An early photo of Kenneth Arnold with his 1947 CallAir mountain plane (NC33355) The Singular Adventure of Mr Kenneth Arnold Martin Shough1 © June 2010 The author would like to acknowledge in particular Mary Castner, Barry Greenwood, Patrick Gross, Jean-Pierre Pharabod, Don Ledger, Tom Tulien & Brad Sparks for useful discussions and encouragement and for helping to locate information and sources during the course of this inquiry. 1 UK Research Associate, National Aviation Reporting Centre on Anomalous Phenomena (NARCAP). [email protected] The Singular Adventure of Mr Kenneth Arnold Martin Shough 1) Introduction In one sense it would be true to say that this seminal sighting of nine "peculiar looking aircraft" over the Cascade Mountains of Washington on June 24 1947 (see Appendix 1) needs little introduction. As a result of it pilot and businessman Kenneth Arnold acquired a fame and notoriety far beyond anything he could ever have envisaged when he took off from Chehalis, Washington, and set a course for Yakima in his little CallAir plane that sunny afternoon. News of what the press dubbed "flying saucers" instantly captured the imagination of the world, and reports of things seen in the sky have ever since continued to fuel one of the 20th century's - and now the 21st's - most widespread, most persistent and most influential popular mythologies. Yet that mythology has effloresced into many extraordinary forms, most of which the Kenneth Arnold of 1947 would hardly have recognised as having anything to do with his own puzzling but straighforward observation. And it is necessary to record that despite more than 60 years of sometimes scholarly debate about this hydra-headed mythological monster, its origins remain not well-understood, its meanings controversial, its ultimate cultural value uncertain. Simply by being the first,2 Arnold's experience enjoys a unique position of pre-eminence in both the history and the semiotics of saucerdom, ensuring that his narrative has been retold and repackaged innumerable times. Tracing the progress of that one narrative in its transactions with the co- evolving meta-narrative of our times becomes a social history in itself, one which few historians have tried conscientiously to unravel. Instead, Arnold's narrative or some version of it has all too often been exploited, to the detriment of history and objectivity, as a mere didactic fable enlisted to serve conflicting ideological agendas. A survey of the literature reveals a good deal of inaccuracy and even misrepresentation. Such is to be expected in parts of the enthusiast literature. But all too often it comes from otherwise well- informed and sensible critics from whom one expects better. Perhaps in some cases this reflects the significance of the Arnold sighting as a laboratory for testing our theories about the psychosocial roots of the UFO myth - the issues are exposed with unique clarity, and the stakes are that much higher, the temptation to find confirmation of our prejudices that much greater. Of course most of science and society today remains aloof from the question. Keeping a cautious distance is understandable - a too-impressionable intimacy with the facts has undoubtedly left many enthusiasts in thrall to the myth itself. In-depth studies with no agenda do exist, but they are few and much published material is undeniably discouraging. The unhelpful result is that our opinion- formers by and large keep so prudent a distance from the myth that they cannot clearly make out the nuclear facts at all, leaving the rest of us relying with scant confidence on popular rumour. So there is still a need for a rigorous re-examination of what Arnold said he saw, as well as a mature understanding of the ways in which his story reflected, and was reflected by, the contemporary culture. Obviously no individual analyst can hope to have the 'final word' in such a complex and difficult area. It is an ongoing project, in which the present study is offered as a contribution. Inevitably many of the issues addressed here have been broached by others; but not always fairly, and, when fairly, not always thoroughly or in an integrated way. I hope the reader will also find some fresh perspectives here on what remains a fascinating historical mystery. 2 Not the first sighting of something puzzling in the sky, of course, but the first widely-publicised report of unidentified flying machines in the modern post-war era, and the unarguable trigger for the social phenomenon that ensued. 