United Airlines personnel reported an unusual round appearance above or near Gate C17 at Chicago O'Hare on 7 November 2006. Some described an apparently stationary object, followed by rapid departure and a cloud opening. Airline staff contacted the Federal Aviation Administration tower, whose personnel reported no visual sighting. Early anonymous submissions and NARCAP's subsequent investigation preserve different viewing positions and reporting roles. The airline employees, ground workers and pilots are overlapping occupational categories; their accounts require individual comparison rather than three separate witness totals. The surviving evidence documents an operational report and several visual descriptions, while the physical source and its alleged effect on the cloud remain unresolved.
Management and supervisory observations, with airline operations personnel who relayed reports; ramp mechanics and flight crew are reviewed separately
United Airlines employees
Supervisory observation and the reporting chain
NUFORC report 53392 describes a management employee hearing a company-radio announcement, leaving an office and seeing a small object apparently hovering over C17. The narrator initially estimated about 1,000 feet altitude and said that it moved rapidly eastward after approximately a minute. The submission then recounts what an employee at the gate said about looking directly upward, rotation and cockpit personnel opening windows. That second passage is a colleague's account within the narrative, rather than another direct observation by its narrator.
The National UFO Reporting Center explicitly says it revised this submission to disguise the contributor and that the result may synthesise information from several people. It also changed the displayed event time from the contributor's estimate. NARCAP's later supervisor account adds a small angular-size comparison and a steep departure, and describes another employee initially dismissing the appearance as a bird. These details reach the public through investigator presentation rather than a complete, named statement set.
The FAA telephone transcription published by NARCAP records Sue in the United ramp tower asking whether the FAA tower had seen a flying disc. She attributes the report to a pilot near C17 and explains that her own position prevents a view directly above. Subsequent calls repeat the report; one says someone obtained a picture. FAA personnel reply that they have seen nothing. These calls establish that the report entered airport communications, while keeping the callers' relayed information separate from direct viewing.
Evidence review
The management submission preserves both personal perception and workplace reporting. Its deliberately disguised and potentially composite form limits reconstruction of one contributor's exact position or sequence. Its displayed observer count is a report field, not a publicly verified roster. Reappearance of the same material in NARCAP's synthesis adds investigation and context without creating additional independent witnesses.
The reproduced FAA facility log records the ramp-tower inquiry at 22:45 UTC, or 4:45 pm Central Standard Time, and quality-assurance closure at 23:03 UTC. NARCAP's first-call transcription gives 4:30 pm. The differing entries document the report's handling but leave the precise relationship between the first call and the log time uncertain. An exact continuous sighting duration cannot be derived by joining every estimated time.
The claim that someone had a photograph survives in the call transcription, without an authenticated image supplied alongside it. NARCAP also reports employment concerns and restricted cooperation, but says it could not confirm an allegation that management instructed employees not to discuss the event. The public record therefore supports incomplete access to testimony without establishing an organised concealment programme.
Statement and reporting history
7 November 2006: supervisory reports and airline-to-FAA calls enter the operational record.
13 November 2006: NUFORC receives the management-related submission subsequently published in a disguised form.
7 December 2006: NUFORC posts the early employee submissions.
2007: NARCAP publishes its comparison of employee testimony and released operational material.
Complete short entry and editorial notes read. Received 13 November and posted 7 December 2006. NUFORC explicitly revised the narrative to disguise its source, describes possible synthesis and changed the displayed event time. Not an untouched single-person statement or verified observer roster.
Selected witness text and decisive scans in the 155-page reproduction bearing revision 24 July 2007 reviewed; compared with the 128-page edition dated 14 May on NARCAP's website. Narrative roles are used because the revised table misaligns several letter labels. The narrative distinguishes A, B, C and supervisory observers, with missing direct follow-up for C and I. The complete report and original confidential interviews were not reviewed in full.
Original log reproduced as Figure 8; PDF page 25 visually inspected. Entries at 22:45 and 23:03 UTC checked. NARCAP says it received the certified copy on 5 March 2007 under request 2007-001234GL. The log records a relayed report and tower non-observation, not a radar-verified object.
Tables 3–6 and accompanying departure-radio passage, PDF pages 34–41, read; telephone tables visually checked. Parentheses include investigators' comments and uncertain transcription. Original audio not auditioned. Printed time conversions and first-call/log timing contain inconsistencies, so exact visual chronology is not inferred from them.
