For some time, incidents have been reported of passenger doors opening shortly after take-off. In each case, an improperly locked door was left unobserved by cabin crews, while flight crews probably overlooked the DOOR UNLOCKED warning light during their pre-flight checks.
In 1988 Fokker issued service Bulletin F28/52-101 to improve the passengers door lock warning system. All the incidents occurred on aircraft on which this particular improvement had not been incorporated. Although the existing door lock warning system should be adequate, a recent incident, in which a door opened at 21,000 feet, prompted another review of the system. Fokker considers that all occurrences could have been avoided if this modification had been accomplished.
The RLD and CAA concur with this view and since the unsafe condition described may exist or develop on other aircraft of the same type design, this Airworthiness Directive requires the modification of the passenger door lock warning system.
This amendment is issued following the amendment of the RLD Airworthiness Directive and changes the applicability to aircraft in a post SB F28/52-72 configuration.