Report: Wrong engine shut down following engine failure on Jetstream 41 caused Durban crash

Investigators of the South African CAA released the final report of their investigation into the cause of a September 2009 fatal accident involving a Jetstream 41 twin turboprop airplane at Durban.

The aircraft commenced its take off roll from runway 06 at Durban (DUR) and shortly before it became airborne a catastrophic failure occurred in the nr.2 (right hand) engine due to a fatigue failure of the second stage rotating air seal. It continued to climb to an altitude of about 500 feet AMSL. Immediately after raising the undercarriage, the nr.1 (left hand) engine spooled down from 100% to zero within seven seconds. The aircraft then descended and the stick shaker activated. The airplane force landed in a small field and skidded before coming  to rest with the fuselage broken in two and detached from the wings.

The Probable Cause was determined as follows:

Engine failure after takeoff followed by inappropriate crew response, resulting in the loss of both lateral and directional control, the misidentification of the failed engine, and subsequent shutdown of the remaining serviceable engine.
Contributing factors:

• Separation of the second-stage turbine seal plate rim;
• Failure of the captain and first officer to implement any crew resource management procedures as prescribed in the operator’s training manual;
• The crew’s failure to follow the correct after take-off engine failure procedures as prescribed in the aircraft’s flight manual.

More information:

• ASN Accident Description
• SA CAA Final report (PDF)

EASA issues emergency AD on Trent engines following Qantas A380 engine failure

The European Aviation Safety Agency (EASA) issued an Emergency Airworthiness Directive (AD) for Rolls Royce RB211 Trent 900 series engines following a recent incident involving  such an engine on a Qantas A380.

The incident happened on November 4, 2010 when engine nr 2. on a Qantas Airbus A380, VH-OQA, suffered an uncontained failure shortly after takeoff from Singapore.

Analysis of the preliminary elements from the incident investigation shows that an oil fire in the HP/IP structure cavity may have caused the failure of the Intermediate Pressure Turbine (IPT) Disc.

This condition, if not detected, could ultimately result in uncontained engine failure potentially leading to damage to the aeroplane and hazards to persons or property on the ground.

For these reasons and pending conclusion of the incident investigation, the AD requires repetitive inspections of the Low Pressure Turbine (LPT) stage 1 blades and case drain, HP/IP structure air buffer cavity and oil service tubes in order to detect any abnormal oil leakage, and if any discrepancy is found, to prohibit further engine operation.

 

Note: This emergency AD was superseded by a EAD 2010-0242-E on November 22:  http://www.caa.co.uk/docs/33/easa_ad_2010_0242_E.pdf

 

Four recent uncontained engine failure events prompt NTSB to issue urgent safety recommendations to FAA

The National Transportation Safety Board issued two urgent safety recommendations to the Federal Aviation Administration (FAA) following four recent events in which the aircraft experienced an uncontained engine failure of its GE CF6-45/50 series engine.

The first recommendation asks that the FAA require operators of aircraft equipped with a particular model engine to immediately perform blade borescope inspections (BSI) of the high pressure turbine rotor at specific intervals until the current turbine disk can be redesigned and replaced with one that can withstand the unbalance vibration forces from the high pressure rotor. The second recommendation asks the FAA to require the engine manufacturer to immediately redesign the disk. The NTSB issued an additional recommendation for a requirement that operators perform a second type of inspection and another recommendation related to the engine manufacturer regarding the installation of the replacement disk.

All four recommendations apply to the low pressure turbine (LPT) stage 3 (S3) rotor disk in the General Electric (GE) CF6-45/50 series turbofan engines that can fail unexpectedly when excited by high-pressure (HP) rotor unbalance.
An uncontained engine event occurs when an engine failure results in fragments of rotating engine parts penetrating and exiting through the engine case. Uncontained turbine engine disk failures within an aircraft engine present a direct hazard to an airplane and its passengers because high-energy disk fragments can penetrate the cabin or fuel tanks, damage flight control surfaces, or sever flammable fluid or hydraulic lines. Engine cases are not designed to contain failed turbine disks. Instead, the risk of uncontained disk failure is mitigated by designating disks as safety-critical parts, defined as the parts of an engine whose failure is likely to present a direct hazard to the aircraft.
In its safety recommendations to the FAA, the NTSB cited four foreign accidents, which the NTSB is either investigating or participating in an investigation led by another nation, in which the aircraft experienced an uncontained engine failure of its GE CF6-45/50 series engine.

The date, location, and circumstances of these four events (none had injuries or fatalities) are as follows:

On July 4, 2008, a Saudi Arabian Airlines (Saudia) Boeing 747-300 experienced an engine failure during initial climb after takeoff from Jeddah, Kingdom of Saudi Arabia. This investigation has been delegated to the NTSB.

On March 26, 2009, an Arrow Cargo McDonnell Douglas DC-10F, about 30 minutes after takeoff from Manaus, Brazil, experienced loss of oil pressure in one engine. The pilots shut down the engine and diverted to Medellin, Columbia. This investigation has been delegated to the NTSB.

On December 17, 2009, a Jett8 Cargo Boeing 747-200F airplane was passing through 7,000 feet above ground level (agl) when the flight crewmembers heard a muffled explosion and immediately applied left rudder. With one engine losing oil pressure, the airplane returned to land at Changi, Singapore. The NTSB is participating in the investigation that is being led by the Air Accident Investigation Bureau of Singapore.

On April 10, 2010, an ACT Cargo Airbus A300B4 experienced an engine failure while accelerating for takeoff at Manama, Bahrain. The crew declared an emergency, rejected the takeoff, activated the fire suppression system, and evacuated the airplane. The NTSB is participating in the investigation that is being led by the Bahrain Ministry of Transportation – Civil Aviation.
The four recommendations to the FAA are as follows:
1. Immediately require operators of CF6-45/50-powered airplanes to perform high pressure turbine rotor blade borescope inspections every 15 flight cycles until the low pressure turbine stage 3 disk is replaced with a redesigned disk that can withstand the unbalance vibration forces from the high pressure rotor. (Urgent)

2. Require operators of CF6-45/50-powered airplanes to perform fluorescent penetrant inspections of CF6-45- 50- low pressure turbine stage 3 disks at every engine shop visit until the low pressure turbine stage 3 disk is replaced with a redesigned disk that can withstand the unbalance vibration forces from the high pressure rotor.

3. Immediately require General Electric Company to redesign the CF6-45/50 low pressure turbine stage 3 disk so that it will not fail when exposed to high pressure rotor unbalance forces. (Urgent)

4. Once General Electric Company has redesigned the CF6- 45/50 low pressure turbine (LPT) stage 3 disk in accordance with Safety Recommendation [3], require all operators of CF6-45/50-powered airplanes to install the newly designed LPT S3 at the next maintenance opportunity.