Anonymous ramp and maintenance observers, including mechanics taxiing an empty aircraft; excludes supervisory and professional flight-crew accounts
Ground crew witnesses
Ramp and taxi-mechanic observations
NARCAP identifies witness A as a ramp mechanic assisting a Boeing 737-500 pushback at C17. Its account places him beside the aircraft with a connected headset when he looked upward and saw a round appearance. He reported rotation and an estimated altitude of 500–1,000 feet, then alerted airline operations and the nearby cockpit crew. These estimates describe his impression from below, without a measured range or physical diameter.
NUFORC report 53541 comes from a self-described taxi mechanic moving a Boeing 777 from the international terminal towards a maintenance hangar. He says a pilot's company-radio comment prompted attention and that he and his colleague saw a dark grey, hazy, round appearance while passing Concourse C. After parking, he saw an approximately circular opening in the cloud where he believed the object had been. His responsibilities involved moving and testing aircraft; this account does not turn the two mechanics into an additional airline flight crew.
NARCAP identifies these maintenance observers as B and C, in the left and right cockpit seats. B's interview describes a stable oval without visible lights or apparent rotation during his brief direct view. He lost the view as the aircraft's orientation changed and says C saw the upward departure. NARCAP reports that C did not answer its questionnaire. B's later view of a cloud opening was personal testimony; his account of C seeing departure remained attributed to his colleague.
A published ground-control exchange records taxi mechanics reporting that they had seen the appearance earlier and had considered a balloon, without certainty. NARCAP regards the speaker as probably B on the basis of matching details. It also mentions another mechanic, I, through B's account, but says I could not be located for interview. This additional lead does not supply another independently reviewed description.
Evidence review
The ramp and taxi accounts offer different sightlines, but their details are not unanimous. A described fast rotation; B did not perceive rotation. B's moving cockpit position restricted his later view, and his colleague's departure observation lacks a separately published interview in the inspected record. NARCAP also notes that some controller comments B recalled were absent from the released ground-control recordings. The recorded dialogue and retrospective recollection consequently need separate treatment when reconstructing the sequence.
The NUFORC taxi submission's total duration and observer-count fields exceed the individual viewing period described in NARCAP's interview. They cannot establish an uninterrupted observation or a verified population of witnesses. NARCAP's longer combined duration is a reconstruction from estimated times and taxi movements. Its derived object dimensions additionally assume a position relative to the gate and cloud base.
The recorded balloon suggestion belongs to the reporting mechanics themselves. NARCAP subsequently argued against a meteorological balloon using launch, wind and reported-motion considerations. That assessment concerns a particular proposed source; it does not identify every possible lightweight airborne object. No matched balloon or other conventional target was established in the material reviewed.
Statement and reporting history
7 November 2006: ramp and maintenance personnel report a visual appearance and discuss it through operational channels.
21 November 2006: NUFORC receives the taxi-mechanic account.
24 November 2006: NARCAP sends C a questionnaire, according to its published account; no answer is reported.
2007: the investigation compares the mechanic's submission, interview, taxi movements and ground-control dialogue.
Complete short entry read. Received 21 November and posted 7 December 2006. Separates company-radio information, the mechanic's own view and the later cloud opening. The author is anonymous; occupational duties are self-described.
Selected witness text and decisive scans in the 155-page reproduction bearing revision 24 July 2007 reviewed; compared with the 128-page edition dated 14 May on NARCAP's website. Narrative roles are used because the revised table misaligns several letter labels. The narrative distinguishes A, B, C and supervisory observers, with missing direct follow-up for C and I. The complete report and original confidential interviews were not reviewed in full.
Tables 3–6 and accompanying departure-radio passage, PDF pages 34–41, read; telephone tables visually checked. Parentheses include investigators' comments and uncertain transcription. Original audio not auditioned. Printed time conversions and first-call/log timing contain inconsistencies, so exact visual chronology is not inferred from them.
Reported Boeing 737 flight-crew observation and separate aircraft checks; excludes the Boeing 777 taxi mechanics
Airport and airline pilots
The reported flight crew and outside check
NARCAP's report summarises Jon Hilkevitch interviewing the Boeing 737-500 first officer, labelled H, at C17. It attributes to him a stable, round, dirty-aluminium-coloured appearance, silence and roughly five minutes of viewing. The summary says both crew members opened side windows and neither took a photograph; the captain declined interview. This is a published account of an anonymous first-officer interview, with the captain's participation described through that reporting chain.
