as such experienced totality, are materialized by the two light blue digits 1 and 2 respectively for the two British Concorde and the French one. As one can see the area of interception for the two British Concorde is much further west than the French one, and this by itself will have the consequence of seriously reducing their totality duration the umbra velocity in this area being substantially higher as explained later. One additional consequence is an extremely miserable horizontal line-of-sight angle through the tiny and narrow windows of the Concorde passenger cabin, absolutely not what you’re looking for as a passenger!
Flight plans of the three Concorde (the arrows indicate the direction of their trajectories)
And now lets have a look at the umbral shadow speed as it races from one end to the other along the eclipse path. It’s easy to notice that during the Concorde intercepts this velocity was above 3,500 kilometers per hour for the French Concorde (red arrow) and 4,400 kilometers per hour for the two British Concorde (dark blue arrow), which leads to speed differentials of 1,350 kilometers per hour and 2,250 kilometers per hour respectively compared to the Concorde cruising speed of 2,150 kilometers per hour. It’s immediately apparent that the speeches of the Captains are highly problematic and misleading because they all use the lowest umbral shadow velocity, which is slightly above 2,400 kilometers per hour for this eclipse, when in fact this velocity occurs only a good hour after their intercept, moreover over Europe where flying supersonic wasn’t possible! New quack… which considerably reduces the observable totality duration to well under six minutes and even under four minutes for the two British Concorde.
Umbral shadow cone velocity during the eclipse across the globe
Umbral shadow cone velocity during the Concorde intercepts
We can now move on to the horizontal line-of-sight angle through the tiny windows of the Concorde. Because of the totality run trajectory of the French Concorde this angle was slightly under 50 degrees during totality which is already not good at all; yet the passengers of the two British Concorde had an even worse experience with an angle of about 60 degrees making it next to impossible to see anything! This is completely unacceptable. On the simulation below the shaded ribbon is the totality path at sea level, while the dotted lines delimit the path at an altitude of 57,000 feet (17,374 meters). The shaded ellipse is the umbra at a given time, the aircraft must move inside to witness a totality. The yellow arrow indicates the direction of the eclipsed Sun and as such shows the horizontal line-of-sight angle from the Concorde’s cabine windows.
In this short documentary Jean Prunin†2015, the Concorde’s captain, who prepared the eclipse flight plan claims they had 8 minutes and 10 seconds of totality. However, to be accurate, they only had slightly over 5 minutes and 10 seconds of totality as the above simulation clearly shows. What lasted 8 minutes and 10 seconds is the whole run on the map below that includes some of the partial phases (in dark blue) before and after totality (in red). The flight plan, which can be seen on two pictures above and on the figure below, was to start the interception trajectory at N4950.0 and W01300.0, end it at N5020.0 and W00900.0 (complete flight plan in Google Earth, description in French of the computations done by Jean Prunin which explain the small mistakes and approximations made).
A later intercept combined with a flight parallel to the umbra would have allowed a totality duration of nearly 6 minutes, and even more if flying at Mach 2 over Cape Lizard had been authorized.
Rencontre avec une ombre - Encounter with a shadow (duration: 5 minutes 36 seconds)
[requires an H.264/MPEG-4 decoder: Windows users can install the Windows Essentials Codec Pack]
And now what about the two British Concorde? Here is a detailed map of the flight routes devised by Lucy Pesaro from British Airways. One quickly realizes that it was decided to fly with the umbral shadow despite an extremely unfavorable horizontal (azimuthal) line-of-sight angle with more than 60 degrees!
It is perfectly clear that British Airways flights have not reached the eight minutes of totality (in fact far from it with less than four minutes as can be seen on the simulation below) promised by the tour operator Goodwood Travel, which anyway was physically impossible. Sadly these flights were badly planned and by people who do not have sufficient knowledge of the subject. If you want to plan any such eclipse flight please contact me as my expertise will prove to be extremely useful for a successsful flight and eclipse observation.
Having a look at papers written in the media is also revealing. For example this one in Libération: a teasing title but for the privileged viewsite you could pass your turn! Hey, how strange it is, we are now only talking about 7 minutes of totality!? And all this despite the sponsorship of the French Association for Astronomy (AFA). The Concorde will indeed be caught by the umbral shadow around 12:02 but why then provide 2,850 kph as the speed of the umbra, which is actually the one near Paris, while the Concorde is off the coast of Ireland where the speed is actually above 3,600 kph… and this is not a minor detail or an oversight. All this only confirms the lack of knowledge from the various parties involved in this project, the deceleration of the umbral shadow being consistent before its arrival on the European seashores. The result of all this is that the end of totality came far earlier and the "gentle turn on the left to go back slightly to the north" couldn’t help in any way. The other papers are of the same kind which shows that the communication was orchestrated and based on erroneous data. In short a PR stunt but with a very questionable result and which could be described as deception, some "fake news" in the old way somehow.
Paper published in Libération on 10 August 1999
Another eclipse flight at only 25,000 feet (7,620 meters), using a pressurized turboprop Twin Commander airplane cruising at 278 knots, took off from Bedford in Massachusetts to intercept the shadow cone shortly after sunrise. The documentary, from Peter Ceravolo, tells the story of how Mitch Sayare, Dennis di Cicco and Peter Ceravolo planned and executed the flight to intercept the path of totality 300 miles off the coast of New England, south of Nova Scotia. They had a short totality duration, about fifty seconds, yet with an enticing and fruitful observation from the cockpit. IMO a great success and well worth experience.