'The Board concluded that electromagnetic interference was not a factor in the accident.'
If one reads the associated reports, from Boscombe and Farnborough, it is clear neither establishment were informed as to what portable electronic devices were carried by passengers. If you do not know that baseline, how can you validate it and then verify the results of any analysis or testing?
Hence, their reports are couched in terms that discuss “standard” equipment. If anyone was to have “non-standard” equipment, it would be those passengers. Even so, the Farnborough report states, for example, that transmitters in the aircraft could “
easily” have generated the power levels required to interfere with GPS.
Indeed, MoD now claims they do not know what devices were recovered from the wreckage, despite the BoI confirming devices were recovered and a general requirement on MoD to retain, indefinitely, such information.
One should ask why both Boscombe and Farnborough had to be tasked to conduct this testing in late 1994, when it should have been completed satisfactorily before the CA Release Recommendations were signed by Boscombe. Nowhere do the BoI or DRA refer to prior testing.
The answer lies in this simple fact - Boscombe declined to sign formal CAR recommendations precisely because the aircraft testing regime was not complete. Why waste valuable REG (RF Environment Generator) time testing FADEC when the device hasn’t been validated or verified? You don’t. By definition, as the FADEC was not validated or verified on 2nd June 1994, nor was the EMC performance. I can just hear DRA’s reaction to this BoI tasking – “Now they want the thing tested, after the event and a year after we told them the thing wasn’t airworthy”. The bottom line is that the reports compiled for the BoI are very limited and, in my opinion, do not warrant the firm statement 'The Board concluded that electromagnetic interference was not a factor in the accident.'
Finally, the glaring omission is any investigation into the power interrupts reported by Boscombe and test pilots, and the effect any associated surges or spikes may have had on, for example, the AFCS. One must always recall the statement of 28th February 1994 that modifications (plural) are in hand to resolve numerous in-flight UFCMs. Nowhere else are these supposed modifications mentioned before the crash and at no time does the BoI indicate they have asked any relevant questions. For example, what caused the “
Yaw kicks” and “
very sharp uncommanded inputs to the yaw axis which result in rapid 3-4 degree change in aircraft heading in both hover and in forward flight, when the aircraft is subject to high levels of vibration”. This just happens to be the evidence Sqn Ldr Burke was prevented from giving.
So many questions. So much doubt.