Date: March 26th, 2024
Aircraft: Canadair CRJ-100
Registration: ZS-CMK
Operator: CemAir
Flight Number: 5Z-404
Route: Johannesburg (FAOR) to George (FAGG), South Africa
Occupants: Not disclosed
Injuries: None reported
Damage: Starboard cockpit windshield
Status: Investigation concluded, aircraft returned to service
Incident Summary
On March 26th, 2024, CemAir flight 5Z-404 from Johannesburg to George, South Africa, experienced a shattered first officer’s windshield while cruising at FL300 approximately 10 minutes prior to the top of descent. The crew donned oxygen masks, declared an emergency, and performed an emergency descent to FL090 before executing a safe landing on runway 11 at George Airport (FAGG).
The South African Civil Aviation Authority (SACAA) opened an investigation, releasing its final report in December 2024.
Sequence of Events
1. Departure and Cruise:
• The CRJ-100 departed Johannesburg at 0810Z under instrument flight rules (IFR).
2. Windshield Shatter:
• At approximately 0930Z, while cruising at FL300, the starboard (right-side) cockpit windshield cracked.
• The first officer, who was the pilot flying, donned their oxygen mask and declared an emergency.
3. Emergency Descent:
• Air Traffic Control (ATC) at Cape Town cleared the aircraft to descend to FL090.
4. Landing:
• The aircraft safely landed on runway 11 at George Airport.
5. Inspection and Findings:
• Significant fractures were observed on the outer glass layer of the windshield.
• Extensive delamination occurred between the outer and intermediate layers at the heating element interface.
Investigation Findings
Probable Cause:
The SACAA identified electrical arcing in the heating element as the primary cause of the windshield failure. This arcing resulted in localized high temperatures and stress, causing a crack and subsequent delamination.
Contributing Factors:
1. Heating Element Malfunction:
• The heating element’s interface suffered delamination, which reduced its effectiveness and caused temperature gradients.
2. Moisture Ingress:
• Moisture penetration between the glass layers likely exacerbated the delamination and arcing.
3. Glass Stress Limits:
• The delamination-induced stress exceeded the tempered glass layer’s limits, leading to the fracture.
Safety Analysis
1. Cockpit Windshield Design:
• Aircraft windshields are designed to withstand significant stress and environmental conditions, including thermal cycles and electrical loads.
• Delamination and electrical arcing represent critical failures that compromise windshield integrity.
2. Crew Response:
• The crew’s prompt actions to don oxygen masks and initiate an emergency descent ensured the safety of all onboard.
3. Maintenance Considerations:
• Routine inspections and maintenance of cockpit windshields and heating elements are essential to detect early signs of delamination or moisture ingress.
Recommendations
1. Enhanced Maintenance Protocols:
• Operators should conduct more frequent inspections of cockpit windshields, particularly around heating elements, to identify potential delamination or moisture ingress.
2. Manufacturer Guidelines:
• Review and update manufacturer maintenance and inspection procedures for windshield assemblies.
3. Crew Training:
• Emphasize emergency procedures for handling windshield failures, including the use of oxygen masks and emergency descent protocols.
Conclusion
The CemAir CRJ-100 incident highlights the critical importance of maintaining windshield integrity and the effectiveness of the crew’s emergency response. Electrical arcing and delamination in the windshield’s heating element were identified as the root causes. The incident serves as a reminder for operators and manufacturers to prioritize regular inspections and improvements in windshield assembly design and maintenance protocols.
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