2) A note on units Belgian researcher Roger Paquay has argued3 that an aviator would automatically use nautical miles, so that all calculations of the sighting geometry assuming distances in statute miles would be in error by a factor 1.15. For example, by adopting Arnold's upper bracket of "25 miles" distance to the objects we could then place them nearly 29 statute miles (45km) away, with consequences for the discernibility of the shapes of objects that might be close to the limit of resolution of the human eye (see Section 8). It doesn't appear that this issue has been raised in earlier literature. The world of modern aviation does widely use knots, of course, and the modern aeronautical charts used for navigation in commercial and military sectors are scaled in nautical miles. But the AAF investigation established early on that Arnold never used specialised aeronautical charts (see Fig.1). Indeed it would be surprising to find a private pilot in the Pacific Northwest thinking in knots and nautical miles in 1947 when US CAA standards were still specified in statute miles per hour and would remain so for another 22 years.4 Even today performance specifications of aircraft are almost universally given in statute mph, followed by km/hr and possibly knots.5 Moreover if Arnold had meant knots because he thought in terms of knots, then one feels that he would have said "knots", but he always used mph.And we have several internal tests that can be done on speeds and distances contained in Arnold's own accounts to prove rather nicely that he was thinking in ordinary statute mph. For example: a) Arnold contrasts the calculated speed of his objects with the fastest jet airspeed thought possible in June 1947, i.e. approaching Mach 1.6 That speed he gives as "in the vicinity of 700mph".7 Interpreted as statute mph this is correct. But 700kt or 805 mph would have been well over the highest possible value of Mach 1, which rises to only ~760mph exactly at sea level b) Arnold describes8 how the speed estimate was made when he landed at Pendleton by transferring the objects' clock-timed 102sec transit between Mt Rainier and Mt Adams onto a map. Taking the distance between points near the summits, said Arnold, they kept coming up with about 1700mph. If he had meant 1700 knots (nearly 2000mph) this would imply that the distance between summits was about 48 nmi (55.2 statute miles). In fact it is only ~41nmi. But 102 seconds over 48 statute miles does equal about 1700mph, proving that they were measuring their map in statute miles.9 3 Roger Paquay, email to Martin Shough 24.11.2009 4 "Prior to 1969, airworthiness standards for civil aircraft in the USA Federal Aviation Regulations specified that distances were to be in statute miles, and speeds in miles per hour. In 1969 these standards] were progressively amended to specify that distances were to be in nautical miles, and speeds in knots." http://en.wikipedia.org/wiki/Knot_(unit)#Aeronautical_terms 5 A 2007 discussion on units on the WikipediaTalk aviation projects page concluded with the following (abbreviated) explanation of why statute miles and mph were settled on for WP:AIR over nm and knots: '. . . practically all aviation reference books intended for a general audience use statute miles; and very many (if not most) books intended for a specialised, enthusiast audience do too. Every one of the English-language books that I use on a regular basis for my contributions gives figures in statute, not nautical, miles. The nautical mile is not only irrelevant to most readers of our articles, but in fact to the specifications of many (I would guess even most) of the aircraft we have articles on . . . . In the US, the Navy always used and continue to use the nm, but the Army/Air Force only introduced it after World War II (1946 or 48?), and civil aviation only started to use it in 1952. Even in 2007, many suppliers and manufacturers in the burgeoning homebuilt market seem to specify in statute miles . . . We cover a lot of pre-1948 US Army/Air Force aircraft and pre-1952 civil ones.' http://en.wikipedia.org/wiki/Wikipedia_talk:WikiProject_Aircraft/Units 6 Yeager's record-breaking experimental X-1 rocket famously did not break this so-called barrier until 4 months later. 7 Arnold, K. and Ray Palmer, The Coming of the Saucers, Amherst 1952 pp.13 8 Arnold, K. and Ray Palmer, The Coming of the Saucers, Amherst 1952 pp.13-14 9 Actually the true distance appears to be a little under 47 statute miles but the thrust of the argument is unaltered. Fig.1 Detail from the report on an interview with Kenneth Arnold, July 12 1947, by Army Air Force Counter Intelligence Corp agent Frank Brown, July 16 1947 (Project Sign files) c) Arnold, seeking to minimise this unbelievable result, said he then conservatively moved the points of measurement down from the summits to the bases of the mountain cones, "below the snowline", and got 39.8 miles.10 39.8 nautical miles or ~46 statute miles is about 8 statute miles too long to fit between the bases of the mountains below the snowline (~6-7000ft in summer; see below). It's actually very nearly the distance between the summits (or other equivalent points). But 39.8 statute miles fits Arnold's description well. d) A somewhat weaker argument is that Arnold himself gave the cruise speed of his own plane as "about 100mph"11 or "105mph".12 (One early newspaper gave the speed of his plane as "about 110 miles an hour"13 but this could have been Arnold's estimate of groundspeed, adding a vector component of a 19kt NW wind; see Section.3 & Appendix 2). The specifications of the CallAir Model-A give the cruise (air)speed as about 100 statute mph. Had Arnold been thinking in nautical miles he would have said, firstly "87", not "100", and of course he would also have said "knots" instead of "mph". 