A Lufthansa Cityline CRJ900 jet en-route from Munich to Cologne was forced to return to Munich after suffering a cracked windshield. The incident occurred while performing Lufthansa Cityline flight LH-1982 from Munich International Airport (MUC) to Cologne Bonn Airport (CGN) on Friday, February 21st.

The Bombardier CRJ-900, registration number D-ACNG was en route to Cologne cruising at FL240, 25 nautical miles southeast of Frankfurt am Main Airport when the incident occurred according to information from The Aviation Herald. The pilots of the twin-engine CRJ900 jet took action descending to FL220 before deciding to return to Munich.

The 86-passenger regional jet landed safely back in Munich just 30 minutes after the decision was made to do so. The aircraft remained on the ground for 30 hours before returning to service.

What causes a cracked windshield?

Aircraft windscreens or windshields are made of several layers of glass that are designed to deal with air pressure changes and withstand the impact of a bird strike. They are, however, not indestructible. In fact, windshields may suffer cracks more often than you might think. A common cause of aircraft windshield cracks occurs when planes encounter severe hailstorms.

A windshield may also crack due to incorrect heating. Modern aircraft have electronically heated windows that sometimes crack due to a short-circuit. This causes uneven temperatures in the glass. The age of the aircraft and the number of flight cycles can also be a factor due to stress levels put on the glass over a long period of time.

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After reporting the crack the CRJ900 returned to Munich. Photo: Lufthansa

Is a cracked windshield dangerous?

Windshields in aircraft contain two layers of thick glass with a middle layer of plastic used to conduct heat. If one layer of glass should crack or break, the second layer of glass is designed to maintain air pressure within the cockpit.

When a heating problem is the cause, it is the outer pane of glass that is susceptible to cracking. Most windshield cracks occur while the aircraft is climbing, but cracking can also happen while at cruising altitude, as is evident by this Lufthansa Cityline incident.

Should a windshield crack during the flight, pilots are trained to descend to a lower altitude where the air pressure is less intense. Following this, the procedure is to divert to the nearest airport if necessary.

The CRJ900 regional jet is perfect for smaller airports

Built by Bombardier in Montreal, Canada, the CRJ900 regional jet is the ideal choice for smaller airports in the Lufthansa network, ferrying passengers to the airline's main hubs in Frankfurt and Munich. Most commonly found in a 2-2 configuration, every passenger is guaranteed either a window or aisle seat.

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Lufthansa Cityline CRJ900s can carry 84 passengers. Photo: Laurent ERRERA Wikimedia Commons

The Lufthansa Cityline CRJ900 is 33.5 meters long and flies at a speed of 860 Kph (534 mph) and has a range of 3,408km (1,976 nm). Designed to operate without the need for external stairs or an air-gate, the CRJ900 even has special cargo compartments that allow passengers to stow and retrieve luggage directly before boarding, or as soon as they get off the aircraft.

Have you flown on a CRJ aircraft before? What do you think about the experience? Please let us know in the comments section.