Just a thought, were LVP's and ILS Protection in force? given the crash site it is possible there may have been interference with the ILS signals. Security radios and blocking devices may have been active at the time, given the " content" of the aircraft. Apparently when the PMs convoy passed LHR just before the BA 777 crash, the ILS bent like a banana! Ok we accept it was not a factor there.. but food for thought??