Merpati MA60 near Bima on Dec 12th 2011, engine fire due to fuel leak

Last Update: September 11, 2015 / 14:15:57 GMT/Zulu time

Bookmark this article
Incident Facts

Date of incident
Dec 12, 2011

Classification
Report

Cause
Engine fire

Airline
Merpati Nusantara Airlines

Flight number
MZ-623

Departure
Bima, Indonesia

Destination
Denpasar, Indonesia

Aircraft Registration
PK-MZG

Aircraft Type
XIAN MA-60

ICAO Type Designator
MA60

A Merpati Nusantara Airlines Xian MA-60, registration PK-MZG performing flight MZ-623 from Bima to Denpasar (Indonesia) with 38 passengers and 5 crew, was climbing out of Bima when climbing through 4000 feet MSL the crew received a left DC generator caution indication, the generator was reset and the caution indication ceased. Climbing through 6000 feet the crew received a left hand engine (PW127J) fire indication and fire bell briefly, the indication and bell stopped, but re-occurred a short time after. The captain, pilot flying (39, ATPL, 4,814 hours total, 1,531 hours on type), observed clouds ahead and decided to stay clear of the clouds, the flight engineer was called to the cockpit and confirmed there was fire at the left hand engine. The crew feathered the left hand propeller, discharged the fire agent, cut off the left hand engine, the fire indication continued however, the second bottle was discharged, the fire indication continued. The first officer (40, ATPL, 1088 hours on type) advised ATC of their status and returned to Bima where the aircraft landed safely, attending emergency serivces reported no actual fire was seen, however there was evidencen the engine had been on fire. There were no injuries.

Indonesia's NTSC released their final report concluding the probable causes of the serious incident were:

The fire on the left engine was due to fuel leak on the fuel line fitting which was improperly tightened.

The delay of the pilot action had prolonged exposure the risk of the fire and jeopardize to the safety of the flight.

The NTSC reported that following landing an examination of the engine revealed evidence of fire at the bottom of the engine case below the hot and cold section of the engine. The fuel line underneath the fuel flow transmitter was found wet. The engine was cold cranked to increase the fuel pressure, a fuel leak was identified at the fuel flow transmitter at a rate of 21 droplets per minute as result.

The NTSC stated: "The original locking wire on the fuel fitting at the lower part of the fuel flow transmitter was intact. After opening the locking wire, the fitting was found to be not properly tightened. A further tightening could rotate the nut of about 5mm. After a retightening the fuel fitting, a cold cranking was performed and there was no fuel leak observed in the corresponding tube. There was no rework performed by the operator on the fuel flow transmitter. The installation of this particular fitting was performed by the aircraft manufacturer."

The NTSC reported that the flight data recorder stored 25 hours of data. Comparing the fuel flow of the occurrence flights with earlier flights it became apparent, that a discrepancy between left and right hand engine developed during the last 9 flights (including the occurrence flight) indicative of a fuel leak. The NTSC stated: "The fuel flow depends on the engine power setting. It reached its highest value at the take off stage, and it became smaller during climb. It is shown that the leak was at takeoff, and reduced gradually in the climb stage, and even ceased during cruise."

The NTSC analysed: "Fire initiated from the lower part of the cowling in front of the partition between hot and cold section of the engine number 1 where the fuel leak accumulated at that location. The fire moved upward crossing the frame bulkhead to the hot section."

The NTSC continued analysis: "During an inspection after the incident, the location of fuel leak was indicated at a tube and fitting which was found wet. The fuel leak was confirmed during cold cranking in which droplets of fuel leak observed at that location. The amount of fuel leak during cold cranking was also measured, i.e. 21 droplets per minute. During take-off the fuel pressure is much higher than during cold cranking. Therefore the fuel leak might be much larger during take-off and climb stage. The FDR revealed that the fuel flow difference reached up to 150 pph (pound per hour), or equivalent to 2.5 lbs/minute. During takeoff, the takeoff power was applied for approximately 2 minutes; therefore the fuel leak on the bottom of the engine contained approximately 5 lbs of fuel. Some part of the leaking fuel evaporated, and in the elevated temperature environment approaching the flash point a self-ignition could occur."

The NTSC analysed with regards to crew actions: "In this incident there was uncertainty in identifying the occurrence of fire. The fire warning was not immediately considered as the highest degree of warning. There was lengthy discussion between the pilots before a decision was made. This situation might arise from the fire warning that was not immediately perceived as engine fire. The pilot performed fire drill after the engineer informed that the fire on the left engine was visually observed. ... Discharging the fire extinguisher before shutting down the fuel supply would certainly un-effective to extinguish the fire. The incorrect sequence of the pilot actions indicated that the fire drill was not well pattern memorized. Schemata or mental model is a representation of the structure and operation of a system. Mental models are developed largely through experience, regular training and active interaction with the environment. The incorrect sequence could have been a result of insufficient pilot training, most specifically in in-flight engine fire."
Incident Facts

Date of incident
Dec 12, 2011

Classification
Report

Cause
Engine fire

Airline
Merpati Nusantara Airlines

Flight number
MZ-623

Departure
Bima, Indonesia

Destination
Denpasar, Indonesia

Aircraft Registration
PK-MZG

Aircraft Type
XIAN MA-60

ICAO Type Designator
MA60

This article is published under license from Avherald.com. © of text by Avherald.com.
Article source

You can read 2 more free articles without a subscription.

Subscribe now and continue reading without any limits!

Subscribe now
Are you a subscriber? Login
Subscribe

Read unlimited articles and receive our daily update briefing. Gain better insights into what is happening in commercial aviation safety.

Compare our plans

Send tip

Support AeroInside by sending a small tip amount.

Send tip

Related articles

Newest articles

Subscribe today

Are you researching aviation incidents? Get access to AeroInside Insights, unlimited read access and receive the daily newsletter.

Pick your plan and subscribe

Partner

Blockaviation logo

A new way to document and demonstrate airworthiness compliance and aircraft value. Find out more.

ELITE Logo

ELITE Simulation Solutions is a leading global provider of Flight Simulation Training Devices, IFR training software as well as flight controls and related services. Find out more.

Blue Altitude Logo

Your regulation partner, specialists in aviation safety and compliance; providing training, auditing, and consultancy services. Find out more.

AeroInside Blog
Popular aircraft
Airbus A320
Boeing 737-800
Boeing 737-800 MAX
Popular airlines
American Airlines
United
Delta
Air Canada
Lufthansa
British Airways