Analysis of Radar and Air-Visual UFO Observations
on 24 October 1968 at Minot AFB,
North Dakota, USA
Timing of the B-52 Approach Trajectory and Setting of the Radarscope Clock
The documentation features three time sources, which can be compared to the calculated times of our reconstruction of the trajectory of the B-52. The time entries in the Transcription of Recorded Conversations (Transcript) were encoded relative to the communications according to the RAPCON approach controller’s clock at Minot AFB. The B-52 radar operator and the B-52 pilot manually set the time of the onboard clocks during the preflight checklist, including the radarscope clock. To be precise, the radarscope “clock” is actually a watch, manufactured by Bulova, which is wound and set prior to each mission.
- Let us call ( COM ) the Transcript TIME, which corresponds to GMT.
- Let us call ( RAD ) the TIME indicated by the B-52 radarscope clock, which should also be synchronized to GMT (a hypothesis we want to verify).
- Let us call (PIL) the TIME indicated by the pilot chronometer, which should correspond to (RAD).
According to the Transcript, the B-52 passed over the TACAN WT fix (initial approach fix) and departed FL 200 at 8:54:00 (COM). At this time, the B-52 was located 35 nm from the Deering TACAN at azimuth 306° true. According to our calculations, the distance traveled by the B-52 to the position where photo 783 was taken is 16.2 nm and would have required 0:03:53 minutes at a speed of 250 kts. Although it is unlikely that the speed of the aircraft remained constant during this period, this time would not vary considerably. We can deduce that the (COM) time at photo 783 is: 8:54:00 (COM) + 0:03:53 = 8:57:53.
In order to determine the elapsed time to the position of the B-52 at photo 783, we have shown that the distance (Dis783) the B-52 traveled away from the WT fix along the trajectory would be equal to 13.7 nm. At a speed of 250 kts, this would have required 03:17 minutes. It is unlikely that the speed of the aircraft remained constant during this period, but the time would not vary too considerably. Therefore, we can deduce that the exact time of photo 783 would be: 8:54:00 + 0:03:17 = 8:57:17 (COM).
Following is the resolved position of the B-52 along the descent trajectory, at the precise time indicated by the clock in the last radarscope (photo783):
- Indication of the radarscope clock in photo 783 = 9:06:51 ( RAD).
- Ground altitude of the B-52 during photo 783 = 6205 feet (35).
- MSL altitude of the B-52 during photo 783 = 7928 feet.
- Deering TACAN position of the B-52 at photo 783 = 18.8 nm / 306° true.
If we compare this to the precise time of the radarscope clock in photo 783, we find a significant discrepancy. This difference is equal to 9:06:51 (RAD) - 8:57:53 = 00:08:58, or 9 minutes. This discrepancy has been established from information in the documents, which suggest that the radarscope clock (RAD) was not set to the same time as the approach controller's clock (COM); the pilot’s chronometer (PIL) should show a similar discrepancy.
There are additional indications in the documents that are consistent with our reconstruction of the B-52 trajectory. At about 08:58 (COM), the radio transmission from the B-52 is interrupted in mid-sentence, which is equivalent to the calculated (COM) time of photo 783 at 8:57:53. Thus, it is apparent that the B-52 loss of radio transmission and the sequence of radar photographs occurred concomitantly.
These speculations are confirmed further when we consider that the approach controller contacts the tower controller, while the communications with the B-52 are interrupted, effectively locating the B-52 along its trajectory at a specific time: “09:00 ct to tw: Tower this is on JAG 31, disregard, he is about 24 miles out… .” According to our calculations, at the beginning of the loss of communications (probably photo 771), the aircraft was exactly 21.37 nm (or 24.6 statute miles) from the Deering TACAN.
