Summary
On January 23, 2017, at approximately 1830 eastern standard time, an Endeavor Air Bombardier CRJ200, registration N8986B, experienced a fan blade separation in the No. 2 (right) engine during initial climb from Baltimore-Washington International Airport (BWI), Baltimore, Maryland. The crew reported a loud bang followed by increased vibration, a turbine inlet temperature warning, and a thrust reverser warning. They declared an emergency, shut down the No. 2 engine, and returned to BWI for an uneventful single-engine landing. There were no reported injuries to passengers or crew. The flight was operated under 14 CFR Part 121 as a scheduled service from BWI to Cincinnati/Northern Kentucky International Airport (CVG), Covington, Kentucky.
Damage to the Airplane
The fan blade separation did not cause damage to the fuselage or right wing. The No. 2 engine fan cowl halves separated in flight and were not recovered. The thrust reverser translating cowls and core cowls sustained impact damage including gouging and minor surface buckling, with damage radially inward toward the engine centerline. No evidence of engine uncontainment was found.
Examination and Testing
Visual examination of the No. 2 engine at BWI revealed one fan blade foil separated at the blade root pin hole attachment. The separated airfoil and the inboard half of the forward pin hole attachment tang were embedded in the fan case honeycomb and Kevlar containment layers. All remaining fan blades were intact but showed leading edge impact damage. The low pressure turbine (LPT)-to-transition case flange bolts were fractured, creating a 7/16-inch gap and allowing the LPT case and jet pipe to rotate 30 degrees clockwise. The accessory gearbox (AGB) housing was fractured near the starter, with a missing piece; two of three AGB attachment points had failed. The engine starter housing was fractured downstream of the air valve.
Metallurgical analysis of the separated fan blade at the NTSB material laboratory found that the forward and middle blade tang fracture surfaces had cracks originating from the inner diameter pin hole surface, consistent with low cycle fatigue (LCF). No nicks, dents, or corrosion were observed near the crack origins. Fatigue striation counting estimated that the crack grew over 2,560 cycles between initiation and separation. Material composition and geometry matched drawing specifications for Ti-8-1-1. The blade root had 100% lance peen/shot peen coverage on recovered pin hole surfaces. Residual stress analysis revealed levels well below those measured on other blades from the incident engine and from other fleet operators.
Fan Blade History
Fan blade serial number KGACA251 was manufactured in December 2010 by Tect-Utica using Allvac Ti-8-1-1 bar stock and entered service in April 2001. It was damaged in a bird strike in December 2007 and sent to Airfoil Technologies International-UK (ATI-UK) for hot form repair, after which it was recertified in February 2008. The blade was installed in another engine in April 2008 and then moved to the incident engine in June 2008, accumulating 4,234 cycles at that time. During a shop visit in June 2012, it underwent major blend, polish, coating, and eddy current inspection per service bulletin 72-0106, with 10,736 cycles. At the time of separation, the blade had reached 18,063 total cycles.
Corrective Actions
Following the incident, GE released all operators wires (AOW) to notify CF34-3 operators and request eddy current inspection results for fan blade pin holes per service bulletins 72-0106 and 72-0091. GE also identified suspect fan blades that had undergone hot form repair at ATI-UK without documented shot peening/lance peening. Service bulletins 72-0314 and 72-0306 (September 2017) listed suspect blades and recommended inspection; operators could scrap or perform a bushing repair to reestablish residual stress. Additional bulletins in January 2018 requested review of repair records for all CF34-3 fan blades to identify any other blades repaired at ATI-UK.