Bombardier DHC-8-402 N417QX

Summary

On 5 March 2013 at about 19:20 local time, a Bombardier DHC-8-402 registered N417QX, operated by Horizon Air, was involved in an incident near Danville, California, United States. 51 people were on board and nobody was injured. The aircraft was slightly damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

5 March 2013 at 19:20

Classification

Incident

Location

Danville, California, United States

Nearest airport

Norman Y. Mineta San Jose Int (SJC)

Coordinates

37.8394, -122.0033

Aircraft

Bombardier DHC-8-402

Registration

N417QX

Category

Airplane

Year built

2004

Engines

2

Operator

Horizon Air

Operating rule

Part 121: Air Carrier

Phase of flight

Not recorded

Route

San Jose → Boise

Aircraft damage

Minor

Weather

VMC

Light

Day

NTSB number

WPR13IA144

Nobody was injured.

The failure and separation of a section of the No. 2 engine's combustion chamber's small exit duct (SED), which created an airflow disruption that led to an engine surge and subsequent fire. Contributing to the accident was the insufficient weld penetration that remained totally contained within the SED outer dome and did not penetrate through to the inner duct as required by the manufacturing specifications.

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

Read the full NTSB narrative

The flight was climbing through flight level 200 when the flight crew received a No. 2 engine audible fire warning, which was accompanied by a bang sound. The crew subsequently shut the No. 2 engine down and discharged both of the engine's fire extinguishing bottles. The cabin crew reported no visible fire, but the flight crew continued to receive a fire indication. The captain then declared an emergency, began a descent to the departure airport, and landed about 9 minutes after the event. After the airplane was stopped on the runway and the No. 1 (left) engine was shut down, an emergency evacuation was conducted using the main cabin door. An initial assessment by company personnel indicated that the fire damage to the airplane was limited to what was visible on the aircraft's exterior. A visual postincident examination of the engine revealed that sooting was present on external case surfaces, which were concentrated on the aft half of the No. 2 engine. A disassembly of the engine confirmed that about half of the SED outer dome within the combustion section had separated and was subsequently ingested into the gas path. To determine the reason for the separation, three locations on the outer dome were sectioned and examined. All three locations exhibited insufficient weld penetration so that the welds remained totally contained within the SED outer dome and did not penetrate through to the inner duct as required by the manufacturing specifications.

Quoted verbatim from the NTSB record.