According to the Transcript, at 09:01 (COM), communications were very weak on 271.3 Mhz, and at 09:02 the communications are restored. If we ignore the range of the effect of the B-52 radio transmission loss as a result of the close proximity of the UFO, we note that it is precisely during the beginning of the series of radarscope photos that radio communications failed. VHF communications were restored one or two minutes after the UFO departed from the radarscope.
Let us examine now the trajectory of the B-52 following photo 783, taken at 8:57:53. At the calculated (COM) time of photo 783 the B-52 is 18.8 nm from the Deering TACAN. The B-52 continues the descent, executes a “missed approach” to the runway, and at 9:06 (COM) announces “31 going around,” which means that the B-52 left the axis of the runway at 110 degrees and turned left onto the traffic pattern to execute the GCA low approach requested at the beginning of the descent.
According to the approach plates, from time 8:57:53 on photo 783 until 09:06 (COM) the B-52 traveled 18.8 + 2.9 = 21.7 nm, which would require 7 minutes, if photo 783 were taken at 08:58. This corresponds to an average speed of 186 kts, a speed that was confirmed by Col. Werlich in the documents and which is correct for the final approach and traffic pattern speed. The position of the B-52 at 09:06 (COM) is consistent with the speed and distance traveled by the B-52 from its location at photo 783, and further confirms the position of the B-52 at the instant of photo 783. This position is also consistent with our reconstruction of the trajectory of the B-52, and the time entries in the Transcript of Recorded Conversations.
At 09:09 (COM), the copilot of the B-52 pilot reports: ”Steady 335 3200,” indicating that he is stabilized in horizontal flight on the magnetic heading 335 degrees at an altitude of 3200 feet MSL (1500 feet above the ground). This was the standard procedure to follow in 1968 at Minot AFB. The course leads the B-52 to move away from the runway, after a left turn of 335 - 110 = 225°.
Towards 09:10 (COM), the tower orders the B-52 to take the new magnetic course 290 degrees and to maintain altitude at 3200 feet MSL. The B-52 is now turning onto the “downwind” leg in the traffic pattern, parallel to the runway.
Around 09:14 (COM), the controller orders magnetic course 200 degrees, altitude 3200 feet MSL. This vectors the B-52 to the “base leg” of the circuit, which is perpendicular to the axis of the runway.
At 09:15 (COM), the tower orders magnetic course 140 degrees, altitude 3200 feet MSL. The B-52 has therefore turned left by 200 - 140 = 60 degrees. This is referred to as an approach with final dogleg, which brings the aircraft to 30 degrees from the axis of the runway in order to safely avoid excessive course changes at low speed. The B-52 is then vectored to the final approach at 110 degrees, which centers the B-52 on the axis of the runway. At 9:17 the B-52 reaches the final approach fix at a distance of 6.3 nm from the Deering TACAN, to begin its final descent to the runway.
Let us sum up the displacements of the B-52 since FL 200 from the WT fix where it began its descent at 08:54 (COM) until 09:17 (COM).
- Initial descent from 35 to 21.37 nm from the Deering TACAN.
- The series of 14 radar photographs locating the B-52 at 18.8 nm.
- An uninterrupted descent to the Final Approach.
- A missed approach to the runway is accomplished.
- At 09:06 (COM) the B-52 initiates the standard traffic pattern, which will bring it in Final Approach at 09:17 (COM), which is 5.4 nm from the threshold of the runway, or 6.3 nm from the Deering TACAN.
This is consistent with standard procedures and corresponds to the speed of a B-52 on approach to landing at Minot AFB. The (COM) time references are fairly coherent with the B-52 trajectory throughout the first circuit around the traffic pattern. Events during the second and final circuit become more interesting.
Timing of the B-52 Trajectory Until Terminal Landing
It takes 11 minutes for the B-52 to go around at 09:06 (COM) and to arrive at the position of the Final Approach Fix (FAF) beacon at 09:17 (COM). Additional time is required for the final approach and landing. On the approach plates, the length of the final approach and landing segment is 7.6 nm, which means that the B-52 took an additional 2 or 3 minutes at its approach speed to land. The total is 11 + 2 to 3 = 13 to 14 minutes. Therefore, we know the flight times of the various legs of the standard traffic pattern. Let us begin at the time when the B-52 was at the FAF for the first time.
