R e s e a r c h
Sources & materials
As always, it's vital that we work with the most reliable information. Usually, this will mean that we favour a contemporaneous or near-contemporaneous account over one set down long after the event when witnesses may have been exposed to speculations and questions that can influence their recall.
Some discussions of this case incorporate material from accounts set down years later, for example an article by Capt. HOWARD that appeared in the magazine Flying Saucer Review (HOWARD, 1982). There are significant details in this late account which are not to be found in the earliest available published accounts.
The primary narrative sources used here are Capt. HOWARD's early first person account  from the British magazine Everybody's Weekly (HOWARD, 1954) including a series of contemporaneous drawings from Capt. HOWARD's logbook (see previous Chapter) and his Voyage Report  [extracted in Appendix B(i)]. Other primary sources include the 29pp USAF Project Blue Book case file.
Some 14 years after the event G. David THAYER, an ESSA radar propagation expert, considered this observation for the USAF-sponsored Colorado University study (known as the Condon Report, see: THAYER, 1970) basing his analysis on an 8pp "UFO Sighting Report" form filled out by Capt. HOWARD on December 1, 1967 at the request of the Colorado project [see also Appendix B(ii)]. THAYER pointed to several features very typical of mirage, but had difficulty making the theory fit perfectly . He famously concluded that it was some type of natural atmospheric phenomenon "apparently so rare that it has never been reported before or since" .
However a very similar observation made near Zanthus, Southwestern Austalia, in August 1968 by a civil aircrew in similar circustances  suggests a very similar phenomenon. There are in fact parallels with several other observations, most of them little-known but a few of them prominent in the popular literature such as the very influential sighting by highly-respected United Airlines pilot Capt. E. J. SMITH and his crew on July 4, 1947 (only days after the first "saucers" were seen by private pilot Kenneth ARNOLD) of a row of dark "discs" against the sunset sky over the mountains of Oregon . A similar atmospheric-optical mechanism might be indicated.
Extant meteorological data for the region of Newfoundland and Quebec are sparse. More than forty years ago THAYER (1970) lamented the "very little meteorological data available" and was able to cite none. McDONALD, an atmospheric physicist, referenced weather maps for that day, saying that "although there are not many reports in that part of Canada I get the impression there would not have been an extensive amount of cloud cover" (1969) and that they indicated "fair weather" and good visibility consistent with Capt. HOWARD's report (1968), but he did not reproduce them. Probably these were the US Weather Bureau Daily Weather Maps (see later). As for upper-air radiosonde readings, apart from a US Weather Bureau chart of the 500 mbar pressure surface, we have none and thus no means of inspecting the vertical temperature profile of the atmosphere. All that survives is a tantalising comment in a telex from Pepperrel AFB (adjacent to Goose Bay), timed 17:35 Z July 1, 1954 that "A TEMPERATURE INVERSION IN THE REFERENCED AREA MADE [MIRAGE] POSSIBLE". No balloon data appear in the file so we have no idea what levels (if any) or date/time this information refers to. The telex ends with the assurance that complete data are to follow. They never did, or if they did they don't survive in the file. There is only a terse surface weather report from the 641st AC&W Squadron, Goose Bay. Thanks to the Canadian Weather Office some hourly and daily surface weather reports have been located for Goose and a few other scattered locations in Quebec, as discussed later (see Chapter 4.3 and Appendix A).
There are several other oddities worth noting in the Project Blue Book file. On one typed sheet a brief reference is made to study of a photograph. There is no explanation, and the "No" box is properly checked in the "photos" section of the Project 10073 Record Card. No other known source refers to photographs in connection with this case.
It's possible that the photo is connected instead with another report in the file, forwarded to ATIC from HQ, USAF, Washington on July 2 . This report was a telex from a naval ice breaker, the USS EDISTO, reporting an interesting observation on the same night, June 30, at 01:15 Z, actually during the BOAC sighting, but from 55°55' N/58°10' W. This is about 60 miles off the east coast of Labrador, some 300 miles NE of the BOAC sighting area, and the sighting direction was SE across the sea
At an azimuth of 140° True and at 20° elevation a "bright reddish-yellow object" was seen changing shape, looking first like "a jellyfish swimming to the westward" and then like "a dart". It was "identified at the time as the planet Mars" according to the telex, and it was noted that "mirage effect had been pronounced during the day in its field".
Mars was indeed close to that bearing at 148° but only a couple of degrees above the horizon at that time, so a factor-10 error in elevation needs to be assumed. This would also be implied by the mirage interpretation since a 20° angle is far too high for mirage. Gross exaggerations in horizon elevation are commonplace even among experienced observers, and no other obvious astronomical source was in that part of the sky. So far so good, and taken together with the Pepperrell AFB telex cited above the USS EDISTO sighting is evidence that low-level inversion conditions might have existed that evening over a very wide area around Newfoundland. This is not by any means direct evidence of the temperature profile at 19,000 ft but is at least suggestive .
