1980s Boom Boxes and Ice Cubes

The Evolution of the Khreesat Bomb, part two: 1985-88
May 31 2010

Audition, Performance, Recycling
Part one covered the early years of Marwan Khreesat’s bomb-making career in the early 1970s. After reportedly leaving Jibril’s PFLP-GC group in 1973, Khreesat remained quiet for twelve years. Then in 1985 he was reactivated by Jibril, and summoned to Syria to show his old altimeter-based skills with current technology.

Khreesat bought five Toshiba BomBeat 453 units, which have their own little story, but for our purposes they were housing only, and good sized. It’s the timers and altimeters – only four of each - that mattered to Khreesat, and he selected these himself. The pricey detonators, tens of thousands of dollars apiece, were presumably provided. It was enough to re-create his fear-inducing 1970s innovation; he described the end results to FBI special agent Edward Marshman in November 1989:
“Of the five, two were almost ready to go; they only needed to have the pins pulled to arm them. One had only explosives inside with no altimeter or timer. The other two needed two wires to be connected. After Khreesat built these devices, they were shown to Ahmed Jibril, who approved them. Khreesat then disassembled the devices, and the components were taken back to the PFLP-GC office.”
Just when Khreesat started working for Jordanian intelligence is not clear, but when he was summoned again to Neuss in mid 1988, Khreesat came with instructions from his GID bosses in Amman. The people who in turn met with friends at the CIA, MI6, etc. told him to only build fake bombs while working undercover within the PFLP-GC. But things didn’t work out so smoothly – by Khreesat’s story, the terrorists gave him something more concrete than these instructions.

By Abu Elias he was given a sense that he’d be caught making fake bombs, and from cell leader Hafez Dalkamouni he was given his old materials from 1985. The timers and altimeters were the same, and the five detonators were probably also the same. He was also given one of his five BomBeat453s to re-wire, so one IED was of completely recycled materials.

Working between October 22 and 25, Khreesat thus made four Ialtimeter bombs total in Neuss: this 453 unit, two hidden in Ultrasound radios, and one inside a Sanyo computer monitor. All three of these housings were bought in two second-hand shops in Dusseldorf on October 18, says Khreesat. [p16] The rigged 453 was seized on October 26 in the Autumn Leaves raid, when Khreesat and Dalkamouni were arrested. The other three IEDs were only found months later in 1989. Only the “fifth device,” which Khreesat barely touched (he says) is unaccounted for. First we’ll look at the specs of Khrresat’s four bombs, element-by-element, and then briefly at what can be gleaned about the other one.

In addition to the BomBeat radio, monitor, Ultrasound tuners, timers, and altimeters brought to Khreesat on October 22, my portion of Marshman’s report makes no mention of “detonators.” It does however say “Dalkamoni also brought in four blasting caps that were electrical. [p17] I’m not explosives expert enough to know if that means detonators. All I know is they’re the expensive part of the bomb, and the part Khreesat seems less interested in.

These were provided to Khreesat in neuss. He mentions in his report
Four altimeters which were made in Japan. [p 17]
Marshman’s report specified “the altimeters are the same ones he had in 1985,” and Khreesat “does not know how, when, or by whom these altimeters were smuggled into Germany.” [p 32] He does however note that Dalkamouni was the last stop, handling all Khreesat’s supply needs.

I’ve seen nothing to differentiate the altimeters one from another, and at the risk of error will consider them to all work the same. All I have at the moment to show how they were set is from David Leppard’s On the Trail of Terror. The altimeter from the 453 was tested by the BKA’s Dr. Rainer Gobel in a vacuum chamber. “The circuit would close at a pressure between 940 and 950 milibars - equivalent to an altitude of about 2,400 feet.” [p 11-12] It’s tentative, and Leppard is sometimes wrong, but I can work with this for now.

Ice-Cube Timers
The timers are of interest here, and somewhat more complex. The units themselves were basic – a simple electrical capacitor encased in clear plastic resin, its appearance led to the nickname “ice cube timer”. The timer’s built size determines its resistance to electrical charge and thus the time until it “discharges.” Precise details of that process aside, the time delay is unchangeable but reliable.

