Pilot Debrief

AIRBUS A319 112 near New Orleans, LA — 2015-05-05

Final reportCEN15IA225
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Date
2015-05-05
Location
New Orleans, LA, USA
Aircraft
AIRBUS A319 112
Registration
N941FR
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Cruise

Probable cause

The ingression of moisture into the windshield’s laminate layer, which induced electrical arcing in the windshield heating system that subsequently cracked the outer glass pane of the windshield.

NTSB narrative

About 1 hour into the air carrier flight, the flight crew observed arcing and sparks along the bottom of the windshield. The flight crew then heard a popping sound and observed the windshield cracking. The crew subsequently declared an emergency, diverted the flight to another airport, and landed the airplane without further incident. The captain did not remember if any breakers popped or if there was an electronic centralized aircraft monitor message during the event. Postincident examination of the windshield revealed evidence of repairs to the moisture seal along the windshield's entire upper and aft edges, and the windshield exhibited typical signs of aging. The interlayer material adjacent to the edges of the windshield was cloudy and cracked. Evidence of moisture ingression into the laminate around the edges of the windshield was found. The moisture ingression at the lower, forward corner of the windshield had progressed inward to the bus bar. Brown, bubbled interlayer material was found adjacent to the windshield fracture origins, indicating that the windshield heat was powered at the time of fracture and that electrical arcing had occurred. The moisture likely disrupted the electrical path between the bus bar and the windshield's electrical heating film, which resulted in the electrical arcing and subsequent cracking of the windshield's outer glass pane. The operator's maintenance program required periodic inspections of the incident part number windshields in its fleet, which were in accordance with the windshield manufacturer's recommended inspections. A review of the airplane's maintenance records revealed that the windshield was inspected about 11 months before the incident. During this inspection, the windshield's moisture seal was noted to be eroded and was subsequently repaired. The incident windshield was last inspected 8 days before the accident and included a detailed inspection of the moisture seal for cracks and erosion, and no findings were noted. The delamination, discoloration, interlayer microflakes, bubbling, and burn spots were within the specified limits of the airplane maintenance manual. The incident windshield was installed on the airplane at manufacture, and it had accumulated 38,085 flight hours since its installation. The latest windshield design, which entered service 5 years before the incident, includes enhancements that reduce the potential for moisture ingress and electrical arcing. To date, there have been no reported electrical arcing events or age-related failures of the latest windshield design.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Flight crew could have pulled the circuit breaker for the windshield upon observing arcing.

NTSB coding

  • Sys/Comp malf/fail (non-power) · Enroute-cruise

Evidence available

  • 7 docket documents
View NTSB final reportView NTSB docket

Docket documents7

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