Ryan International Airlines Airbus Industrie A320-233 incident

The flight departed runway 27R, and immediately after takeoff, a passenger reported seeing a "cover" come off the No. 1 engine. The captain felt the airplane "shutter," declared an emergency, and returned the airplane to the airport and landed without further incident. Examination of the airplane revealed both sides of the No. 1 engine fan cowl were separated. The inboard fan cowl door was found approximately 7.5 nautical miles west southwest of the airport, and the outboard fan cowl door was found beside the runway. Examination of the latching mechanisms on each cowl door revealed no evidence of failure or mechanical malfunction. A mechanic stated he opened the fan cowl for the No. 1 engine prior to the flight, and he could not recall if the cowl doors were fully latched. A review of data provided by the Transportation Safety Board (TSB) of Canada revealed that, between 1991 and September 2000, there were ten similar cowl door separation events documented worldwide, and each involved the cowl doors having been opened prior to the flight. Examination of the incident airplane revealed it was equipped with the modifications outlined in Airworthiness Directive (AD) 2003-18-06 amendment 39-13297, which mandates the installation of a hold-open device for the cowl doors, as well as a modification of the latch handles to ensure that unfastened latch handles will hang down. A review of the operator's A320/321 preflight checklist revealed it included for each engine, "Check the fan cowl doors." During post-incident examination, a visual walk-around was performed with the undamaged No. 2 engine cowl in various unlatched configurations. Examination revealed unlatched cowl doors can appear closed flush when the hold-open device is overridden in preparation for latching, and unfastened latches that hang down may be obscured from view by the shape of the fan cowl. In response to this incident, Airbus Industrie issued an Operator's Information Telex to "A319/A320/A321 V2500 operators." The telex recommended that, in addition to mandatory compliance with AD 2003-18-06, operators consider the following: "... strictly adhere to AMM Task 71-13-00 for proper latching and closing of fan cowl doors after each maintenance action requiring cowl opening. ... It is essential that a flight crew member visually inspects the fan cowl doors prior to each flight to ensure that they are closed and latched."

Verbatim NTSB analysis and probable cause from the NTSB dataset