Sir, In his Q&A column “Difficulty of detection is main worry” (FT, November 1) James Blitz writes that “US and British security chiefs say they are confident the bombs were designed to blow up the aircraft on which they were travelling”. However, there are two reasons to doubt this finding. First, the bombs supposedly would be triggered by mobile phone calls, as Mr Blitz writes. However, mobile connection with flying aircraft is very unreliable; as the terrorists will obviously know. This vulnerability in the terrorist plan would not be relevant if it was their intention to blow up the aircraft shortly after takeoff and – in other words – still within range of the airport of departure; obviously this was not the plan. The addresses of the two packages (synagogues in Chicago) are the second reason to expect that the bombs were not supposed to be triggered in flight. If in-flight detonation was the intention, the packages would have had other types of addresses, less vulnerable to interception. The scenario I consider more realistic is that it was the intention of the terrorists to detonate both packages today, November 2, in Chicago, President Barack Obama’s home town. That would have had disproportionate impact on the US, again showing its vulnerability.
Amsterdam, The Netherlands