These Khreesat picked up himself, as he told agent Marshman. “The timers were made by the Fatah group in Damascus. He first saw these timers at the PFLP-GC camp in Syria and four of them were good, so he took them to use.” [p32] Like the altimeters, they came back to him iin Germany but he doesn’t know how. Where it gets complex is when Khreesat explains how the times vary one unit to the next as far as time delay:

One of the timers was a half-hour timer, one was for three-quarters of an hour, and one was for one hour. Khreesat does not recall what time the fourth timer was set for. None of the timers were for more than one hour. […] Of the four timers he used in the IEDs in Germany, he is not sure of the exact times each one was set for, or which device which timer was put into.
It’s possible to tackle the question of “which device which timer was put into,” but first we must address another issue. Just from the seized BomBeat 453’s timer we have a range, not a set time. Again, David Leppard cites Dr. Gobel’s findings: "The time delay of the electronic component fluctuates over a wide margin since the structure of the circuit is relatively simple. Time delays between 35 and 45 minutes were measured." [p 11-12]

This variation of a supposedly set-in-stone delay might be explained by Khreesat, again via Marshman:
"Khreesat advised that the times are not exact and the time changes depending upon how long the timers have been tested after last being used. They usually reset to zero after a day. He used to test the timers three times in a row before installing the timer in a device. He found that in each test the time decreased. When this happened, he put the timers aside, and the next day when he tested them, they would run for the same time as when he had first started them."
Time delay then varies, with a starting baseline (long time) and shortening with repeated tests carried out too soon. Unless someone was testing it in the field just before use, the long time is what would elapse before detonation.

Timer/Housing Reconciliation
Therefore if Göbel found a range35-45 min for one timer, and Khreesat’s roster can be trusted, that’s the 45 minute unit. That was in the seized BomBeat, leaving for the other three a 30 minute one, a 60 minute, and another he can’t remember, but one hour at most.

The Sanyo monitor was seized intact and just as available for study, but its results are less clear. Dr. Gobel’s notes were read back in part at the Camp Zeist trial, and he include this on the Sanyo's ice cube: “Calculated on the basis of the values of the built-in components, the delay time is put at between 30 and 35 minutes.” [Zeist transcripts p 8769] That’s not a range of test results, but a range of estimates based on, it seems, looking at the circuit. If Khreesat is right, this would most likely be the 30 minute unit.

The two Ultrasound radios were not read as clearly – one defied a top BK explosives expert (Sonntag) and blew him to bits, while nearly killing an assistant. Perhaps some clues from that chain of events could tell us if this is the 60 minute timer or the mystery one. The other Ultrasound was purposefully destroyed, for safety and psychological reasons. But one of the two Ultrasounds (it’s unclear which) did yield enough of its timer for Gobel to note:
“[T]he accompanying capacitor is of the same value as in 1 [BomBeat] and 2 [monitor], but has however, jumped out of circuit. […] it can be assumed from the remains of the circuit that the time delay was in the same region as 1 and 2." [Leppard p 144]

To fit with the above, that’s a possible 30 or 45 minute timer, which are both represented by Gobel’s units 1 and 2. This out-of-circuit timer would be the one Khreesat didn’t remember, likely a duplicate of either the 30 or 45. The other Ultrasound then contained the 60 minute timer, if this should all tie up so neatly (don’t count on it).

The Fifth Device
All of the ahe above is fairly academic for understanding the Lockerbie bombing. As noted, all four of these units were intercepted by police, three of them without fatalities. The fifth mystery bomb is the only suspect here for that atrocity, and this bomb was apparently built by Abu Elias rather than by Khrresat. But his work is said to have informed Abu Elias.

Khreesat does give some details of this unit, which help very little in understanding it. He mentions an altimeter, partly visible under the cassette bay, no mention of timer, but parts of the circuit board and transformer were removed, and some modifications concealed under little cardboard boxes. Khreesat was unable to study it closer, as Dalkamouni stood over him the whole time he soldered two simple wires. This bomb has never been tested in a laboratory setting to determine its settings.

If used on Flight 103, however, the results can be observed from what happened on that December night. If we presume the same altimeter setting, which I did earlier but now seems unjustified, it would start the ice cube charging at about 2400 feet altitude. This low level was reached about two minutes after leaving the ground, according to the AAIB report’s altitude profile (see Thirty-Eight Minutes).

The bomb detonated 36 minutes after that point, so if we also presume a Khreesat-style ice cube timer, and presuming this hadn’t been tested before deployment, 36 or perhaps 35 minutes would be its baseline time. It doesn’t even have to fit Khreesat’s four from the Fatah factory, in their neat quarter-hour time units. Perhaps there was no timer, just an altimeter set to 31,000 feet. But whatever exactly was going on inside it, it is apparently modeled after Khreesat’s 1980s work, and might then be expected to behave about like one of his bombs. And of course whatever blew up PA103 behaved in just that way.


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