NARCAP itself says it could not obtain the identity of United Flight 446's cockpit crew through the company. The absence of public crew identification and NARCAP's lack of direct access limit comparison of the interview attributed to Hilkevitch with a complete pilot statement or verified crew record. The mechanic's account and ramp-tower telephone calls separately preserve reports of pilot involvement.
The published FAA transcription contains a later request for Gateway 5668 to look above the United concourse. Its pilot reports seeing nothing identifiable. The same sequence then records taxi mechanics saying they had seen it about half an hour earlier. United 446's reproduced departure transmission contains no mention of the unusual appearance. Neither exchange supplies an airborne pilot's positive observation of the claimed cloud penetration.
Evidence review
The pilot evidence has more substance than a general workplace rumour, because it includes an attributed interview summary as well as same-day operational relays. Its public provenance is nevertheless narrower than a named, signed or fully published cockpit interview. The report's age and flight-hour figures remain assertions in that summary, without personnel records inspected here.
Gateway's negative response occurred during a later search and cannot establish what had been visible earlier. Silence about the phenomenon on United 446's departure frequency likewise supplies no description of the earlier gate view. The inspected record contains no confirmed observation from an approaching aircraft above the cloud layer; NARCAP expressly treats that possibility as unconfirmed.
Statement and reporting history
7 November 2006: ground employees and ramp-tower callers report pilot involvement; FAA ground control later asks Gateway 5668 to look.
1 January 2007: Hilkevitch's Chicago Tribune reporting brings the accounts to wider attention, as documented in NARCAP's report.
2007: NARCAP publishes the first-officer interview summary while recording its own unsuccessful attempt to obtain the crew identity.
PDF page 16 visually inspected for the interview attributed to Hilkevitch; page 19 read for NARCAP's unsuccessful crew-identification request. No original full pilot interview, crew roster or personnel credentials inspected. The report's summary is evidence of attributed testimony, not a new interview conducted in this review.
Complete short entry read. Received 21 November and posted 7 December 2006. Separates company-radio information, the mechanic's own view and the later cloud opening. The author is anonymous; occupational duties are self-described.
Tables 3–6 and accompanying departure-radio passage, PDF pages 34–41, read; telephone tables visually checked. Parentheses include investigators' comments and uncertain transcription. Original audio not auditioned. Printed time conversions and first-call/log timing contain inconsistencies, so exact visual chronology is not inferred from them.
The observation, cloud claim and instrument record
The occupational labels describe parts of one reporting network. Anonymous submissions, company-radio alerts and later interviews cannot simply be added together. NUFORC's management entry was deliberately disguised and may be composite; its taxi-mechanic entry is reused within NARCAP's investigation. The FAA calls document that the report was active on 7 November 2006, while the visual descriptions remain those of their attributed observers.
The cloud opening is a reported visual effect rather than a photographed physical trace. The taxi mechanic personally described seeing it after parking, but relayed his colleague's upward-departure observation. Other witnesses supplied departure descriptions from different positions. Joining these into an object that created a measured cylindrical channel requires assumptions about shared identity, position, timing and cloud structure that the records do not independently measure.
NARCAP's cloud section, by Kim Efishoff and Larry Lemke, rejects an ice-precipitation explanation on its reconstruction of the weather and proposes rapid droplet evaporation. Its energy calculations use assumed cloud properties and object movement; the suggested electromagnetic heating is an explanatory model, not detected radiation. The authors' conclusion that an externally real object or phenomenon produced the opening rests on accepting the reported sequence and their model; the report does not resolve whether the source was solid or ephemeral. The investigation did not obtain an instrument record of heat deposition or cloud microphysics at that point. The weather reconstruction draws on local surface and ceiling reports together with a later Davenport sounding about 140 miles away and regional satellite information. These inputs do not measure temperature or droplet conditions inside the reported opening.
Hole-punch clouds also have a documented conventional mechanism. NASA's account of aircraft-induced examples explains how expansion around wings or propellers cools air, freezes supercooled droplets and promotes cloud clearing. That mechanism requires suitable cold-cloud conditions. Its existence is relevant to interpreting a reported opening, but it does not by itself identify the O'Hare appearance. NARCAP's rejection concerns its inferred local conditions; neither the general mechanism nor the report's alternative supplies a directly observed cause for this encounter.
