This is the Sound Report from MEBO AG, as received (25/05 with no further translation), dated May 21, 2000.
All spelling errors etc. belong to the original author, not me. Active URL-linkings on report are mine.
Hardcopies avilable on request "The first MEBO "explosion-research" report is available HERE
MEBO SOUND REPORT FROM PANAM-103
NO DETONATION SOUND ON THE (CAM)-RECORDER !
Zurich, 21 May, 2000
sound3
This MEBO-report fully supports the recently completed-/published MEBO "explosion-research"-report!
Cockpit voice recorder
The Boeing 747 aircraft was equipped with a 30-minute duration 4-track Fairchild model A 100 CVR, and a Fairchild Model A 152 cockpit-area microphone (CAM). One microphone with omni-directional characteristic system was installed on flight-deck level in the cockpit. This area-microphone is ideally fastened and cushioned in order to avoid the collection of vibration-sounds from the aircraft itself and the engines. The microphone is prepared to register all sounds like i.e. the opening and closing of the cockpit-door, conversation between crew-members, etc. to then be registered by the CAM-recorder channel no. 4!
For the conclusive research-result and decision that no explosion sound was registered from the cockpit location, we only need to concentrate on the channel 4-area microphone!
The channel allocation was as follows:
Channel 1 Flight Engineer's RTF
Channel 2 Co-Pilot's RTF
Channel 3 Pilot's RTF
Channel 4 Cockpit Area Microphone
The erase facility within the CVR was not functioning satisfactorily and low level communication from earlier recordings were audible on the RTF channels. The CAM channel was particularly noisy;- probably due to the combination of the inherently noisy flight-deck of the B747 100 in the climb, and distortion from the incomplete erasure of the previous recordings. On two occasions the crew had difficulty understanding ATC, possibly indicating high flight-deck noise levels. There was a low frequency sound present at irregular intervals on the CAM track;- but the source of this sound could not be identified and could have been of either accoustic or electric origin.
The CVR tape was listened to for its full duration and there was no indication of anything abnormal with the aircraft or unusual crew behaviour. The tape record ended at 19.02.50 hours, with a sudden loud sound (not a detonation-bang) on the CAM channel followed almost immediately by the cessation of recording whilst the crew were copying their transatlantic clearance from Shanwick ATC.
AIRCRAFT ACCIDENT REPORT 2/90
On page 56 from the official AAIB-report, under "conclusion" (a) findings, we locate the summary under (vii):
the analysis of the flight recorder, using currently accepted techniques, did not reveal positive evidence of an explosive event!
See: audio-recording diagrams in the AAIB-report 2/90, Figures C-2, C-3, C-4, C-7, C-8 and C-10.
Why is there no recording of an explosion-/detonation on the CAM-recording tape, channel 4 ?
MEBO can present the only reasonable explanation for this situation:
A sufficiently powered, modulated sound-wave travels from its point of generation at 330m per second (330/sec), in dead air. (flash---thunder)
If i.e. an explosive detonation produce a volume of sound measured at 150dB (formula for the dissipation of the sound sound-volume per metre of travel-time 150dB:xyx);- this will result in a remaining volume of sound of xxxdB pressure at 330m. Within one milli-second the sound wave therefore expands at (330:60) 5.5 m.
The directly measured distance in the 747/PA-103-aircraft, from the centre of the explosion;- at station position 700, to the cockpit area-microphone is about 12 metres. The detour of the sound-pressure via the lateral air-ducts is determined to be negligeable, for this calculation-purpose the sound wave thus needs about two milli-seconds from position 700 to the area-microphone.
The detonation of the explosive device that had been placed directly onto the inner wall of the freight compartment fuselage at position 700, lasted only fractions of a milli-second to rip the 55x45cm large hole into the fuselage, whereby the principal sound of detonation- bang (positive modulated pressure-wave) evaporated from the inside of the freight-compartment to the outside due to the immense difference in pressure (overpressure).
The negative pressure wave that was being produced at the same time was allegedly positioned against container AVE 4041 PA, where it was:
1) solidly slowed down by the simutaneously produced difference in pressure from the inside to the outside of the aircraft.
2) additionally met by the fiberglass panel on position 700, where the remaining negative shock-wave was once more weakened before allegedly reaching the slanted side and floor of the container AVE 4041 PA.