However Blue Book were not content with so modest an inference and instead pounced on the USS EDISTO telex to "explain" the BOAC sighting, even though the latter was a sighting of black silhouettes next to the sun on a bearing 150° away from the position of Mars. Incredibly, "the Planet Mars" is the official conclusion on the Project 10073 Record Card for Capt. HOWARD's sighting, and this is the conclusion that was sent to the British Air Ministry who (the file reveals) had been in contact with ATIC via HQ USAF and made an official request for copies of "interrogation reports" and "any other info" generated by the ATIC investigation. Disingenuously, the Blue Book file summary describes the sighting as "a type of wavering light formation", presumably so as to make the Mars story sound less absurd .
Notes & references
 The narrative is "by Capt. James Howard, a B.O.A.C. pilot, as told to Graham Fisher", but journalistic influence appears to be minimal (or merely nominal - in those days of "closed shop" trades unionism a staff byline would probably have been necessary). According to a letter from R.H.B. WINDER (an engineer on the editorial staff of British magazine Flying Saucer Review) dated August 30, 1967 to Robert J. LOW, Colorado University UFO Project Coordinator, covering transmissal of a copy of this Everybody's article obtained from Capt. HOWARD, the latter personally endorsed the account as "the most accurate of the published accounts and (...) a faithful record of his experience" (original letter in Colorado U. Project files; Library of the American Philosophical Society, Philadelphia; copy courtesy of Dr. David CLARKE).
 David THAYER has confirmed to the present author that this was the sole source made available to him at the time (personal communication, August 13, 2009). He appears to have assumed that it came from Blue Book, but on reflection he points out that his presentation on p. 139 of the Condon Report does not have a "B-number" which would identify a Blue Book source. Indeed it is the only case in THAYER's chapter which doesn't have any case number (if not a B-number it should have an N-, C- or X number). The reason for this is unclear, but it appears that the materials in the Project case file were assembled by Robert LOW, Project Coordinator, via visits and correspondence with intermediaries in the UK during 1967. See note .
 We will show that this is at least in part due to problems with the source material. One of several confusions arising from the UFO Project Sighting Report Form is the duration, which passed into the literature via THAYER's account as 01:05 Z - 01:27 Z, introducing a 4 minute discrepancy which has puzzled some commentators. The error appears to be in Capt. HOWARD's 1967 recollection. The times he gave in 1954, quoting from the Navigation Log (see p. 6), match the time recorded in contemporary USAF telexes (although ironically Blue Book's Project 10073 Record Card, whilst getting the 18-minute duration correct, perpetuates a different 4-minute discrepancy by quoting an incorrect start time of 01:09 Z from the original EMERGENCY priority telex from 641st AC&W, Goose, which was corrected in a later telex timed at about 03:30 Z).
 Appendix C contains a small but significant number of similar observations catalogued by Wim VAN UTRECHT. The Zanthus case (case #5 in this catalogue) was known to Dr. James E. McDONALD and referenced by him in his January 29, 1969 letter to James HOWARD (Colorado U. project files; Library of the APS, Philadelphia) with the comment that "it paralleled your experience closely".
 Notably, the detail of this telex was leaked to the press simultaneously, appearing in the following morning's July 3 edition of the Washington DC Star (GILES, John A., "Mirage Called Possible Answer on Objects Seen by Flyers") along with another from NEAC, Pepperell AFB (Goose) also suggesting mirage. The article erroneously gives the Edisto's position as "in Ungava Bay", north of Quebec and generally NNW of the Stratocruiser, a ~350 mile error which has the effect of placing the USS Edisto nearer the scene of the action.
 The Goose weather report shows a somewhat elevated surface atmospheric pressure NE of the sighting location of 30.13 inches of mercury (1020.32 mbar) and Quebec weather reports NW of the flight track record an unusually warm afternoon, possibly consistent with an anticyclonic inversion [see Chapter 4.3 and Appendix A (vi)].
 This was the Dark Ages of an emasculated Blue Book under Capt. Charles HARDIN, keen to drive down "unexplained" statistics following the CIA-sponsored Robertson Panel of 1953. But as Brad SPARKS points out (personal communication, August 7, 2009) it is interesting that by this date Blue Book had been shifted from the ATIC Aircraft & Missiles Branch over to the security-sensitive Electronic Intelligence Branch (office symbol ATIAE, for cover purposes called the "Electronics Branch,") under Lt. Col. Harry C. JOHNSTON, and that two British RAF intelligence officers, Sq Ldrs WAINWRIGHT and BENTLEY (assigned to the Pentagon at AFOIN Military Capabilities Division [East]/ Future Estimates Branch AFOIN-2C1) were still liaising with ATIC to pursue this case as late as mid-October. What is equally interesting given this apparent level of interest, in the context of possible new Soviet military activities, is that in March 1955 the UK MoD Deputy Directorate of Intelligence DDI (Tech) prepared a short RESTRICTED Air Ministry Secret Intelligence Summary (AMSIS) for the Assistant Chief of Air Staff (Intelligence) which concluded: