text: CLEVELAND (AP) — The Latest on a cracked window on a Southwest Airlines jet (all times local): 
   
   1:30 p.m. 
   
   Aviation experts say the slightest defect or micro-crack in a plane window can cause cracks like the one that forced a Southwest Airlines jet to land in Cleveland. 
   
   A Southwest spokeswoman says Flight 957 traveling from Chicago to New Jersey never lost cabin pressure and that the pilots didn't declare an emergency before landing Wednesday morning. 
   
   There were no reports of injuries. 
   
   Airline consultant Robert Mann says windows are periodically polished to remove the formation of tiny cracks in the acrylic windows from exposure to chemicals and the sun's rays. 
   
   He says the pilots were right to make a quick landing. 
   
   Anthony Roman, a commercial pilot and flight instructor based in New York, says problems with windows should be detected during regular inspections and maintenance. 
   
   ___ 
   
   12:45 p.m. 
   
   A Southwest Airlines spokeswoman says a plane forced to land in Cleveland because of a cracked window never lost cabin pressure. 
   
   Spokeswoman Brandy King also says the pilots didn't declare an emergency before landing Wednesday morning. 
   
   There were no reports of injuries after Flight 957 traveling from Chicago to New Jersey landed safely. 
   
   Southwest says there were no other mechanical problems with the plane that has been taken out of service. 
   
   The emergency landing comes two weeks after a Southwest Airlines plane made an emergency landing in Philadelphia after an engine exploded and a blew out a window in a deadly accident. 
   
   ___ 
   
   12 p.m. 
   
   A Southwest Airlines plane flying from Chicago to New Jersey has been forced to land in Cleveland after one of its windows cracked. 
   
   There were no reports of injuries after Flight 957 landed safely on Wednesday morning. 
   
   Dallas-based Southwest says that the plane diverted to Cleveland for a maintenance review after the issue on one of the multiple layers of window pane. 
   
   The emergency landing comes two weeks after a Southwest Airlines plane made an emergency landing in Philadelphia after an engine explosion and a blown out window. 
   
   A woman who was partly sucked out of that window was killed. ||||| Tweet with a location 
   
   You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more ||||| Mr. DeNyse said that immediately after the damage occurred, he heard gasps and saw a few passengers move away from the window. Over all, though, he described the flight as mostly normal. He said he could feel the plane slow down and descend after the damage occurred. He arrived in Newark only about an hour and a half behind schedule. 
   
   Airplane windows typically have multiple acrylic layers. To deal with the rigors of flight, their curve follows the shape of the fuselage, and their rounded edges make them less susceptible to stress-induced damage. 
   
   Southwest said the damage to the window on Wednesday had affected only one layer. 
   
   Jim Lee, the founder and chief executive of Lee Aerospace of Wichita, Kan., said plane windows are built to weather that kind of damage. 
   
   “On the 737, there’s two, there’s an outer ply and an inner ply.” said Mr. Lee, whose company makes and repairs airplane windows. Until 1994, he said, Lee Aerospace produced windows on the 737. “Either one of those windows is strong enough to hold the pressure.” 
   
   Each pane of an airplane window, he said, is designed to withstand two to four times the amount of pressure it would normally experience while in flight. 
   
   “That outer pane that cracked is generally the one that day in and day out is taking the pressure of the aircraft,” Mr. Lee said. The inner one “sits there and just prepares for that outer one to break. And when that outer one breaks, it takes over the pressure. It did a good job.” 
   
   He said it was understandable that passengers would worry when a window was damaged, but the window was made with such problems in mind. “When that outer pane fails, although it’s going to startle somebody,” it is not dangerous, he said. 
   
   Mr. Lee said he expected investigators to be able to determine what had happened fairly easily. 
   
   “They’ll be able to take that window and analyze it under a microscope and understand if it was fatigued over time or what the failure may have been,” he said.
target: – A Southwest Airlines plane flying from Chicago to New Jersey was forced to land in Cleveland on Wednesday after one of its windows cracked. The exit-aisle window cracked mid-flight, reports the New York Times, but the cabin never lost pressure as only one of the window's many plexiglass layers was affected. (You can see images here.) There were no reports of injuries after Flight 957 landed safely at Cleveland's Hopkins International Airport, and no emergency was declared. Aviation experts tell the AP the slightest defect or micro-crack in a plane window can cause cracks like this one. Airline consultant Robert Mann says windows are periodically polished to remove the formation of tiny cracks in the acrylic windows from exposure to chemicals and the sun's rays. "The flight landed uneventfully in Cleveland," Southwest said in a statement. "The aircraft has been taken out of service, and our local Cleveland Employees are working diligently to accommodate the 76 customers on a new aircraft to Newark." The incident comes two weeks after a Southwest Airlines plane made an emergency landing in Philadelphia after an engine explosion and a blown out window. A woman who was partly sucked out of that window was killed.