Bombardier CL 600 2B19 N8986B

Summary

On 23 January 2017 at about 23:30 local time, a Bombardier CL 600 2B19 registered N8986B, operated by Endeavor Air, was involved in an incident near Baltimore, Maryland, United States. 51 people were on board and nobody was injured. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

23 January 2017 at 23:30

Classification

Incident

Location

Baltimore, Maryland, United States

Nearest airport

Baltimore/Washington Intl Thur (BWI)

Coordinates

39.1775, -76.6689

Aircraft

Bombardier CL 600 2B19

Registration

N8986B

Category

Airplane

Year built

2004

Engines

2

Operator

Endeavor Air

Operating rule

Part 121: Air Carrier

Phase of flight

Not recorded

Route

Baltimore → Covington

Aircraft damage

Not recorded

Weather

Unk

Light

Night

NTSB number

ENG17IA008

Nobody was injured.

A Bombardier CRJ200 No. 2 engine failure due to the separation of a fan blade airfoil at a low cycle fatigue crack that originated at the forward fan blade pin hole attachment. The separated fan blade had previously undergone a hot form repair and both metallurgical analysis and repair records indicated that the lance/shot peen step required to restore sufficient residual stress levels to the blade material was not completed.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The No. 2 engine fan blade airfoil separation was caused by a low cycle fatigue crack that originated at the forward blade pin hole attachment tang due to insufficient residual stress (hoop stress) levels in the Ti-8-1-1 blade material. The fan blade had undergone a hot form repair following a bird strike incident in December 2007 to restore the blade profile. During the hot form repair process the blade was placed in a ceramic die and heated to 1150-1200oF to restore the blade geometry. The hot form process relieved the compressive residual stress layer in the fan blade and the layer was not properly restored with a lance peen/shot peen step as called out in the GE Standard Repair Manual. There was visual evidence of 100% lance peen/shot peen coverage on the fan blade attachment pin holes surfaces that was identified during the materials lab examination, but the peen marks were most likely formed during the original fan blade manufacturing process. When the fan blade airfoil separated during the incident it was contained by the engine fan case containment system. The fan blade impact with the fan case containment system resulted in a bulge in the Kevlar wrap that damaged the attaching hardware at the fan cowl flanges, and the cowl subsequently separated when exposed to the jet stream. When the fan cowls separated from the engine they impacted the thrust reverser translating cowl and core cowl and resulted in gouging and surface buckling. The fan blade airfoil separation caused a fan imbalance that led to high No. 2 engine vibration levels. The high vibration levels caused the engine transition case to LPT flange separation, AGB housing fracture, and starter damage.

Quoted verbatim from the NTSB record.