Jean-Charles Duboc, pilot, indicates in the "dimension" field:
The date of filling of the form is undoubtedly after 1997. The form is said to be a part of a "Synthesis of the report of investigation for the SEPRA" by Dominique Weinstein and Patrick Leprevost for the SEPRA, dated "2001 Weinstein/SEPRA".
Valérie Chauffour, co-pilot, indicates in the "dimension" field:
No angular size is indicated.
The date of filling of the form is undoubtedly after 1997. The form is said to be a part of a "Synthesis of the report of investigation for the SEPRA" by Dominique Weinstein and Patrick Leprevost for the SEPRA, dated "2001 Weinstein/SEPRA".
The author indicates:
No angular size is indicated.
No angular size is indicated.
The author indicates that he publishes what Jean-Charles Duboc told.
It is indicated there that first the stewart saw an object in the sky and exclaimed "a weather balloon!", then the copilot also identified it as a weather balloon, then Jean-Charles Duboc indicates that having seen it the last, he rather thought of a plane banking of 45 degrees of slope before it has its wings horizontal, then thought that it was a rather strange object.
Jean-Charles Duboc then states that the excellent conditions of visibility and the presence of altocumulus clouds enabled him to estimate that the object was at 46 kilometers below [sic] the plane, at an altitude of 10.500 meters and in the direction 10 hours in the North-West practically at the vertical of Paris.
Jean-Charles Duboc then describes the object as having taken the shape of a bell with slightly vague contour which changed to a sort of brownish lens.
It is indicated that he managed to estimate its gigantic dimensions as being of 1000 meters in diameter [width] for 100 meters thickness [height] whereas an airliner at this distance would have been only a tiny dot. The object had neither wings neither control surface nor engine and could be seen under several angles during nearly one minute.
It is indicated that when it was passed on the left of the plane it was seen by the crew becoming suddenly transparent and disappearing without moving.
No angular size is indicated.
An insert in this magazine indicates that the observed phenomenon had "several tens of meters", affirming that the estimate of this size was made by the SEPRA according to radar data.
No angular size is indicated.
The article indicates that the steward and the copilot immediately identifed the object as being a weather balloon and only the pilot sees in it a weird object but without sufficient certainty to submit an official UFO report on his own.
No angular size is indicated.
The report indicates that the stewart present in the cockpit announces a phenomenon which appears to him to be a weather balloon, his observation is confirmed by the copilot, the pilot who sees it in his turn thinks that it is a plane in a 45 degrees slope. Very quickly, the three agree to note that what they see does not resemble anything. Because of its apparent diameter, they deduce that the object is of big size. The apparatus had changes in form, initially a brown bell, then a chestnut brown lens, then a quasi instantaneous disappearance on the left of the plane.
The report indicates that an investigation by the CODA (Center of the Operations of Air Defense) of Taverny brought back to 250 meters the size of the observed apparatus by being basing themselves upon the precise distance of the crossing of the trajectories of the plane and the phenomenon.
No angular size is indicated.
And:
No angular size is indicated.
Jean-Charles Duboc indicates:
No angular size is indicated.
[Recording not found yet.]
Jean-Charles Duboc indicates:
No angular size is indicated.
Jean-Charles Duboc indicates:
No angular size is indicated.
The authors indicate that the stewart chief of cabin announces an object on the left of the Airbus. "a weather balloon?" Jean-Charles Duboc thinks that it is rather a plane "in turn with 45 degrees banking", the copilot moved for better seeing and is on the left behind Duboc's seat and finally all the three agree to say that the phenomenon resembles nothing known. The shape of the object seems to be changing. It is at an approximate distance of fifty kilometers at the altitude of ten thousand five hundred meters, according to a layer of altocumulus to the background being used as reference mark. "Taking into account its apparent diameter there is no doubt that it is of big size..." According to Jean Charles Duboc it has initially the shape of a flattened bell which transforms into a dark red disc without control surface nor engine. The authors quote:
The authors indicate that it finally took the aspect of a lens before disappearing suddenly.
The authors indicate that the copilot says that it was a dark brown disc which changed form all the time by alternating clear and fuzzy contours, and which volatilized.
The authors quote the copilot as saying:
And:
The authors indicate that the pilots made drawings that show a slight difference in perception and which "essentials" remains the same however, indicated as like a kind of giant disc, of red color, which will change form. The authors indicate that the two pilots agree on the suddenness of disappearance.
