B767 Fire and Uncommanded Evacuation After Lockwire Omitted (Dynamic B737-200 N251MY at Fort Lauderdale, FL)

On 29 October 2015 Dynamic International Airways Boeing 767-200ER N251MY, powered by Pratt & Whitney JT9D-7R4E4 engines, experienced a fuel leak and fire on the ground at the Fort Lauderdale-Hollywood International Airport, Florida (FLL). One of the 100 passengers received serious injuries from jet blast, 21 minor injuries and the aircraft sustained substantial damage.

Fire Damage to Dynamic Boeing 737-269ER N251MY (Credit: NTSB)

Fire Damage to Dynamic Boeing 737-269ER N251MY (Credit: NTSB)

The Accident

The US National Transportation Safety Board (NTSB) explain in their safety investigation report (issued 8 June 2020):

A significant fuel leak and subsequent fire occurred in the left engine strut and nacelle during taxi…

The flight crew promptly shut down the left engine using the fire handle, and requested fire equipment.

The “A” flight attendant activated the emergency signaling system…to notify the flight deck and other crewmembers of an emergency. The chime was audible in the CVR recording, but the flight crew did not respond via interphone. There was no indication on the CVR of an evacuation checklist or communication between the cabin and flight deck.

As the airplane stopped on the taxiway, passengers saw the fire and insisted that the cabin crew initiate an evacuation. One passenger opened an overwing exit on his own, and the slide did not deploy. The cabin crew initiated the evacuation without coordination with the flight crew.

After the evacuation had already begun, the flight crew advised over the PA to evacuate out the right side of the airplane.

Dynamic Boeing 737-269ER N251MY On Runway After Evacuation (Credit: via NTSB)

Dynamic Boeing 737-269ER N251MY On Runway After Evacuation (Credit: via NTSB)

The flight crew did not immediately shut down the right engine and an evacuating passenger ran behind the engine [about 11 seconds after the aircraft was stopped] and was blown to the pavement resulting in serious injuries.  The lack of coordination between the flight crew and cabin crew resulted in the evacuation initiating while the right engine was still running.

About 35 seconds later, the number 2 engine was shut down.  About 54 seconds after the airplane stopped, an airport authority official arrived, and repositioned the 2R slide. About one minute later, airport firefighting vehicles arrived and began extinguishing the fire.

https://youtu.be/9K3HDfhgdXo

Left Hand JT-9D Engine Damage, Dynamic Boeing 737-269ER N251MY (Credit: NTSB)

Left Hand JT-9D Engine Damage, Dynamic Boeing 737-269ER N251MY (Credit: NTSB)

Wing/Body Fairing Fire Damage to Dynamic Boeing 737-269ER N251MY (Credit: NTSB)

Wing/Body Fairing Fire Damage to Dynamic Boeing 737-269ER N251MY (Credit: NTSB)

The Safety Investigation

During a visual examination of the left engine and strut, a fuel coupling assembly was found separated with the coupling body pushed aft on a main fuel supply line.

Fuel Coupling Being Examined In Situ, Dynamic Boeing 737-269ER N251MY (Credit: NTSB)

Fuel Coupling Being Examined In Situ, Dynamic Boeing 737-269ER N251MY (Credit: NTSB)

There were indications of fuel leakage at the flange interface of the fuel supply lines where the coupling had separated including discoloration from fluid pooling in the strut compartments and streaking down the left engine cowling.

Fuel Coupling (Credit: Boeing AMM via NTSB)

Fuel Coupling (Credit: Boeing AMM via NTSB)

There was no safety lockwire present on either the body or nut side of the fuel coupling as required in the Boeing aircraft maintenance manual (AMM), and no broken lockwire was recovered in the surrounding strut compartments.

Fuel Coupling As Found, Dynamic Boeing 737-269ER N251MY (Credit: NTSB)

Fuel Coupling As Found, Dynamic Boeing 737-269ER N251MY (Credit: NTSB)

Exemplar Installation (Credit: NTSB)

Exemplar Installation (Credit: NTSB)

A material examination of the fuel supply lines and coupling components verified that the parts met dimensional drawing specifications and were free of defects or damage that would have affected normal operation.

In 2012, the airplane was placed in storage until 2015 when it was taken out of storage and prepared for leasing to Dynamic.

A Boeing Service Letter recommending replacement of fuel line flexible coupling (Wiggins coupling) retainer components was issued on March 14, 2000. Maintenance records of the accident airplane indicate the last time this service was performed was by Kalitta Air LLC on October 12, 2012 just prior to going into storage in Arizona.

Additionally, the strut fuel feed line components, while not specifically called out, could be looked at during a Zonal Inspection (General Visual) of the area during a 1C interval. The last Zonal Inspection was accomplished May 5, 2015, by Kalitta Air LLC.

About 240 flight hours were logged between the aircraft returning to service and the accident.

The right over-wing exit was opened by a passenger, but the slide did not deploy. Testing at the manufacturer revealed a misalignment in the pull-force increase mechanism created a binding in the firing cable.

Safety Action

Dynamic International Airways issued a Fleet Campaign Directive to inspect the remainder of their fleet.  No other instances of improper installation were found.

NTSB Probable Cause

The separation of the flexible fuel line coupling and subsequent fuel leak due to the failure of maintenance personnel to install the required safety lockwire. Contributing to the severity of the accident was the initiation of the evacuation before the right engine was shut down which led to the passenger’s injury.

Safety Resources

We have previously written about another premature evacuation Premature A319 Evacuation With Engines Running and a significantly delayed evacuation: Delta MD-88 Accident at La Guardia 5 March 2015

Also see the RAeS Specialist Paper: Emergency Evacuation of Commercial Passenger Plane  UPDATE 7 July 2020: Updated RAeS Passenger Evacuation Paper now available

Also see:

Plus our review of The Field Guide to Understanding Human Error by Sidney Dekker presented to the Royal Aeronautical Society (RAeS): The Field Guide to Understanding Human Error – A Review

Aerossurance worked with the Flight Safety Foundation (FSF) to create a Maintenance Observation Program (MOP) requirement for their contractible BARSOHO offshore helicopter Safety Performance Requirements to help learning about routine maintenance and then to initiate safety improvements:

mop

Aerossurance can provide practice guidance and specialist support to successfully implement a MOP.


Aerossurance has extensive air safety, operations, SAR, airworthiness, human factors, aviation regulation and safety analysis experience.  For practical aviation advice you can trust, contact us at: enquiries@aerossurance.com

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