This report presents the results of an investigation into an interesting incident at O'Hare International Airport (ORD) on November 7, 2006 at about 1615 hrs (4:15 pm) CST that had definite safety implications. A number of highly reliable airline employees and others reported seeing a round, revolving, gray, metallic appearing object [hereafter called an Unidentified Aerial Phenomenon (UAP)] hovering approximately above United Airline's Gate C17 in Concourse C at an altitude less than 1,900 feet above ground level (AGL) and departing sometime between 4:18 and 4:33 pm. Since two United taxi mechanics reported seeing the object sometime after 4:00 pm the object could have been present for at least eighteen minutes or more.
The following subjects are discussed here: Description of eye witness accounts, An overview of O'Hare International Airport and its aviation operations, visibility from the control tower, weather conditions, the reported hole in the cloud allegedly caused by the UAP, radar technical considerations and possible primary contacts, safety implications of the incident, and a summary.
Appendices also present a discussion of hoax data, press coverage of the event, reports of UAP made by other alleged witnesses in the area on that day, a description of typical cockpit duties during an approach, landing, and taxi to gate and other relevant documents.
Based on multiple eye witness testimony the UAP would have ranged in size from about twenty-two to eighty eight feet diameter. It accelerated at a steep inclined angle through the 1,900 ft cloud base leaving a round hole approximately its own size that lasted for as long as fourteen minutes. This is suggestive of a super heated object or otherwise radiated (microwave) heat energy around 9.4 kJ/m3. According to the FAA nothing was detected by radar at this location or time of day or seen by air traffic controllers from the main tower.
An examination of the radar data supplied by the FAA confirmed the first claim. however, an FAA inbound ground controller remarked about the "UFO" (UAP) at about 3:58:09 pm, long before the object had departed. No reference to a UAP is made by any inbound or outbound flight crew other than two United maintenance taxi mechanics moving an empty airplane to the maintenance hanger on the north side of the airport. Of course this does not mean that there was no object present but only that these flight crew did not discuss it over the radio.
Careful analysis of the situation suggest that a potentially significant air safety problem existed at O'Hare International Airport on the afternoon of November 7, 2006. Anytime an airborne object can hover for several minutes over a busy airport but not be registered on radar or seen visually from the control tower, constitutes a potential threat to flight safety. The identity of the UAP remains unknown. An official government inquiry should be carried out to evaluate whether or not current sensing technologies are adequate to insure against a future incident such as this.