10 Arnold's meaning is that he selected a point low on the south side of Rainier and a mirroring point low on the north side of Adams, an interval "so far on the conservative side that I knew it was incorrect" (ibid., p.14). Clearly the interval which he had actually used for clocking the speed - between two equivalent points on the south sides of both similar cones (see Fig.4) - would be one mountain-width longer, about the same as the interval measured between summits. 11 Arnold, K., "How It All Began" in Fuller, Curtis G., Proceedings of the First International UFO Congress [1977], Warner, 1980, pp. 17-29 12 "I'll never forget Capt Smith chuckling at my airspeed registering only 105mph". Arnold, K. and Ray Palmer, The Coming of the Saucers, Amherst 1952 p.41 13 One newspaper gave Arnold's speed as "about 110 miles an hour" (Pendleton, Oregon, East Oregonian, June 26 1947) 3) Reconstruction of Arnold's flight path in relation to Mt Rainier Forty-eight hours after the sighting Arnold guessed that he had begun his turn and climb towards the sighting point "approximately 25 to 28 miles from Mount Rainier"14 and that his distance from the objects was "between 20 to 25 [statute] miles" (32km - 40km).15 Five years later in 1952 Arnold had narrowed these brackets to a figure of 23 miles on the basis that "I knew where I was and they revealed their true position",16 but this confidence is somewhat belied by 10%-20% error-margins in his contemporaneous accounts, indicating that at the time he was perhaps not quite so certain where he was. Therefore an attempt is in order to reconstruct Arnold's flight path from topographical reference points, known times and distances and aircraft performance specifications. Several factors in this exercise lead to the conclusion that the closest approach would certainly have been nearer the lower than the upper bracket, and probably was somewhat less than 20 miles (<32km). Below is the relevant part of Arnold's earliest detailed written narrative, prepared shortly after July 04 1947, a copy of which was sent to the the Commanding General, Army Air Force, Wright Field, Ohio, 14 days after the sighting on or about July 08: I flew [from Chehalis, Washington] directly toward Mt Rainier after reaching an altitude of about 9,500 feet which is the approximate elevation of the high plateau from which Mt Rainier rises. I had made one sweep of this high plateau to the westward [A on Fig.3], searching all of the various ridges for this marine ship [a missing US Marine transport plane] and flew to the west down and near the ridge side of the canyon where Ashford, Washington, is located [B & C on Fig.3]. Unable to see anything that looked like the lost ship, I made a 360 [sic] degree turn to the right and above the little city of Mineral [D on Fig.3] starting again towards Mt Rainier. I climbed back up to an altitude of approximately 9,200 feet.17 . . . I trimmed out my airplane in the direction of Yakima, Washington, which was almost directly east of my position, and simply sat in my plane observing the sky and the terrain. . . . The sky and air was as clear as crystal. I hadn't flown more than two or three minutes on my course when a bright flash reflected on my airplane [E on Fig.3].18 14 Interview with Kenneth Arnold by journalist Ted Smith, broadcast on KWRC radio, Pendleton, on June 26, 1947. Some background on Ted Smith and KWRC Pendleton can be found at the Western States Museum of Broadcasting: http://www.wsmb.org/Files/WSMB%20Vol%203%20Issue%201.pdf 15 Kenneth Arnold, report to the Commanding General, Wright Field, Dayton Ohio, 12pp typescript c. July 08 1947 (NICAP/CUFOS files). Note this signed and annotated original is not the recopied version preserved in the Project SIGN Incident #17 case file. 16 Arnold, K. and Ray Palmer, The Coming of the Saucers, Amherst 1952 p.12 17 The author is indebted to Canadian pilot and author Don Ledger (emails 12.03.2010 & 13.03.2010) for pointing out that Arnold's altimeter reading may not have been accurate because local temperature and pressure would probably differ from the last pressure setting at Chehalis an hour earlier. Don has known errors up to 800ft over very small distances in this area. On the other hand, sea-level pressure variation on this day was only 4.3mbar between locations well over 200 miles apart on the coast