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ALSACAT is my comprehensive catalog of UFO sighting reports in Alsace, the region is the North-East of France, whether they are "explained" or "unexplained".

The ALSACAT catalog is made of case files with a case number, summary, quantitative information (date, location, number of witnesses...), classifications, all sources mentioning the case with their references, a discussion of the case in order to evaluate its causes, and a history of the changes made to the file. A general index and thematic sub-catalogs give access to these Alsatian case files.

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Case of Obernai, on June 7, 2006:

Case number:



Someone unnamed filed his report on the web forum of the SPICA Alsatian ufology association.

The person, near Obernai in the Bas-Rhin, on June 7, 2006, around 03:30 p.m., looked at the sky and saw "very high" in the sky "a kind of airliner, except that there was like two other planes that "accompanied" it, one on each side, and those there were 5 to 6 times smaller than the latter, it felt like a triangle and there were 3 trails of condensation for the 3 objects flying at a relatively slow speed... "

The witness looked down for 2 seconds then again looked at the sky, and there was nothing left at all: the three objects had disappeared and there was not a cloud, and no contrail anymore.


Temporal data:

Date: June 7, 2006
Time: ~03:30 p.m.
Duration: ?
First known report date: August 2006
Reporting delay: Hours.

Geographical data:

Department: Haut-Rhin
City: Obernai
Place: ?
Latitude: 48.459
Longitude: 7.485
Uncertainty radius: 3 km

Witnesses data:

Number of alleged witnesses: 1
Number of known witnesses: 1
Number of named witnesses: 0
Witness(es) ages: ?
Witness(es) types: ?

Ufology data:

Reporting channel: Web report to ufology forum SPICA.
Type of location: ?, UFO in the sky.
Visibility conditions: Day
UFO observed: Yes
UFO arrival observed: ?
UFO departure observed: Yes
Entities: No
Photographs: No.
Sketch(s) by witness(es): No.
Sketch(es) approved by witness(es): No.
Witness(es) feelings: Puzzled.
Witnesses interpretation: ?


Hynek: DD
ALSACAT: Probable planes in in-light refueling.




June 7, 2006, Obernai (67)

Source: SPICA Forum

here it is this afternoon near Obernai, about 3:30 p.m. I looked at the sky, and I saw very very high in the sky a kind of airliner, except that here there was like two other planes that "the accompanied ", one on each side, and those there were 5-6 times smaller than the latter, it felt like a triangle and there were 3 trails of condensation for the 3 objects flying at at a fairly slow speed...

i looked down for a moment and two seconds later I looked at the sky again and nothing at all: the three objects had disappeared and not a cloud, no vapor trail anymore..


City Date and hour of observation General shape
General color
OBERNAI Wednesday 7 June 2006 at 03:30 p.m. regular polygon
information not communicated
Unsolved -lack of info



There is in fact little real strangeness in this report.

The plane im the middle is bigger than those at its sides a little behind, forming a triangle. This corresponds to a refueller plane and two refueling jet fighters.

It is well known that planes can leave contrails. Are they sometimes interrupted? Yes.

One possible scenario is that of an in-flight refueling of jet fighter planes. When refueling, they have to keep a slow pace equal to that of the tanker aircraft. The refueling done, they will logically use a different speed, and change altitude.

In such an operation, special condensation trails may occur, such as those called "wingtips vortex", condensation on the wing tips due to aerodynamic vortices when an airplane is not flying at the speed for which it was aerodynamically optimized, but at an unusually slow pace, such as during in-flight refueling operations.

The image below shows this scenario:


Once the refueling operation is over, the contrails are then interrupted, and the planes cannot be easily spotted anymore in the sky - the witness specifies that they were "very very high", probably unnoticeable when there is no contrail. Also, they might have veered, taking an albedo similar to that of the sky color then.

As I do not have better data, I obviously cannot "scientifically prove" that this is indeed the correct explanation, but I'd like to see what evidence to the contrary would support a better explanation.


Probable planes in in-light refueling.

Sources references:

* = Source is available to me.
? = Source I am told about but could not get so far. Help needed.

File history:


Main author: Patrick Gross
Contributors: None
Reviewers: None
Editor: Patrick Gross

Changes history:

Version: Create/changed by: Date: Description:
0.1 Patrick Gross May 5, 2015 Creation, [spa1].
1.0 Patrick Gross May 5, 2015 First published.
1.1 Patrick Gross June 13, 2015 Addition [spa4].

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This page was last updated on June 13, 2015.