Accident Ilyushin Il-76TD 4L-GNI,

ASN Wikibase Occurrence # 321208

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Date:	Sunday 28 November 2010
Time:	01:45
Type:	Ilyushin Il-76TD
Owner/operator:	Sun Way
Registration:	4L-GNI
MSN:	43452546
Year of manufacture:	1984
Total airframe hrs:	8357 hours
Cycles:	3373 flights
Engine model:	Soloviev D-30KP
Fatalities:	Fatalities: 8 / Occupants: 8
Other fatalities:	3
Aircraft damage:	Destroyed, written off
Category:	Accident
Location:	ca 5 km W of Karachi-Jinnah International Airport (KHI) - Pakistan
Phase:	Initial climb
Nature:	Cargo
Departure airport:	Karachi-Jinnah International Airport (KHI/OPKC)
Destination airport:	Khartoum-Civil Airport (KRT/HSSS)
Investigating agency:	PakCAA
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
An Ilyushin 76TD cargo plane, registered 4L-GNI, was destroyed in an accident near Karachi-Jinnah International Airport in Pakistan. All eight occupants and three persons on the ground were killed.
The airplane operated on a cargo flight from Karachi-Jinnah International Airport (KHI), Pakistan to Douala, Cameroon with a planned en route stop at Khartoum, Sudan. The flight was loaded with 30.5 tons of relief supplies (tents).
After completion of necessary pre flight requisites by the flight crew, the cockpit crew contacted Karachi Airport at 01:14 hours local time and informed about their readiness to start for Khartoum. After receiving permission from the air traffic controller, the crew started the engines between 01:21 and 01:24. On previous flights the crew had encountered problems starting engine no.4. On those occasions the engine was finally started after switching on the Engine Anti Ice System. At Karachi, the flight crew proactively activated the Engine Anti Ice System before starting engine no.4.
The most probable reason of abnormal starts of the engine no.4 was reduction of compressor efficiency because of blade wear. The service wear of blades increases axial and radial clearances and the blade surface becomes rough, thus reducing the compressor efficiency. With the inlet guide vanes heating mode on, the amount of air through the compressors first stages increases thus improving the start reliability.
The crew then taxied the plane to runway 25L and took off at 01:43 hours. Shortly after takeoff, as the aircraft was climbing through an altitude of 100 meters, the no.4 engine suffered an uncontained failure. The airspeed was 325 km/h and undercarriage had been retracted. The remaining three engines continued working on takeoff power.
The aircraft banked right, which the pilot tried to counteract with ailerons and rudder. The no.4 engine was then set to idle and subsequently shut down.
Despite fully deflected ailerons and spoilers to create a left bank, the aircraft continued in a right bank. Right bank had increased to 32° while the recorded deflection of the rudder was -24° (to the left) and elevator to -10° for pitch up. The aircraft reached a height 140 m before it entered a descent.
At 01:44 the bank angle became 71° to the right and the aircraft continued moving to right and impacted buildings that were under construction.

Cause of Occurrence:
The cause of the occurrence was uncontained failure of the 2nd stage disk of LP compressor of Engine # 4 due to fatigue fracture which resulted in in-flight fire and damage to adjacent areas of right wing / flaps to an extent that flight could not be sustained.
The use of mishap engine beyond its manufacturers assigned life without assessment and life enhancement by the manufacturer was the cause of its uncontained fatigue failure.

Accident investigation: