History of Flight
On December 9, 2019, at approximately 1450 Eastern standard time, a Bombardier DHC-8-301 (registration C-GNON) sustained minor damage during an incident near Keene, New Hampshire. The flight, operated as a Title 14 Code of Federal Regulations Part 129 international passenger service, was en route from Montreal-Pierre Elliott Trudeau International Airport (YUL) to Bradley International Airport (BDL) with two pilots, one flight attendant, and 15 passengers aboard. No injuries were reported.
According to written statements from the flight crew, the flight proceeded normally from departure through the initial approach into BDL. During descent at about 21,500 feet mean sea level, the first officer detected a smell of smoke and subsequently observed smoke and flames emanating from the upper forward corner of the right windshield. The crew donned oxygen masks and smoke goggles and requested priority handling from air traffic control. The first officer deployed a fire extinguisher on the fire and requested vectors to the nearest airport, Keene Dillant-Hopkins Airport (EEN) in Keene, New Hampshire. The fire reignited, requiring a second application of the extinguisher. The captain initially switched off both AC and DC generators, suspecting an electrical fire, then turned the windshield heat switch to OFF and re-engaged the generators.
Unable to find EEN airport data on company-supplied iPads, the crew decided to continue to BDL, as the fire was extinguished and they had already briefed the approach. Following the fire, the right windshield cracked during descent. The captain reduced airspeed to 180 knots and maintained a cabin pressure differential of 3 psi. The first officer reported consulting emergency checklists but found no specific procedure for a windshield fire. The airplane landed at BDL at about 1526 EST, where airport fire trucks met the aircraft on the runway. After confirming no remaining smoke or fire, the aircraft proceeded to the gate.
Aircraft Information
The Bombardier DHC-8-300 is equipped with two main windshields of laminated glass construction. The right windshield, installed on November 2, 2014, had accumulated 10,618.2 hours and 11,762 cycles. The windshield was manufactured with multiple layers: chemically tempered glass, a conductive heating film, urethane interlayer, vinyl interlayer, and additional chemically tempered glass layers. It was a plug design secured by aluminum retainers, with a polysulfide moisture seal protecting interlayer materials from moisture ingress.
The anti-ice function, provided by the conductive heating film, is controlled by a HEAT switch on the left overhead console. The rotary switch has three positions: OFF, WARM UP (partial power to preheat and prevent thermal shock), and NORM (full power to maintain windshield temperature at 108°F ±4°F). Sensors monitor temperature; power is cut if temperature reaches 122°F ±4°F. An overheat condition triggers an amber caution light (L WSHLD HOT or R WSHLD HOT) on the caution/warning panel, which extinguishes if the HEAT switch is set to WARM UP.
Windshield serial number indicated it was a new unit completed on the 365th day of 2013.
Maintenance History
The Jazz maintenance program included three windshield inspection tasks. A general visual inspection of the moisture seal every 1,600 hours or 365 days was last performed on October 28, 2019. An internal general visual inspection of the flight compartment above the floor (including windshields) every 11,000 hours or 3,652 days was last done on January 9, 2018. An external general visual inspection of the flight compartment above the floor every 5,500 hours or 1,826 days was also last performed on January 9, 2018. No discrepancies were reported.
Additionally, a Fleet Campaign Directive required repetitive torque checks, witness marks, and application of Humiseal to windshield electrical connections every 3,000 hours; it was last applied to the incident windshield on April 3, 2019. Transport Canada Airworthiness Directive CF-2017-25 was complied with on January 9, 2018. The average life of DHC-8-200/-300 windshields (PPG) is about 8.2 years based on limited fleet data; Jazz replaces windshields on condition and does not track life.
Damage and Examination
The right windshield sustained burning and charring damage concentrated at the terminal block area, and the inner glass ply was fractured. Adjacent interior trim components near the forward upper edge also showed burning and charring. The power and sensor wires to the windshield were cut, and the windshield was removed for examination.
Fractures on the inboard glass ply formed a sparse network. Minor cloudiness of the interlayer indicated moisture ingression between bus bars and the edge. Minor erosion of the hump seal along upper and aft edges was noted, with no evidence of repair.
The terminal block remained attached, but burning was concentrated at the L2 terminal location. The L2 terminal insert had separated from the block and remained attached to the wire. Screws at power and sensor connections were installed with lock washers; torque striping was evident on all screws except at L2, where it was burned away. No Humiseal was found at L1 and L2 terminal locations. Disassembly revealed no cross-threading or other discrepancies.
All braid wires except the L2 wire were intact around the edge of the laminate and attached to the terminal block. A small section of the L2 wire remained embedded in charred sealant below the L2 insert; another section was melted away above the terminal block. Melted glass was observed near the missing L2 wire, and inner glass ply fractures originated from that area.