Since the advent of terrain avoidance and warning systems (TAWS) installations in jets starting in the 1970s, instances of controlled flight into terrain (CFIT) accidents worldwide by this segment have declined significantly, but TAWS aural alerts can become a nuisance or a distraction to pilots when flying at altitudes below the alerting threshold. This often results in pilots deciding to mute these alerts, which the FAA cautions against doing in newly released Information for Operators (InFo) 23003.
“Inhibiting [TAWS] systems and ignoring warnings, combined with deteriorating weather conditions leading to loss of visual surface reference and situational awareness, has been found to be the cause of some CFIT accidents,” the FAA says in the communication.
“Multiple CFIT accidents have occurred when pilots, who are flying VFR at low altitudes are presented with risks associated with rapid changes in weather, resulting in loss of situational awareness,” the notice says. “Additionally, lack of familiarity with the approach or misreading the approach plate are common causal factors, particularly where the approach features step downs in altitude from the initial approach fix to the final approach fix.”
Between 2017 and 2022, the Flight Safety Foundation’s Aviation Safety Network reported 91 jet airliner accidents, of which 20 were classified as CFIT. In the same six-year period, ASN data showed that only four of 192 business jet accidents involved CFIT.