Martinair MD11 at Aguadilla on Aug 30th 2013, rejected takeoff due to uncontained engine failure

Last Update: April 5, 2016 / 14:22:33 GMT/Zulu time

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Photo of Martinair PH-MCW, McDonnell Douglas MD-11 — Martinair PH-MCW, McDonnell Douglas MD-11 (Photo credit: Hawkwindzoo - Steve Walsh / Flickr / License: CC by-nd)

Incident Facts

Date of incident
Aug 30, 2013

Classification
Incident

Cause
Rejected takeoff

Airline
Martinair

Departure
Aguadilla, Puerto Rico

Destination
London Stansted, United Kingdom

Aircraft Registration
PH-MCW

Aircraft Type
McDonnell Douglas MD-11

ICAO Type Designator
MD11

A Martinair McDonnell Douglas MD-11, registration PH-MCW performing freight flight MP-1156 from Aguadilla (Puerto Rico) to London Stansted,EN (UK), was accelerating for takeoff from Aguadilla when a fire in the left hand engine (PW4462) prompted the crew to reject takeoff at low speed (17 knots over ground). Emergency services responded.

The FAA reported on takeoff roll the #1 engine caught fire, the takeoff was rejected. The aircraft subsequently taxied back to the apron, the engine received unknown damage.

On Dec 20th 2013 the NTSB reported that the #1 engine suffered an uncontained low pressure turbine failure. Takeoff was rejected at 17 knots, airport emergency services responded but observed no fire. The aircraft taxied back to the apron under own power. The engine received multiple holes through the left and right hand side of the engine aft core cowl, there were numerous small punctures and impact marks on wing and gear. Initial inspection showed the PW4462-3 engine suffered a "partial LPT-to-turbine exhaust case (TEC) flange separation". The engine has been removed from the aircraft and sent for further analysis.

On Apr 4th 2016 the NTSB released their final report concluding the probable causes of the incident were:

an insufficiently robust flange attachment hardware design, which failed to contain engine components that were liberated during an LPT mechanical failure, resulting in engine/nacelle uncontainment.

A factor in the incident was the lack of a module-level LPT inspection and the lack of an inspection requirement to detect/monitor the LPT S4 for advanced sulfidation attack.

The NTSB reported that an engine examination showed that the P-flange attachment hardware was missing from 62 of 132 bolt holes, the local case was distorted and the P-flange separated by up to 2 inches. Debris recovered consisted of 71 pieces that were identified as bolt segments of 36 bolts.

Upstream of LPT stage 4 there were no faults and damage. Examination of stage 4 revealed an advanced corrosion attack at S4 vanes with all S4 blades fractured close to the platform. All S5 and S6 blades showed near platform separations. 4 S4 vane clusters and more than half of the vane clusters S5 and S6 were liberated.

The NTSB wrote: "Metallurgical examination of four exemplar S4 vane clusters found significant corrosion/oxidation consumption of vane airfoil wall thicknesses. Chemical analysis of the corrosion attack fronts revealed sulfur-rich particles, indicative of sulfidation as the corrosion mechanism. EDS and WDS spectra and elemental maps collected at multiple locations along the attack fronts confirmed a consistent sulfur presence and the presence of chromium. Inspection of the displaced S4 vane clusters found that corrosion-induced material loss resulting in loss of structural stiffness had allowed the clusters to disengage at the inner attachment. Four exemplar S4 blade fracture surfaces displayed machining-type LE damage typical of rotor contact with static hardware during operation. Metallurgical examination of the fracture surfaces immediately aft of the consumed LEs revealed high cycle fatigue crack propagation leading to airfoil overload fracture."

The NTSB anntotated: "The S4 LPT vane clusters installed in the LPT (P/N 51N674-01) were affected by Federal Aviation Administration (FAA) airworthiness directive (AD) 2012-14-09, however the engine was within the specified compliance."