- (ac = B-52 [JAG 31]; ct = controller). All times are from (COM) clock
- 09:04+ ct Cleared for low approach …
- 09:06ac 31 going around
- 09:09ac Steady 335 3200 (crosswind leg)
- 09:10? ct JAG31 turn left heading 290, maintain 3200 downwind leg
- 09:13+ ct JAG31 turn left heading 200, maintain 3200 base leg
- 09:15ct JAG31 turn left heading 140, maintain 3200 dogleg to final
- 09:16ct JAG31 turn left heading 110, maintain 3200
- 09:17ac Final approach.
Consequently, the approximate time durations are:
- Crosswind leg heading 335° = 1 minute
- Downwind leg heading 290° = 3 minutes
- Base leg heading 200° = 1 minute
- Dogleg heading 140° = 2 minute
- Final Approach heading 110° before Final Approach Fix = 1 minute
- FAF to terminal landing = about 3 minutes.
Therefore, the total time is 13 minutes after the previous passage of the FAF, and 11 minutes after overtaking of the runway. However, at 09:21(COM), 4 minutes after the FAF the B-52 calls the controller requesting: “I’d like to get a vector around for an IFR, surveillance approach.” The pilot asks for vectors to be followed for an Instrument Flight Rules (IFR) surveillance approach, which means that the B-52 can go down to minimums, while the heading corrections are issued by the ground controller.
The B-52 pilot also adds that he wants to terminally land at 09:40 (PIL). If we add 11 minutes to 09:21 (COM), we get 09:32 (COM), which leaves a margin of eight minutes for enlarging the traffic pattern in order to fly over the UFO, if we subtract 09:32 (COM) from 09:40 (PIL?) (assuming that these two clocks are synchronous), this eight minute difference therefore seems consistent.
In the Transcript there are no specific time indications between 09:21 (COM) and 09:28 (COM), specifying the final landing of the B-52. Indeed, the B-52 could not have been on final approach at 09:28 (COM) because the successive headings were exactly the same as the ones during the previous traffic pattern, which assumes the same geometry for the final pattern. We know that the normal traffic pattern could not be completed in less than 11 minutes; therefore, the B-52 could not be on final approach at 09:28 (COM). At the very least, this suggests that the final times of the transcription of radio communications are distorted.
The pilot stated, “Like to touch down at [09:]40 past,” and the controller responded “Roger you want a full stop at [09:]40,” which are dissimilar requests since touch down refers to the wheels on the runway, while full stop is terminal with engines shut down. If we examine the satellite image of Minot AFB, we see that the end of the runway is less than a mile from the B-52 parking area. Conceivably, 2 or 3 minutes separate the two procedures. The successive traffic pattern circuits appear to be the same, with the exception of a couple points:
- Pilot’s request for an IFR, surveillance approach
- The downwind leg is completely omitted (290° at 3200 feet)
- The pre-final dogleg branch is a course heading of 115° rather than 110°.
Additionally, the controller validates the pilot’s request, “This will be a vector to the surveillance final approach,” adding, “Lost communications remain the same. Do you wish any portion repeated?” The controller seems to be taking precautionary measures in order to avoid another loss of radio communications. Although B-52 crewmembers recalled the order to overfly the UFO, this specific request is not included in the transcript. It seems to be implied by the request, “JAG 31 (garbled) requests that somebody from your aircraft stop in at baseops after you land.”
The Transcript contains various lacunae, yet the accurate time references are missing for at least 7 minutes. I therefore undertook a reconstruction of the trajectory of the B-52 during this special pattern by going backwards and forward from the times we know precisely. An important indicator in the Transcript is evident in the fact that the arrival at the Final Approach Fix is not made according to the heading of the axis of the runway, but on a course of 115 degrees, thereby shortening the distance to the runway.
