1759 April 27 — 4:00 p.m. Following a clap of thunder, a flat, pale object is seen “dancing” in the sky over Longdon, Somerset, UK. It is joined by three similar objects, all of which move from west to east for 30 seconds and disappear in a cloud.

1948 April 27–28 — Physicist Joseph Kaplan, a member of the USAF Scientific Advisory Board, visits the Kirtland AFB Office of Special Investigations, AEC’s Sandia Base, and Los Alamos, under orders from Theodore Von Kármán, chairman of the USAF Scientific Advisory Board, to review UFO reports and investigations from the area. Kaplan and Lincoln LaPaz meet with security personnel at Los Alamos. Kaplan reports that “these occurrences relate to the National Defense of the United States” and should be investigated scientifically.”

1949 April 27 — Rees, Kaplan, and LaPaz brief Armed Forces Special Weapons Project personnel at Sandia Base. LaPaz outlines plans for a network of visual, photographic, spectrographic, and radar observations covering Los Alamos, Sandia, and White Sands. Scientist William D. Crozier of the New Mexico School of Mines offers to handle air sampling. Rees urges that the Killeen Base in Texas be included. Kaplan, who says the project is “of extreme importance” because “these occurrences relate to the National Defense of the United States,” recommends LaPaz to handle the project. http://www.nicap.org/nmexico/lightphen3.htm ; http://www.nicap.org/docs/490512_AFOSI_Rees_%20memo_o%20Kaplan_visit.pdf ; https://sohp.us/collections/ufos-a-history/pdf/GROSS-1949-Jan-Jun-SN.pdf 

1949 April 27 — USAF Directorate of Intelligence briefs the USAF Deputy Chief of Staff for Operations on UFOs. “Investigations continue in an effort to find definite explanations for the many unidentified aerial objects which have been reported during the past two years.” http://www.nicap.org/docs/project1947.com_fig_airbrf.pdf 

1949 April 27 — USAF Director of Intelligence Charles Cabell sends a report on “Unidentified Aerial Objects: The Problem” to the Joint Intelligence Committee. It summarizes the history of Project Sign up to its redesignation as Grudge and adds an appendix on “Unidentified Aerial Objects: Fact and Discussion,” which is basically a short version of the sanitized February 11 Sign report, with some green fireball information added. It recommends sending reports of unidentified “light phenomena” to the scientific community and reports of “atomic powered craft of unusual design” to the AEC. It concludes that “There are numerous reports from reliable and competent observers for which a conclusive explanation has not been made” and that some “involve configurations and described performance which might conceivably represent an advanced aerodynamical development. A few unexplained incidents surpass these limits of credulity. It is unlikely that a foreign power would expose a superior aerial weapon by a prolonged ineffectual penetration of the United States.” This essentially resurrects the ETH as a possibility, without clearly stating it. http://www.nicap.org/dean/JIC_report/project1947.com_fig_jic.pdf ; http://www.cufos.org/pdfs/IUR_article1.pdf 

1949 April 27 — A 22-page memorandum for the press (629-49) on “Project Saucer” is released by the Pentagon Office of Public Information, scheduled deliberately to coincide with part one of Shalett’s article in the Saturday Evening Post. The writer is unknown, but it is more pro-ETH than the current Project Grudge mentality, listing several solid and dramatic cases. It concludes: “The ‘saucers’ are not a joke. Neither are they a cause for alarm to the population.” The discrepancy between Shalett’s mostly dismissive tone and the positivity of the Project Saucer statement causes Maj. Donald E. Keyhoe to wonder if there is a major disagreement about UFOs within the Air Force. http://www.nicap.org/docs/SaucerRptApr1949.pdf 

1949 April 27 — 9:20 p.m. Two Army patrolmen southeast of Killeen Base, Texas, see a blinking violet light no more than 1.5 inches in diameter and only 10–12 feet from them, 6–7 feet above the ground. During the 60-second observation, the light passes through the branches of a tree. At 9:25 p.m., 2 miles away, four Army soldiers see a 4-inch light with a 2–4-inch metallic cone attached to the back. It silently approaches them in a level flight at 60–70 mph. It disappears to the southwest at a distance of 150 feet. At about 9:37 p.m., a 2-inch-wide white light appears 100 feet away to the northwest, flying in a zig-zag fashion in a level path 6 feet above the ground. It vanishes abruptly. A third light shows up at 9:39 p.m. in the west-southwest. http://www.nicap.org/490427camphood_dir.htm

1950 April 27 — While preparing for an MX-776A Shrike air-to-ground missile test at White Sands Proving Ground, New Mexico, Charles Riggs, a member of the Project Twinkle cinetheodolite camera crew supplied by Land-Air Inc., sees, tracks, and manages to film four high-flying objects streaking across the sky. Another station also tracks the objects. The photos show only a smudgy dark object, but the triangulation results in a calculation by mathematician Wilbur L. Mitchell and Capt. Perry Bryant of the objects’ size as 30 feet in diameter and 150,000 feet in altitude. http://www.nicap.org/500427whitesands_dir.htm ; https://sohp.us/Sign-Historical-Group-Workshop-Proceedings.pdf 

1950April 27 — 8:25 p.m. TWA Flight 117 pilot Capt. Robert Adickes and Flight Officer Robert F. Manning are flying near Goshen, Indiana, when they see a bright-red disc-shaped UFO behind their DC-3. It overtakes the plane in about 2 minutes. Stewardess Gloria Henshaw and 11 passengers (including Boeing engineers C. H. Jenkins and Dean C. Bourland and executives E. J. Fitzgerald and S. N. Miller) also see the object. It veers off at 400 mph, drops down to 1,500 feet, and disappears. http://www.nicap.org/500427goshen_dir.htm

1967 April 27 — 9:00 p.m. Clifton N. Crowder, manager of the Mobil Chemical Company warehouse in South Hill, Virginia, leaves the warehouse and starts home. About 50–75 yards down a narrow asphalt highway his headlights fall on an object 400 feet away on the road ahead. It is pewter-colored, shaped like a storage tank, about 12 feet in diameter, and 15–16 feet high. It is standing on legs about 3–3.5 feet long. He switches to his bright lights and the object belches a white burst of flame from the bottom and ascends rapidly. Meanwhile, the road is on fire. After it dies out, Crowder drives to South Hill and contacts police. They return and find a kidney-shaped black spot on the road, about 3 feet wide at the widest point. Two spike holes about 6 inches apart are also found, as well as four marks where the landing gear were, about 11–12 feet apart.

1968 April 27 — The May 14 issue of Look magazine contains John Fuller’s article on the Low memo and the near-mutiny at the Colorado project, “Flying Saucer Fiasco.” http://www.nicap.org/fiasco.htm

1986 April 27 — J. Allen Hynek dies in Scottsdale, Arizona, from a malignant brain tumor.

2014 April 27 — The crew of a F/A-18F from Strike Fighter Squadron 11 (VFA-11), flying out of NAS Ocean in Virginia Beach and operating in the W-72 warning area, encounters an unknown aerial device. This report is the most spartan in its details of the three, but describes a “near mid-air collision with balloon-like object.”

2020 April 27 — The Pentagon officially releases the three videos showing UFOs that were previously released between December 2017 and March 2018 by the private company To the Stars Academy of Arts and Sciences. https://www.cnn.com/2020/04/27/politics/pentagon-ufo-videos/index.html