CORROBORATED
CF-GEI-20180450518 CORROBORATED
The Tourdun Long-Exposure Aircraft Case
CASE FILE — CF-GEI-20180450518 — CASEFILES CLASSIFIED ARCHIVE
Date Date when the incident was reported or occurred
2018-04-17
Location Reported location of the sighting or event
Tourdun, Gers, France
Duration Estimated duration of the observed phenomenon
2 seconds
Object Type Classification of the observed object based on witness descriptions
light
Source Origin database or archive this case was sourced from
geipan
Witnesses Number of known witnesses who reported the event
1
Country Country where the incident took place
FR
AI Confidence AI-generated credibility score based on source reliability, detail consistency, and corroboration
85%
On April 17, 2018, at 21:00 hours in Tourdun (Gers department, France), a single witness was conducting long-exposure astrophotography aimed at the zenith between the constellations Ursa Major and Leo when he captured what he initially believed to be an ordinary aircraft contrail. Simultaneously during the two-second exposure, he noticed intermittent illumination of the ground within his peripheral visual field. The witness submitted the photographic evidence to GEIPAN (France's official UAP investigation body under CNES).
GEIPAN investigators employed stellar calibration software to analyze the photograph, successfully identifying the star field captured in the image. By cross-referencing the aircraft trajectory with real-time flight data, investigators positively identified the object as Lufthansa flight LH1792/DLH05A, an Airbus A321 operating the regular Munich-Lisbon route. The investigation revealed an anomaly in the aircraft's anti-collision lighting sequence: the wingtip strobe lights flashed four times or randomly rather than the standard twice in rapid succession at one-hertz frequency, indicating a malfunction of the aircraft's lighting system.
The witness's perception of the ground illumination evolved during the investigation. Initially described as occurring "at the same time" as the observation, the witness later clarified to GEIPAN investigators: "my astonishment came when seeing the detail on the photo. It was then that the luminous impression on the ground became conscious to me." This revision proved crucial to understanding the case as an example of psychological priming in anomalous phenomenon reporting.
02 Timeline of Events
21:00
Long-Exposure Photography Begins
Witness begins taking long-exposure photograph of the sky at zenith, aimed between Ursa Major and Leo constellations
21:00 + ~2 seconds
Trail Captured and Ground Illumination Noticed
During the exposure, witness notices what appears to be an aircraft trail and observes intermittent ground illumination in peripheral vision lasting approximately 2 seconds
21:00 + several minutes
Photograph Review
Upon reviewing the captured image, witness notices unusual details in the light trail that increase perception of strangeness and consciously registers the ground illumination memory
Post-incident
Report Submitted to GEIPAN
Witness submits report and photographic evidence to GEIPAN for official investigation
Investigation phase
Stellar Calibration Analysis
GEIPAN investigators use online stellar calibration tools to identify star field in photograph and determine observation azimuth and aircraft trajectory axis
Investigation phase
Flight Data Correlation
Cross-referencing trajectory with flight data positively identifies aircraft as Lufthansa flight LH1792/DLH05A (Airbus A321, Munich-Lisbon route)
Investigation conclusion
Classification A Assigned
GEIPAN classifies case as 'A' (identified with certainty): observation of aircraft with malfunctioning anti-collision lights. Strangeness perceived retrospectively after viewing photograph
03 Key Witnesses
Anonymous Witness 1
Amateur astrophotographer
medium
Individual conducting long-exposure photography of the night sky, familiar enough with aviation to initially identify the trail as likely aircraft-related
"Mon étonnement vint en voyant le détail sur la photo. C'est alors que l'impression lumineuse sur le sol m'est devenu conscient. [My astonishment came when seeing the detail on the photo. It was then that the luminous impression on the ground became conscious to me.]"
04 Analyst Notes -- AI Processed
This case exemplifies the value of rigorous scientific investigation and demonstrates GEIPAN's methodological excellence. The investigators utilized multiple verification layers: stellar field identification, azimuth calculation, trajectory analysis, and flight data correlation. The positive identification of flight LH1792/DLH05A is conclusive. However, the investigation also reveals important psychological factors in witness reporting.
GEIPAN's analysis highlights the 'priming phenomenon' (phénomène d'amorçage) whereby an initial perceived anomaly creates heightened awareness that can lead witnesses to associate unrelated stimuli or amplify normal events into perceived strangeness. The witness's revised testimony—admitting the ground illumination only became consciously significant after reviewing the photograph—supports this interpretation. The investigators reasonably suggest mundane sources for the ground illumination: passing vehicle headlights, a neighbor's flashlight, or similar local light sources. The case suffers from weak consistency: no original photograph was provided (requiring reconstruction), no environmental data about the witness location was collected, and the witness's description evolved between initial report and follow-up questioning. Despite these limitations, the aircraft identification is definitive.
05 Theory Comparison
BELIEVER ANALYSIS
SKEPTIC ANALYSIS
Weakness in Evidence Chain
While the aircraft identification is solid, several factors weaken the overall case consistency: the witness never provided the original photograph (forcing investigators to reconstruct angular data), no environmental survey was conducted to identify possible ground illumination sources, and the witness's description changed between initial and follow-up reports. These gaps, while not preventing the explanation, demonstrate the limitations of investigations where physical evidence is incomplete and witness memory may be influenced by suggestion or retrospective interpretation.
06 Verdict
ANALYST VERDICT
This case is conclusively explained as the observation of Lufthansa flight LH1792/DLH05A, an Airbus A321, with a malfunctioning anti-collision lighting system captured during long-exposure astrophotography. The GEIPAN classification of 'A' (identified with certainty) is entirely appropriate. The significance of this case lies not in any genuine anomaly, but in its demonstration of proper investigative methodology and its illustration of psychological factors in UAP reporting. The witness acted responsibly by reporting the observation, and GEIPAN's thorough analysis—including stellar calibration, flight data correlation, and psychological assessment—represents best practices in anomaly investigation. The malfunctioning aircraft lights, while unusual, fall well within normal aviation maintenance issues. Confidence in this explanation: very high (95%+).
AI CONFIDENCE SCORE:
85%
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