Southwest Airlines and Boeing have asked federal officials for more time to inspect certain passenger jets for cracks in the frame. This will give manufacturers time to produces more spare parts.

Boeing, an aircraft maker, notified airlines last October that cracks were found in one of its 717 models. In May the Federal Aviation Administration proposed requiring inspections, and necessary repairs, to prevent that type of damage. The FAA said that theinspection order would apply to 129 planes registered in the country, and it estimated that inspections would be a minor expense. In contrast, it could cost up to $98,000 per plane to replace frame parts.

The damage might be caused by metal fatigue as a result of pressurizing the cabin after takeoff and depressurizing it after landing. In fact, the FAA has received reports of cracks in McDonnell Douglas MD-80-series planes. Those aircraft which have a similar design to the 717 in the area over the wings.

AirTran, a subsidiary of Southwest, uses most of the 717s flown in the U.S. That model of airplane, with only 117 seats in each jet, is smaller than 737 models. Last month, the company asked the FAA for more time to inspect and repair the planes because Boeing had no repair kits in stock and faced a 90-day reorder period. AirTran called the situation "unacceptable," and Southwest said it faced "an operational and economical impact" if planes were forced to stay on the ground. Therefore, Southwest requested that the FAA to postpone inspections until Boeing builds up its stock of repair kits and replacement parts.

According to the MSNBC website, "Boeing asked the FAA for up to 90 more days to review its October service bulletin after learning that cracks were found on a second 717 that had flown even fewer flights than the jet that prompted the first notice.The operators of the planes were not identified."