733667-001-020
AI Summary
This document details the radar analysis and eyewitness accounts related to the Japan Airlines Flight 1628 incident on November 17, 1986, where the crew reported being followed by unidentified flying objects. The FAA's investigation revealed uncorrelated radar signals, which were attributed to radar quirks rather than a separate object.
Key Findings
- Radar data indicated uncorrelated primary and beacon targets during the JAL flight. - FAA experts confirmed that the radar signals were normal for the area and did not show abnormalities. - The crew reported seeing lights that performed unusual maneuvers, which they could not identify. - The FAA concluded that the radar returns could be attributed to a split image of the JAL 747, not a separate object.
OCR Text
:";: ~?-i;:{~J. ' ' . > ·' " ,<. ' ' .. ' ' .. _, . . . ; ~. ' .. '.•. : . . , .. . " ' \>I I : .. ·~:, '. ' ' .. ~ ,. ' . ,, . ! ....... ' • \ • './ : :~ ... , · • 1' . ...... , . '·" . ."': ' ' ,.· ·.·1'·:: ·\ ·,, , .· . . .t. : : • / , . 1 ' . ·· . :.· '.'' ',r', .r • . .' · .. '' ' .'·, .· , .• ~'. , :, ... : • ( , • . · ' '1 ' 't-I .') , ' , •' f'~i ,' '1~ . I .-:. . . . ~· ·. ' , ... '.' ,·_ ·.:•\ .< _, ·, .. · ·" , . ... \ I'• • · 1 l J. , I , ... i'• '·i • I I~ . ; ' ·,· I, \ "' ' •, f,,~ I ~ 't _, •. ~ • IC I,,"'." . .... · • ' ,,' 1 . ·.· .; :> .. · ·'~ "'· Paul Steucke FAA Public Affairs 701 C Street, Box 14 Anch. AK 99513 March 5 , 1987 UNCORRELATED RADAR SIGNALS Radar data received by the FAA and used to track Japan Airlines flight 1628 on the night of the November 17, 1986, was retained by FAA. Review of this radar data by FAA experts using identical equipment at the FAA's research technical center in Atlantic City, New Jersey, revealed that the radar system was receiving what is called an "uncorrelated primary and beacon target". This electronic phenomena is not unusual according to Steucke who said, "It is unfortunate that the uncorrelated target phenomena. occurred just when a pilot was reporting seeing something outside his aircraft. The controller's statements, released by the FAA, indicate that they thought there might be another aircraft or object in the area of the JAL flight. Steucke said, "The controllers were doing their job right because they have to work with what is right there in front of them on the screen, especially when you have a Captain that is reporting "other traffic" in his illiTlediate area. The radar data they had was one target, moving slowly across the radar screen. They don't have the benefit of "monday morning quarterbacking" with multiple radar images as was the case in regenerating the radar data." Review of the radar data by FAA experts revealed the "uncorrelated target" phenomena. FAA electronic technicians explained that an "uncorrelated primary and beacon target" on the radar screen occurs when the radar energy that is sent up toward the aircraft, (primary signal) returns to the radar receiver along with the aircraft transponder (beacon) signal and the two do not match up as being at the same exact location. II IJ IJ / UNCORRELATED RADAR SIGNALS An "uncorrelated primary and beacon(secondary) return on a radar screen occurs when the radar energy that is sent up toward the aircraft (primary signal) returns off the surface of the aircraft at a slightly different moment than fhe beacon (secondary) transponder signal and the two do not match up as being at the same place or same computer radar cell. --~~~~~~~~111L--~~~~~~~~~ --RADAR COMPUTER CELL, 1/4 MILE-- --,/'- SECONDARY RADAR RETURN (Beacon) (Transponder) --11 FAA RADAR Drawing by Paul Steucke March 5 , 1987 SAME AIRCRAFT (Skin- Surface) RADAR CELL =PRIMARY RADAR RETURN =SECONDARY RADAR RETURN =CORRELATED RETURN (Combined Return) =UNCORRELATED RETURN / Memorandum U.S. Department of Transportation Federal Aviation Administration Subject: INFORMATION: Description of Radar Split Image; AAL-5 Meno of 2/5/87 From Manager, Airway Facilities Division, AAL-400 To Public Affairs Officer, AAL-5 Date: Reply to Attn. of FEB 2 7 1987 'Ihis letter transmits our analysis of the radar targets associated with JAL flight 1628, on November 17, 1986, arrl supplements discussions we have had~ what has been referred. to as "split ima.ges". We concur with the interpretation provided to you by the Alaskan Region Air Traffic Division. 'Ihe attached Analysis of Uncorrelated Primacy arrl Beacon Targets by Dennis Sima.ntel covers the subject in :rrore detail, an:l addresses the questions raised in your letter. Paul, I appreciate the team approach you have taken to more fully un:ierstarrl a complex issue. 'Ihe issue is an excellent example of how "interdeperrlent" we are. If we can provide any more infonnation, please 7LiC. David F. Morse Attaclnrent ......., -..a ::0 ~ ,....,, rn CD ·= CJ ....... rn - -< ,_ ni CJ r..._.J ··-.. , / ANALYSIS OF UNCORRELATED PRIMARY AND BEACON TARGETS (JAL-1628, 11/17/86 AKST) Approximately 61 minutes of data was extracted from the EARTS CDR printouts relating to the November 18 incident involving JAL-1628 and the alleged UFO sighting. Review of the data involving this incident did not show any abnormalities that could be associated with any type of target as indicated by the pilot-of JAL-1628. Radar returns from the aircraft and surrounding terrain vary with the different segments of the flight, but are considered normal for the area. Returns relating to the incident can be categorized as three types: primary radar reinforced by a beacon reply (primary radar returns and beacon returns are both evident in the same 1/4 mile range c…
Metadata
- Agency
- National Archives and Records Administration
- Classification
- UNCLASSIFIED
- Department
- National Archives and Records Administration
- Catalog source
- View NARA catalog record
NARA Source
- NAID
- 733667
- File
- 733667-001-020.pdf
- Type
- application/pdf
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