At this time we must point to the reconstruction of the container-floor inside the freight compartment in AAIB-2/90 report, figure F11. This illustration has most likely been photographed from an angle to give the impression as if the indicated center of explosion (crossing: stringer 39L and frame 700), suggesting that the explosion originated from within the container.
There is an alternative explanation: the reconstruction of the container is wrong! In this case the container-floor would show to be positioned too high, near stringer 39L! In reality this container was placed floor-level onto position: stringer no.40, roughly 25 cm lower than shown in the re-contruction sheme! (see: figure F-13 of the AAIB-2/90-report). This tends to additionally feed the suspicion that such an error in the official forensic report was published to support the pre-conceived explosion-theory!
The MEBO-researched results decidedly demonstrate that the sound of the alleged explosion (bang-sound) could impossibly reach the cockpit due from the outside to a number of physical reasons, like i.e. the full travel-speed of the aircraft at 11'000m having reached 800km/per hour. At this speed to the aircraft, the sound-wave would have to travel 300m/sec. to reach the 12m-distant cockpit-microphone. No logical chance whatsoever!
CONCLUSION:
It does not seem to be the case that the channel 4 CAM-microphone was inadequately collecting-/or registering the intended sounds of a possible explosion.
With the alleged explosive charge having been placed directly onto the skin of the fuselage there was no chance at all for the explosion-sound (detonating-bang) to reach said cockpit microphone.
Please note: The AAIB-2/90-report declares that a radio-bomb (improvised explosive device) had detonated inside a Samsonite suitcase and this again inside container AVE 4041PA (figure F-13 AAIb-2/90 report).
Had the explosion however originatet from inside the container AVE 4041PA, then the modulated positive and negative pressure-wave combination that would have been present for fractions of a milli-second in the then still undamaged freight-/ and passenger-compartment, would have expanded sufficiently to prevent the fuselage-skin to be ripped open! The detonation-sound (sound-bang) would then have reached the omni-directional cockpit microphone and the explosion-sound would also have been registered by the CAM-recorder, recalling that there was an alleged distance from the IED inside the container to the fuselage-skin (pos.700/St.39L) of min 25"/63.5 cm; (see: figure F-13, AAIB-2/90-report)!
This discovery additionally supports the MEBO-report: "No Bomb in Container AVE 4041PA". The explosive device must have been placed directly onto the inside of the fuselage-skin, precisely at the crossing of stringer 39L and frame 700. It is virtually impossible to so place a Samsonite suitcase into the small space available between the fuselage-skin and the fibreglass-lining (a space to small even for an alleged Toshiba-radio). MEBO speculates, that a simple and small chemical 2-hour military timer-/detonator has been used to ignite the explosives! Had flight Pan Am-103 started the journey on time (the flight was actually 1/2 hour late), then the aircraft would have been destroyed over some of the deepest ocean-wathers off the coast of Scottland;- as was most likly planned by the actual perpetrators of thin crime!
Another MEBO-observation (in many ways also belonging to the first MEBO-report "There was no explosion...") focuses on the forensic picture (fig. F-10 of the AAIB 3/90-report; forward face of container AVN 7511PA, pos.21L, Figure F-1, view looking aft) where we recognize that the fibreglass-container, which was allegedly placed next to the alleged bomb-container AVE 4041PA on location 14L, shows relatively small damages from the alleged explosion! MEBO-observation of most of said fractures on the fibreglass walls suggest that these damages do not stem from the explosion, but rather from shattering on the floor.
The alleged explosion-wave from inside the container AVE 4041PA, (see figure F13) is said to have travelled through the easing of the alleged Toshiba radio-recorder, the Malta-originated clothing that was allegedly wrapped around the radio, the fibreglass Samsonite suitcase-siding, the metall-wall of the container AVE 4041PA and the the fibreglass seperator-panel that covers the stringer and frames:- to then rip said hole into the aircraft fuselage! And this all over a total distance of 25"/=63.5 cm from the centre of the explosion to the skin of the fuselage!
On the other hand can we measure a distance of about 12"/=30cm from the alleged centre of explosion to the fibreglass-container AVN 7511PA, pos.21L. Even non-experts can quickly discover and compare that the officially stated data are contradictory to the damages shown on the fibreglass-siding of container AVN 7511PA! Therefore it is the clear MEBO-conclusion that the alleged explosion did not originate from within container AVE 4041PA: but from an explosivedevice that was directly placed against the fuselage-skin of the aircraft!!!