United Airlines

A United Airlines aircraft maintenance officer working at a maintenance facility in London, England, receives a suspicious satellite phone call from an unknown aircraft, apparently made by the plane’s pilot, who sounds distraught, possibly as if he is being choked.
Caller Sounds Strange, Makes No Sense – The call lasts for about seven or eight sentences, but the maintenance officer is unable to make sense of what it is about. He will later recall that the caller sounds strange, and tell the 9/11 Commission that this is the “only phone call that he’d ever received of that nature in the 10 years he’s been on the job for United.” The maintenance officer presumes that the caller is the plane’s pilot, because this specific type of satellite phone call can only be made from the flight deck of a commercial airliner. However, the caller’s manner of talking is not professional. The number for the London facility would not have been programmed into the phone, so the caller would have needed to type it in.
Caller Possibly Being Choked – The maintenance officer subsequently contacts the United Airlines System Aircraft Maintenance Control (SAMC) at San Francisco International Airport to report the strange call. The FBI is already at the SAMC and is made aware of his report. It is informed that the maintenance officer has said the caller from the plane “sounded as if they were being choked.” However, when he is interviewed by the 9/11 Commission in November 2003, the maintenance officer will state that “it is difficult to say whether or not the pilot was getting choked.” He will say he “doesn’t believe this to be the case and doesn’t recall reporting this,” although he will indicate that it is “possible he previously told someone that it sounded like the person was being choked.”
Origin of Call Unknown – The suspicious call comes up as “registration number unknown.” However, the maintenance officer recognizes it as coming from what he will call a “Sat 7 phone,” because, he will say, “the background noise was characteristic of that type of satellite call.” Typically, Boeing 767s and 777s have the equipment to make “Sat 7” calls, although the maintenance officer believes the call is most likely from a 777. The United Airlines legal department will subsequently tell the maintenance officer that “it would be possible to find the station that placed the call, because United must have a record of the phone call.” Satellite phone communication is expensive and each call is itemized when paid for. However, a 9/11 Commission memorandum in November 2003 will state that, at that time, the origin of the call “is still unknown.”
Call Unrelated to Two United Airlines Hijackings – According to the maintenance officer, the call is not tape recorded. But according to Richard Belme, a manager at the SAMC, the call is recorded but then only stored for a short time, maybe three months. The maintenance officer’s notes from this day will subsequently be shredded. The 9/11 Commission will conclude that the suspicious call could not have come from either of the two hijacked United Airlines flights because it does not coincide with the timeframe of those flights. Furthermore, United Airlines Flight 93 was a Boeing 757 and so would not have been equipped with the type of phone necessary to make the call. In mid-2003, the aircraft maintenance officer will be told that “this issue [is] over.” [Federal Bureau of Investigation, 9/11/2001; 9/11 Commission, 11/21/2003 ; 9/11 Commission, 11/21/2003 ]