We know that professional military pilots work with great accuracy, particularly near a base that has numerous heavy bomber movements. Because of their large, long-range design, these bombers are especially difficult to navigate when approaching the runway at night and during instrument approaches. Therefore, it seems to me that the controller intended to satisfy the request of the pilot by stating, “Roger you want a full stop at 40” (COM). The B-52 had to be at the FAF (at the beginning of final approach) at 09:34 (COM), in order that the touchdown occurs at 09:38 ± 1 minute (COM).
We know that the B-52 exceeded the end of the runway at 09:21 (COM), and the complete time duration of this special circuit had to be equal to 09:34 - 09:21 = 13 minutes. This is two minutes more time than the previous normal pattern (11 minutes). In fact, it is enough to slightly lengthen the downwind leg by 1 minute to get this result (1 minute going out + 1 minute for return = the two minutes of difference from the previous pattern). On the basis of the indicated headings, we can now put this unknown traffic pattern into equations. Following, I shall reconstruct a pattern from the indicated courses in which the complete duration is 13 minutes at the speed of 180 kts. Let us call:
- L1 the length of the leg on the course 335° (Crosswind leg)
- L2 the length of the leg on the course 290° (Downwind leg)
- L3 the length of the leg on the course 200° (Base leg)
- L4 the length of the leg on the course 140° (Dogleg)
- L5 the length of the leg on the course 115° (Final Approach).
There are five turns (made with the standard rate of 180° per minute), the durations of which we will call:
- T1 = duration of the first turn, begun at 09: 21 (COM) from the runway heading (110°) to course 335°, which is the beginning of L1. This is a turn of 225° that lasts 1 minute and 15 seconds.
- T2 = duration of the second turn from course 335° to course 290°, which is the beginning of L2. It is a turn of 45° that lasts 15 seconds.
- T3 = duration of the third turn from course 290° to course 200°, which is the beginning of L3. It is a turn of 90° that lasts 30 seconds.
- T4 = duration of the fourth turn from course 200° to course 140°, which is the beginning of L4. It is a turn of 60° that lasts 20 seconds.
- T5 = duration of the fifth turn from course 140° to course 115°, which is the beginning of L5. This is a turn of 25° that lasts 8 seconds.
Total time of turns = 148 seconds (2 minutes and 28 seconds). It took 10 minutes and 32 seconds to go through the straight leg, which corresponds to 31.6 nm at a speed of 180 kts. Therefore,
- The sum of the length L1 + L2 + L3 + L4 + L5 = 31.6 nm.
In addition, the geometry of the complete trajectory imposes a closed circuit, establishing narrow relations between the lengths of the various branches. We know that the distance between the end of L5 (the end of the runway) and the beginning of turn T1 is 3.6 nm. As a result, according to the trigonometry of the pattern:
0.7 L1 + L2 = 0.866 L4 + L5 + 3.6
L3 + 0.5 L4 = 0.7 L1
L1 + L2 + L3 + L4 + L5 = 31.6 nm
We have only three equations with five unknown variables, and therefore several possible solutions. According to the accounts provided by both pilots, the B-52 overflew the UFO during the 90-degree left turn from the downwind leg to the base leg. Consequently, there must be a non-null base leg (L3). We could extend progressively the length of the pattern by augmenting the length of L2 by only 1 nm per step or less. This task should be done on the airport map to verify that the pattern is correctly closed. However, on the map provided by Col Werlich to Blue Book, there is a rectangle drawn near N-7, in the middle of which is written: “Probable area of aircrew ground sighting.” We may want to determine if the previous relations between distances L1 to L5, with the times indicated in the Transcript, are compatible with a position of the UFO on or near the ground in the middle of the rectangle. The answer is yes, placing the center of the turn in the middle of the rectangle!
