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ASN Wikibase Occurrence # 144455
Last updated: 1 December 2021
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Date:17-FEB-2012
Time:08:30
Type:Silhouette image of generic B190 model; specific model in this crash may look slightly different
Beechcraft 1900D
Owner/operator:Great Lakes Airlines
Registration: N210GL
MSN: UE-210
Fatalities:Fatalities: 0 / Occupants:
Aircraft damage: Minor
Category:Incident
Location:Denver International Airport - KDEN, Denver, CO -   United States of America
Phase: Standing
Nature:Passenger - Scheduled
Departure airport:Laramie, WY (KLAR)
Destination airport:Denver, CO (KDEN)
Investigating agency: NTSB
Narrative:
During a post flight inspection the pilot discovered a hydraulic leak on the nose landing gear that was emanating from a crack in the nose landing gear end cap. The end cap was examined and found to have failed in fatigue that initiated from multiple origins at an internal diameter. The fatigue had propagated significantly into the wall thickness of the end cap and through the thickness at one location. The striation count revealed that the fatigue crack had initiated and been growing in the end cap for at least 15,305 cycles. The end cap had been inspected using an ultrasonic method recommended by the manufacturer 337 cycles prior to the incident. The crack was present at the time of the inspection which indicated that the inspection method was ineffective in detecting the crack. The timing of the end cap inspection was in compliance with the manufacturer’s recommendation. Examination of the microstructure of the material revealed that the longitudinal grain direction was oriented parallel to the shuttle valve bore in the end cap. Resistance to fatigue can be improved by aligning the principle tension stresses in the end cap with the longitudinal grain direction. It is probable that the manufacturer had determined that the grain direction was a contributing factor to fatigue failure in the end cap and revised the end cap drawing to require a grain direction along the longitudinal axis of the end cap in February 2010. No engineering data to support the drawing revision was made available.
Probable Cause: A failure of the nose landing gear end cap due to fatigue. Contributing to the failure were the ineffective inspection and the unknown effect of grain direction on fatigue life.

Sources:

NTSB

Accident investigation:
cover
  
Investigating agency: NTSB
Status: Investigation completed
Duration: 1 year and 5 months
Download report: Final report


Images:

Photo of N210GL courtesy AirHistory.net


Denver - International (KDEN / DEN)
12 October 2011; (c) Alastair T. Gardiner

Revision history:

Date/timeContributorUpdates
16-Mar-2012 19:03 Geno Added
26-Sep-2012 07:52 harro Updated [Aircraft type, Source, Narrative]
28-Nov-2017 20:17 ASN Update Bot Updated [Time, Operator, Total occupants, Other fatalities, Departure airport, Destination airport, Source, Narrative]

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