and East of the Cascades and slightly elevated above a atandard atmosphere, suggesting a broad region of high pressure consistent with reports of clear weather and exceptionally smooth flying (see Appendix 2). An 800ft altitude error would correspond to about six times this surface pressure variation (0.76" of mercury or 26mbar). This suggests that orographic uplift or 'mountain wave' conditions would be the most likely cause of any extreme and/or rapid fluctuations of pressure between Chehalis and Mineral, which are only some 30 miles apart. These would not be caused by the nearby Cascade Mountains - because the recorded wind (Seattle) was 300º, blowing from the sea and across the low plains WNW of Mineral - but perhaps by the Olympic Mountain barrier rising more than 100 miles NW of the area. Perhaps it is safe only to say that the altimeter is likely to have been accurate to within ±5%. But this margin would not significantly alter any conclusions here. 18 Kenneth Arnold, report to the Commanding General, Wright Field, Dayton Ohio, 12pp typescript c. July 08 1947 (NICAP/CUFOS files) Fig.2 Looking East from 9,200ft near Mineral, Washington, with the summit of Mt Rainier ~20 miles (32km) distant (GoogleEarth image). There is a back-stop on the possible distance because when Arnold first saw the flashes of the objects approaching from north of Mt Rainier he was flying back east from Mineral, which is itself only about about 22 - 23 miles (35 - 37km) WSW of the peak of Mt Rainier. When he saw the first flash he was already 2 - 3 mins of cruise (3 - 5 miles at 100mph; 5 to 8 km) into this leg of his flight to Yakima, with his plane and the objects on converging paths, so he would have been closer still when, after another minute or so, he saw them pass the southern edge of the snowfields of Mt Rainier and cross his course. In his 1952 book Arnold recollected that he had made his first sighting "while making a turn of 180 degrees over Mineral".19 In 1977 he repeated this, saying "As I was making this turn . . . a tremendous flash appeared in the sky", but added the confusing rider that it was "as I was making this turn and, of course flying directly toward Mt. Rainier, at about 9200 ft elevation"20 which is only consistent if what he really means is that the first sighting occurred not during but after the climbing turn. And this is in fact what he had said explicitly in his original and more detailed July 1947 Air Force letter: He came west at search height down the canyon past Ashford, made a right turn "above the little city of Mineral, starting again towards Mt Rainier" and climbed back to 9200ft, at which altitude he then "trimmed the plane towards Yakima" (to pass south of Mt Rainier) and sat back to admire the view for another "two or three minutes" before he saw the first flashes off to his left, north of Mt Rainier. In order to see what this implies we need to investigate the specifications of Arnold's aircraft. Arnold's CallAir was a specialised, light-weight, mountain plane optimised for performance above about 6,000ft, with a single 125hp Lycoming or Continental engine and big, high-lift wings designed for short take-offs in confined mountain valleys. It was either a late model A-2 or an A-3 and was purchased new from the company in Afton, Wyoming, in January, 1947, registration number NC33355.. It was what was known as a "2-3 place", with a wide bench seat commodious 19 Arnold, K. and Ray Palmer, The Coming of the Saucers, Amherst 1952 p.10. 20 Arnold, K., "How It All Began" in Fuller, Curtis G., Proceedings of the First International UFO Congress [1977], Warner, 1980, pp. 17-29. See: http://www.ufologie.net/htm/arnoldrepiuc.htm for a pilot and passenger (controls and main instrumentation being, as usual, in front of the left seat) but able to accommodate three if necessary. The CallAir was highly regarded by pilots as agile and dependable, unusually smooth to fly, free of the common light-single vice of pulling left due to the prop wash over the tail assembly and so requiring little handling in cruise.21 The exact performance figures are uncertain. As usual published specifications are optimised and actual performance will vary with propellor size, propellor pitch, altitude, fuel and baggage load etc. Initial hopes that the actual aircraft had been located proved unfounded22 so precision is not possible, but it is possible to be confident of approximate figures. Assuming the 125hp engine (in a late model A-2 or an A-3 of this date), the maximum rate of climb of Arnold's CallAir was about 1000 ft/min with a climb ratio approaching 5:1; the nominal cruise speed in level flight at 75% power was a little over 100mph; and top speed was 120mph at maximum power (Table 1).23 Some early CallAirs with the smaller 100hp Lycoming engine are credited with having a higher top speed (150mph) and higher stall, but a much lower climb