The authors note that the crew had initially estimated that the object had one kilometers in length, size which was brought back to initially three hundred meters, then five hundred meters during the reconstitution by comparison in angular dimension, "(small finger held at arm's length)."
Jean Charles Duboc is the guest and says:
Upon questioning "what did it look like approximately Mr. Duboc?":
Upon questioning "so it had a discoid shape, then?"
Upon questioning "bigger or smaller than your plane?"
Upon questioning "so it could have contained straightforwardly your own plane inside it?"
On comment "that's huge.":
No angular size is indicated.
Jean-Charles Duboc indicates:
No angular size is indicated.
Jean-Charles Duboc indicates:
Upon questioning "and you were the only one to see it?"
Upon questioning "what's the reaction when you see that?"
Upon questioning "progressively?":
Jean-Jacques Vélasco then states that there was two minutes of visual observation on behalf of the crew, that a military or civilian plane at a distance of 40 kilometers appears the size of a point of ball point pen held at arm's length.
Jean-Jacques Vélasco indicates that it was requested separately from the pilot and to the copilot to what would the "dimension at arm's length" corresponds, he states:
After reaction in [ta20], Eric Maillot corrects, 1/2 of the moon, i.e. 0.25°, are not 0.15 arc minutes but 15 arc minutes.
On March 24 2007, Jean-Charles Duboc published a comment on the website of the association "L'Observatoire Zététique," indicating:
The URL indicated by Jean-Charles Duboc point to an unsigned web page giving again elements of [ta7].
In addition, the page's author indicates:
LL alerts on an error on the source [ta17]:
1/2 of the moon, i.e. 0.25°, are not 0.15 arc minutes as indicated in [ta17], but 15 arc minutes.
The page, about the size of the phenomenon, indicates that "the crew of the Air France flight observes a large brown - red disc of changing form and which seems of very big size."
No angular size is indicated.
| Ref.: | Type of source: | J.-C. Duboc: | V. Chauffour: | J.-J. Vélasco: | Others: |
|---|---|---|---|---|---|
| ta1 | Form. | 1/2 of the diameter of the moon. | N/A. | N/A. | N/A. |
| ta2 | Form. | N/A. | Nothing. | N/A. | N/A. |
| ta3 | Paris-Match magazine. | Nothing. | Nothing. | N/A. | Nothing. |
| ta4 | Article in the scientific journal JSE. | Nothing. | Nothing. | Nothing. | Nothing. |
| ta5 | VSD OVNIS Magazine. | Nothing. | Nothing. | N/A. | Nothing. |
| ta19 | Facteur X ufology magazine. | Nothing. | Nothing. | N/A. | N/A. |
| ta6 | Web page by Eric Maillot. | N/A. | N/A. | N/A. | Nothing. |
| ta7 | COMETA report. | Nothing. | Nothing. | N/A. | Nothing. |
| ta8 | Witness interview by ufologist. | Nothing. | N/A. | N/A. | N/A. |
| ta9 | Witness interview on TV. | Nothing. | N/A. | N/A. | N/A. |
| ta10 | Witness interview on TV. | N/A. | N/A. | N/A. | N/A. |
| ta11 | Witness interview on TV. | Nothing. | N/A. | N/A. | N/A. |
| ta12 | Witness interview on TV documentary. | Nothing. | N/A. | N/A. | N/A. |
| ta13 | Book by investigator JJV. | Uncertain, small finger at arm's length. | Uncertain, small finger at arm's length. | Small finger at arm's length. | Uncertain, small finger at arm's length. |
| ta14 | Witness interview, ufology radio show. | Nothing. | N/A. | N/A. | N/A. |
| ta15 | Witness interview, ufology radio show. | Nothing. | N/A. | N/A. | N/A. |
| ta16 | TV show. | Nothing. | N/A. | The thumb at arm's length. | N/A. |
| ta17 | Eric Maillot. | N/A. | N/A. | N/A. | 1/2 of the moon. |
| ta18 | Web page indicated by witness. | 6mm, a quarter of the thumb at arm's length." | N/A | N/A | N/A |
| ta21 | GEIPAN web page. | Nothing. | Nothing. | N/A. | Nothing. |
| Id: | Topic: | Severity: | Date noted: | Raised by: | Noted by: | Description: | Proposal: | Status: |
|---|---|---|---|---|---|---|---|---|
| 1 | Data | Severe | May 5, 2007 | Patrick Gross | Patrick Gross | No investigation report available. | Help needed. | Open. |
| 2 | Ufology | Severe | May 5, 2007 | Patrick Gross | Patrick Gross | Among 3 witnesses, only 1 provides an angular size. | Help needed. | Open. |
| 3 | Ufology | Severe | May 5, 2007 | Patrick Gross | Patrick Gross | No information on method of estimate of angular size. | Help needed. | Open. |
Mr. Jean-Charles Duboc indicated an angular size twice: the first time by filling an official ufology sighting report form, indicating a size equivalent to that of half of the apparent size of the moon [ta1], the second time by quoting a web page about the sighting as indicating an angular size corresponding to the apparent size of a quarter of the thickness of the thumb at arm's length, approximately 6 millimetres [ta18], which is consistent with his first indication. I did not find any contradictory statement of the witness on this matter.