This circuit is:
- Compatible with the indicated hours in the Transcript (COM).
- Compatible with the full stop of the B-52 at 9:40 (COM).
- Compatible with the traffic pattern procedure (successive courses) such as it appears twice in the Transcript.
- Compatible with the position of the radar photographs.
The dimensions of this pattern are:
- L1 = 9.31 nm
- L2 = 11.17 nm
- L3 = 2.23 nm
- L4 = 12.29 nm
- L5 = 3.08 nm to the runway threshold; 5.21 nm to the runway end.
The position of the UFO in the center of the rectangle is located 16 nm from the Deering TACAN, on the true azimuth 334° (321° magnetic). This rectangle appears on a map overlay prepared by Col Werlich in 1968, which also includes the trajectory of the B-52 during its descent from the TACAN WT fix to the runway.
The following map (Figure 8) includes only the two points representing the places where the UFO was reported to have landed (points marked “FROM GRID REF,” (AA-43) and “16 nm TACAN 320° approx. landing site”). I added the rectangle by determining its coordinates from Werlich’s overlay map. Note that the B-52 circuit passes exactly by the center of this rectangle.
The approximate landing site 16 nm, 320° TACAN and the center of the rectangle (16 nm 334° TRUE) are both 16 nm from the TACAN transmitter. But the point at 320° is located outside the B-52 pattern, which would be incompatible with several facts, particularly the existence of a base leg. What is curious is that both points are on two azimuths whose difference is 14 degrees, which is practically the local magnetic declination in 1968 (13°). It is possible that whoever drew this map confused magnetic with true courses, since TACAN always points out magnetic courses.
Supplementing the Chronological Facts
On the basis of our previous considerations regarding the B-52 trajectory, we can reconstruct the final chronology during which no specific times are indicated in the transcript with the (COM) times:
- 08:58 — B-52 radar photo 783 (B-52 speed = 250 kts. then is reduced to 180 and 150 kts during approach). B-52 radar clock = 09:06:51.
- 09:04 — Outer Marker and beginning of L5.
- 09:17 — End of first pattern at the outer marker. “Final approach” announced.
- 09:19 — End of runway overflown.
- 09:21 — Beginning of L1.
- 09:24 — Beginning of L2. (09:33 on pilot clock). The pilots observe the UFO ahead of the B-52 at 11.2 nm.
- 09:26 — Beginning of turn towards base leg around the UFO (09:35 on pilot clock). Loss of VHF communications.
- 09:27 — Beginning of L3 (base leg)
- 09:28 — Beginning of L4. VHF communications restored.
- 09:32 — Beginning of L5 (final approach).
- 09:35 — Touchdown of the B-52. (09:44 on pilot clock).
- 09:40 — B-52 full-stop and parked.
Major Partin, the pilot of the B-52, reported that he overflew the UFO at 9:35 (PIL), after having viewed the object for five minutes during the course of the downwind leg. He added that the time indications were “fairly certain” since they were acquired “by clock,” which would imply the onboard pilot chronometer (PIL). The duration of the 11.17 nm flight along L2 at 180 kts corresponds exactly to 3.72 minutes. If we add the duration of the turns, the pilot should have seen the UFO for approximately five minutes.However, if we examine the difference of time: 09:35 (PIL) to 09:26 (COM), we receive a time difference of 9 minutes, which is the same and also ahead in time when compared to our reconstruction of the missing times in the Transcript. It is also obvious that the crew coordinated their chronometers to the GMT hour during the preflight planning. In these conditions, it would be normal to find this difference of the time (PIL) of the UFO overflight indicated by the Major Partin. The hour onboard the B-52, including the radar clock (RAD) and the pilot chronometer (PIL), were both definitely early (by 9 minutes) as compared to the hour of the Transcript (COM), which was in principle recorded with the radio communications.