rate of only 300ft/min24 perhaps indicating also different propellor size and pitch. But the cruise speed is about the same in all variants, a little over 100mph. This figure fits Arnold's own statements (see Section 2.d). Table 1. From Arentz, B., The CallAir, FLYING Magazine, Jan 1950, p.32 21 Arentz, B., The CallAir, FLYING Magazine, Jan 1950, p.32 22 What is claimed to be Arnold's original A-2 is today owned by the Skagit Aero Education Museum at Concrete, Washington. It was used for a re-enactment of the sighting by Discovery Channel in 2002. See: http://skagitaero.com/aircraft/call-air-a-2/ However SAEM has not been responsive to inquiries, possibly because the N-number of Arnold's CallAir (N33355) is in fact FAA registered today as belonging to a CallAir A-3 certified flightworthy in 1960, see http://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?NNumbertxt=33355 which appears to corroborate information from pilot and author Don Ledger (private communication 17.03.2010) to the effect that Arnold's CallAir was sold and crashed in Mexico during the 1950s. According to a note attached to this record of Arnold's number at http://www.airport-data.com/aircraft/N33355.html it was an A-3 with a 6-cylinder Continental 125hp engine, but originally built in 1947 and "rebuilt almost from scratch" by its new owners in Idaho in 1968. 23 Arentz, B., The CallAir, FLYING Magazine, Jan 1950, p.32 24 Kilber, R., 'A Wing, a Prayer and a CallAir' Custom Planes Magazine, August 1999 p.28. http://ronkilber.tripod.com/callair/callair.htm http://en.wikipedia.org/wiki/CallAir_Model_A#Specifications_.28A-2.29 Arnold described his turn and climb over Mineral as "slow and steady", which does not suggest urgency or the wish to consume a lot of fuel; but to be conservative let us assume that Arnold was in a maximum-power climb from having searched the canyon, achieving 1000ft/min in a climb ratio of 5:1, then neglecting winds25 every 1000ft of climb takes him about 1.0 mile on the ground. No early source tells us the altitude to which Arnold had descended in searching the canyon, but a very low altitude in the order of 100 ft or less over the slopes is implied by Arnold's recollection in 197826 which makes sense of his statement in 1977 that he broke off searching along the ridge side of the canyon and came over Mineral at about 2000 ft: As I came out below on this first sweep I passed over the little community of Mineral, Washington, the pine trees there,27 and knew pretty much where I was. I made a turn at probably 2000 ft over Mineral, Washington and started climbing back, slowly but steadily climbing, to gain sufficient altitude to go back on the high plateau again for another pass at this mountain.28 The region around Mineral is at about 1400-1500ft AMSL so if Arnold turned above Mineral at 2000ft AMSL as indicated by altimeter, then he climbed 7200ft during his turn "over Mineral" before levelling off on a heading back to Mt Rainier. Alternatively, if he meant 2000ft AGL judged by Type 1 eyeball then he climbed 5800ft. So this climb would take him a minimum of between 5.5 and 7 minutes, and at ~60mph ground speed he would travel at least 5.5 to 7 miles on the ground before reaching 9200ft. It makes no sense that Arnold would have consumed more than necessary of this distance in continuing directly west from Mineral when his destination lay behind him to the east of Mineral. He tells us that he made "a turn over Mineral",29 "a turn of 180 degrees over Mineral",30 or "a turn to the right and above the little city of Mineral",31 so it is difficult to see how he could possibly have been much further away from Mt Rainier than the town of Mineral by the time he levelled off at the top of this turn. He could in principle have turned in a tight spiral of chandelles directly above Mineral 32 but this power manouver costs fuel and would not answer the description of a "slow, steady" climb beginning after the turn, as clearly implied in Arnold's detailed early report.33 So one 25 Arnold reported that winds were "from the NW most of the way up", which was confirmed by McDonald from the Boeing Field (Seattle) evening radiosonde. Together with surface wind obs at Tacoma and Seattle of 5kt and 10kt respectively the profile suggests mean NW winds in the order of 10kt over the altitude range from surface to 10,000ft (see Appendix 2). The small effect of this mostly cancels out in the groundspeed calculation over 180º of climbing turn. 26 Describing flying the same route in 1948 to film the remains of the crashed Marine C-46 on the glacier, Arnold recalled: ". . . I didn’t go up to the 14,000-foot level and come completely down the canyon as I did in ’47 because the wind was so turbulent that day, and you can get trapped in some of those places… But in order to really search an area very thoroughly, you’ve got to go very slowly, you’ve got to watch out for your wind change, and you usually want to stay at least twenty-five to fifty, maybe seventy-five feet up to as high as a hundred feet up off the mountain. So, that’s the reason I didn’t really fly in to take a movie of the crash because it wasn’t too important and the winds were getting pretty bad up there." Conversation with Kenneth Arnold, Feb 06 1978, Bob Pratt. http://www.ufoevidence.org/documents/doc1998.htm 27 Mineral, distinctively sited on the south shore of Mineral Lake, had been a notable logging and mining town for decades because the area's "unusually heavy untouched timber [pine forest] and mining of many valuable minerals". (http://www.headquarterstavern.com/). 