No angular size was indicated directly by the two other witnesses, in the sources that are available to me, which is very unfortunate. A case with multiple witness is not really a multiple witness case if only one witness provides information.
To get witnesses to fill a "Dimension:" field on a form is in no way a valid method. Here, only Jean-Charles Duboc realized that an angular size was the only information that makes sense, the copilot providing as answer "very big", which is quantitatively meaningless.
Mr. Jean-Jacques Vélasco, at the time of the SEPRA within the CNES, indicated in his 2004 book an angular size corresponding to the apparent size of a small finger at arm's length, i.e. approximately 18 millimeters. In a general public TV show in 2007, in the presence of the witness Jean-Charles Duboc, he indicates in an angular size corresponding to the apparent size of a thumb at arm's length, i.e. approximately 25 mm.
This is a rather odd situation, in which the angular size given initially by the witness had been tripled, then quadrupled.
The manner in which the size angular was measured, or estimated, is indicated nowhere by anybody. A request that I made on this matter did not receive an effective answer.
At the best of what can be deduced on the matter, it seems that the angular size of the UFO was about that of half of full moon, that is to say about 15 arc minutes.
If the UFO were indeed at a 46 kilometers distance, it corresponds to a real width of 200,70 meters. This is a figure which appears in several sources, but itself prone to variations from one source to another.
The following table gives various examples of an approximate real dimension of a 15 arc minute at various distances:
| For a distance of: | The object's width would be at: |
|---|---|
| 100 meters | 45 centimeters |
| 1 kilometer | 4.30 meters |
| 5 kilomètre | 21 meters |
| 10 kilometers | 43 meters |
| 15 kilometers | 65 meters |
| 20 kilometers | 87 meters |
| 30 kilometers | 130 meters |
| 40 kilometers | 175 meters |
| 46 kilometers | 200 meters |
| 50 kilometers | 218 meters |
| 80 kilometers | 350 meters |
| 100 kilometers | 436 meters |
| Version: | Created/changed by: | Date: | Change description: |
|---|---|---|---|
| 0.1 Draft | Patrick Gross | March 27, 2007 | Creation: [ta1] to [ta9] and [ta11] to [ta17] |
| 0.1 Draft | Patrick Gross | March 27, 2007 | Communicated to the members of the Internet discussion list "L'Observatoire Zététique" for comments, corrections, possible additional information. |
| 0.2b Draft | Patrick Gross | March 28, 2007 | Addition for [ta1] and [ta2] of the paragraph: "The date of filling of the form is undoubtedly after 1997. The form is said to be a part of a "Synthesis of the report of investigation for the SEPRA" by Dominique Weinstein and Patrick Leprevost for the SEPRA, dated '2001 Weinstein/SEPRA'." Addition of [ta18]. Addition of [ta19] as unavailable source. All these additions were made following information by Eric Maillot after the day before communication to the members of the discussion list "L'Observatoire Zététique". |
| 0.2c Draft | Patrick Gross | March 28, 2007 | Addition de [ta20]. |
| 0.2d Draft | Patrick Gross | April 1, 2007 | Addition of content for [ta19]. |
| 0.2e Draft | Patrick Gross | April 29, 2007 | Addition of the original version in English for [ta4], and addition of [ta21]. |
| 0.2f Draft | Patrick Gross | May 6, 2007 | Addition of the Summary Table, the List of Issue and the Synthesis. Creation of the English version of the document. |
| 0.3 Productive | Patrick Gross | May 6, 2007 | First announced publication on the author's website www.ufologie.net in the "site updates" section and publication URL defined. Information thereof sent to the discussion list "L'Observatoire Zététique" for possible late comments. |
| 1.0 Productive | Patrick Gross | June 21, 2007 | Conversion from HTML4 to XHTML strict. |