NTSB Factual Report

HISTORY OF FLIGHT:

On September 19, 2016, at approximately 0824 EDT, an Aruba Airlines Airbus A320-200, registration P4-AAA, flight AG-820, from Miami International Airport (KMIA), Miami, FL (USA), to Queen Beatrix International Airport (AUA), Oranjestad, Aruba (Aruba), powered by two International Aero Engines (IAE) V2527 turbofan engines experienced a separation of the outboard fan cowl from the right-hand engine during takeoff. The flight crew was unaware of any anomalies until a passenger alerted the cabin crew of what he saw and the cabin crew relayed the message to the flight crew. The flight crew leveled off at FL220 to assess the damage to the airplane. The crew was not sure if the panel had detached completely or was not visible from inside the airplane. All systems appeared normal in the cockpit but as a precaution the crew elected to return to Miami. The flight had an uneventful landing on runway 09 at KMIA about 40 minutes after departure. The incident flight was 14 Code of Federal Regulations (CFR) Part 129 Foreign Passenger Air Carrier from Miami to Aruba. There were no injuries. The aircraft sustained damage to the engine, engine pylon, right main landing gear, right main landing gear door and right fuselage.

The night prior to the incident the airplane was in maintenance where mechanics were completing a routine weekly check. Part of the weekly check was to open the fan cowl doors to inspect the IDG. Following the maintenance check, the cowl doors were closed and latched. Because the gate area where the maintenance was being performed was dark, the mechanic who completed the work used a flashlight to verify the latches were flush and made sure he heard a click. A second mechanic who was assisting, also verified that the latches were flush but did not use a flashlight; he stated in a post-incident interview that he could see they were flush. The task was then signed off in the logbook as complete but did not specify that the cowls had been opened and closed. The morning of the incident, about 0430, the supervisor in charge of maintenance for Aruba Airlines performed a walkaround (although not required) using a flashlight and did not notice anything unusual about the cowl. According to the Aruba Airlines A318/A319/A320/A321 Flight Crew Operating Manual, section "Procedures – Normal – Standard Operating Procedures – Exterior Walkaround," the fan cowl doors were to be checked that they were "closed/latched." The first officer conducted an exterior walkaround prior to departure and did not notice any abnormalities. He stated that to check the cowl he bent down and checked that it was flush and latched.

FAN COWL DAMAGE/MATERIALS EXAMINATION:

Examination of the inboard (left side) and outboard (right side) halves of the No. 2 engine fan cowl was conducted. The cowls were of a composite construction consisting of aluminum honeycomb core and carbon fiber composite skins adhesively bonded to the inner and outer faces of the core. The fan cowls were held together by four latch/catch mechanisms on the structure.

Visual inspection of the outboard No. 2 engine cowl half revealed fractures and delamination of the honeycomb core, outer skin and inner skin. The fracture and delamination patterns were used to reconstruct the cowl where possible and to determine its fracture sequence. The patterns were consistent with the initial fracture occurring in the bottom and aft portion of the cowl and were also consistent with the two aft latches not being properly latched.

Visual examination of the inboard No.2 engine cowl revealed cracks in the outer skin at the aft root end of a chine attached to the cowl approximately one-third of the way from the top. The latches and keepers were numbered 1 through 4 starting at the forward end of the cowl. The keepers were examined for indications of wear or deformation but no apparent indication of either were found. All the keepers exhibited some play when moved by hand. There were alignment pins on the left side of the cowl that mated with guide holes on the right side. All the pins were present and there were no apparent signs of damage.

More detailed findings of the No. 2 engine fan cowl and latches can be found in the NTSB Materials Laboratory Factual Report No. 17-002.

ADDITIONAL INFORMATION:

Exemplar Airplane Observation:

Following the incident, the investigative team observed the opening and closing of the #2 engine fan cowl on an exemplar airplane at the Miami maintenance facility to understand the procedure. There were no issues identified. In addition, the team attempted to replicate a false or incorrect latching of the cowl but was unsuccessful.

Interview Summary:

Interview statements were taken from maintenance personnel that had contact with the incident airplane prior to its departure from MIA and the Aruba Airlines Director of Maintenance. Additionally, the investigative team interviewed the Aruba Airlines flight crew that flew the incident airplane.

Details of the interviews can be seen in Aruba Airlines Interview Field Notes.

Manufacturer and Regulatory Actions:

In March 2016, EASA released Airworthiness Directive (AD) 2016-0053 to improve the latch and keeper assemblies on Fan Cowl Doors for Airbus A319/A320/A321 airplanes. At the time of the incident Aruba Airlines was tracking and scheduling the modification within the requirements of the EASA AD.

Fan Cowl Door (FCD) losses during take-off were reported on airplanes equipped with IAE V2500 engines. Prompted by these occurrences, DGAC France issued AD 2000-444-156(B), mandating FCD latch improvements. This AD was later superseded by AD 2001-381(B), requiring installation of additional fan cowl latch improvement by installing a hold open device.

Since that AD was issued, further FCD in flight losses were experienced in service. Investigations confirmed that in all cases, the fan cowls were opened prior to the flight and were not correctly re-secured. During the pre-flight inspection, it was then not detected that the FCD were not properly latched.

Prompted by these recent events, new FCD front latch and keeper assembly were developed, having a specific key necessary to un-latch the FCD. This key cannot be removed unless the FCD front latch is safely closed. The key, after removal, must be stowed in the flight deck at a specific location, as instructed in the applicable Aircraft Maintenance Manual. Applicable Flight Crew Operating Manual has been amended accordingly. After modification, the FCD is identified with a different Part Number (P/N).

For the reasons described above, this AD retains the requirements of DGAC AD 2001-381(B), which is superseded, and requires modification and re-identification of FCD.

The FAA has since released AD 2017-13-10 effective August 3, 2017 to address the same issue as EASA AD2016-0053.

Operator Action:

After the incident, Aruba Airlines took the following actions to alleviate further Fan Cowl Door losses:

1. Aruba Airlines embodied a modification by Goodrich Service Bulletin V2500-NAC-71-0325 to alert maintenance and flight crew personnel that fan cowl doors are open.

2. Maintenance personnel ensures that an entry is made in the aircraft log to notify flight crews that the fan cowl doors were opened and closed to perform maintenance

3. Flight crews are required to perform a close inspection of the latches when they see the log book entry and sign their compliance on the log book.

NTSB Probable Cause

the incorrect latching of the #2 Engine Fan Cowl following a routine maintenance check that resulted in separation of the cowl during takeoff.