28 Arnold, K., "How It All Began" in Fuller, Curtis G., Proceedings of the First International UFO Congress [1977], Warner, 1980, pp. 17-29. See: http://www.ufologie.net/htm/arnoldrepiuc.htm 29 Ibid. 30 Arnold, K. and Ray Palmer, The Coming of the Saucers, Amherst 1952 p.10 31 Arnold, K., report to the Commanding General, Wright Field, Dayton Ohio, 12pp typescript c. July 08 1947 (NICAP/CUFOS files) 32 The CallAir had a notably small radius of turn suitable for tight manouvering in narrow canyons (Arentz, B., The CallAir, FLYING Magazine, Jan 1950, p.32) 33 Kenneth Arnold, report to the Commanding General, Wright Field, Dayton Ohio, 12pp typescript c. July 08 1947 (NICAP/CUFOS files) would expect Arnold to have been have been a few miles east of Mineral by the time he completed his climb. But since we wish to be conservative let us assume that this right-hand turn and climb of ~7 minutes was actually all executed on the far (western) side of Mineral, so that he completes the turn and climb with the plane levelling off at 9200ft with the nose pointed due East above (or abreast of) the town of Mineral, about 23 miles from the summit of Mt Rainier.34 From this point there is then still a period of "two or three minutes" of uneventful cruise to go (equal to 3 - 5 miles at 100mph35) before the first sighting, placing him conservatively only 18 - 20 miles (29 to 32km) WSW of the summit of Mt Rainier at that time (approx. point E in Fig.3) when the objects were first glimpsed far to the north "coming from [the direction of] Mt Baker". Fig.3. Approximate reconstruction of Arnold's likely course (see also Section 10.iv.b), showing lines of sight. Certain excursions from this course are not shown: Arnold indicates that he did not proceed very directly to Yakima afterwards (H) but spent at least some additional time on the look-out for the crashed C-46 and also took the opportunity to fly the length of a ridge south of Mt Rainier to measure the length of the formation of objects. There is considerable uncertainty about this sequence of events (see Section 7). By the time they were crossing Arnold's course South of Mt Rainier (point X on Fig.3), Arnold's eastward flight had taken him closer by perhaps (still estimating conservatively) a further 1 minute or 1.7 miles (2.7km), to approximately point F on Fig.3. Thus his distance from a 170º object-track 34 Arnold's locating of the turn "over Mineral" seems a more reliable fix than rough dead-reckoning based on time and distance; nevertheless a lazy turn a few miles to the West of Mineral would be plausible according to his early June 26 radio interview: "I came out of the canyon there, it was about 15 minutes [from Rainier] approximately 25 to 28 miles from Mount Rainier, [and] I climbed back up to ninety two hundred feet". A travel of 25 miles in 15 mins = ~100 statute mph (87kt), which is the CallAir's specified cruise speed. "25 to 28 miles from Mount Rainier" would be 3 - 5 miles West of Mineral. http://www.ufologie.net/htm/arnoldrepsmith.htm This would tend to fit our conservative model. 35 This is a conservative ground speed. Nearest winds were generally NW, 19kt from 300º at 10,000ft (App.2), so it would be reasonable to assume an easterly vector component of 10kt, adding perhaps a further ½ mile of travel during 2-3 mins. intersecting the summit of Mt Rainier would be on the low side of our bracketed 18 - 20 miles (29 to 32km).36 But more importantly the objects seen passing low on the West side of Rainier against the snowfield were evidently at least some distance less than the summit of Rainier. This is a further argument that 18 to 20 miles (29 to 32km) must be a maximum distance from the objects. The report that the range to the objects was back-stopped by the slopes of Mt Rainier is obviously fundamental to this conclusion. On its face the report seems unambiguous in this regard, but it has been questioned and the issue is important enough to merit more detailed discussion before we proceed. 36 Assuming a straight object course this is a maximum. The heading azimuth can only be significantly larger than 170º (i.e., rotated westward, not eastward) because of the limiting backstops of Mt Rainier and Mt Adams.