The official radar material does not establish a target over C17. NARCAP's Puckett and Shough analyses of released primary radar plots found no corresponding position or departure track in the intervals they analysed. Shough regarded a striking alignment of other plots as most economically explained by coincidence, not extraordinary speed. He separately examined weather-radar echoes and identified several ordinary sources and coarse-resolution limitations. Haines interpreted the absence of a corresponding return as a possible safety-detection problem. That institutional recommendation is distinct from the underlying negative and ambiguous instrument findings.
The FAA's weather suggestion also needs its original scope. NARCAP reproduces spokeswoman Elizabeth Isham Cory's explanation involving low cloud and airport lights; this is a reported public position, not a detailed fallstreak-cloud investigation in the inspected FAA log. The balloon suggestion recorded in the FAA calls, the report's competing cloud models and the absence of a matching radar track leave different portions of the narrative open to interpretation. The available evidence supports a documented unusual-observation report without resolving physical dimensions, departure speed or cause.
Key dates
7 November 2006
Airline employees report an unusual appearance near Gate C17 and contact the FAA tower. Their individual times and viewing periods differ.
7 November 2006, 22:45 UTC
The reproduced FAA facility log records Sue's ramp-tower inquiry and the reply that tower personnel had not seen the reported disc. The published first-call transcription gives an earlier local time.
7 November 2006, 23:03 UTC
The facility log records quality-assurance closure of the disc report.
13–21 November 2006
NUFORC receives the management-related and taxi-mechanic submissions, later published with different anonymity and editorial treatments.
18 November 2006
Haines requests FAA communications, logs and radar information, according to the investigation's request history.
7 December 2006
NUFORC posts both early submissions.
1 January 2007
The Chicago Tribune publishes Hilkevitch's reporting, subsequently cited throughout the NARCAP investigation.
February–April 2007
NARCAP receives successive radar, log and audio releases and requests missing communications, according to its published FOIA history.
14 May–24 July 2007
Surviving NARCAP editions document the investigation and its revision. Their models and source summaries remain distinct from the November 2006 records they reproduce.
Complete short entry and editorial notes read. Received 13 November and posted 7 December 2006. NUFORC explicitly revised the narrative to disguise its source, describes possible synthesis and changed the displayed event time. Not an untouched single-person statement or verified observer roster.
Complete short entry read. Received 21 November and posted 7 December 2006. Separates company-radio information, the mechanic's own view and the later cloud opening. The author is anonymous; occupational duties are self-described.
Selected witness text and decisive scans in the 155-page reproduction bearing revision 24 July 2007 reviewed; compared with the 128-page edition dated 14 May on NARCAP's website. Narrative roles are used because the revised table misaligns several letter labels. The narrative distinguishes A, B, C and supervisory observers, with missing direct follow-up for C and I. The complete report and original confidential interviews were not reviewed in full.
PDF page 16 visually inspected for the interview attributed to Hilkevitch; page 19 read for NARCAP's unsuccessful crew-identification request. No original full pilot interview, crew roster or personnel credentials inspected. The report's summary is evidence of attributed testimony, not a new interview conducted in this review.
Original log reproduced as Figure 8; PDF page 25 visually inspected. Entries at 22:45 and 23:03 UTC checked. NARCAP says it received the certified copy on 5 March 2007 under request 2007-001234GL. The log records a relayed report and tower non-observation, not a radar-verified object.
Tables 3–6 and accompanying departure-radio passage, PDF pages 34–41, read; telephone tables visually checked. Parentheses include investigators' comments and uncertain transcription. Original audio not auditioned. Printed time conversions and first-call/log timing contain inconsistencies, so exact visual chronology is not inferred from them.
Selected weather assumptions, mechanism discussion and conclusions at PDF pages 47–49 and 53–54 read. Evaporation and electromagnetic energy are model proposals, not measured emissions. No complete independent meteorological or energy-budget reproduction performed.
Selected weather-radar limits at PDF pages 79–83 and primary-plot discussion at pages 84–91 read. Puckett and Shough found no plot matching the claimed C17 position or departure; Shough favoured coincidence for the distant plot alignment. Original NTAP files and radar software were not inspected or independently rerun.
Substantive December 2010 explanation read, describing photographed West Virginia examples and the cooling/freezing mechanism with attribution to Andrew Heymsfield's work. General physical context, not an investigation or identification of the O'Hare report.