Putting Boeing's Dreamliner problems aside, the Federal Aviation Administration has taken issue with its 747s, due to the risk that cracks around a rear door could cause the planes to depressurize in flight. As a result, The FAA has proposed additional inspections.

The proposal calls for additional inspections every 3,000 flights on various models totaling about 150 planes. Each round of extra inspection is projected to cost $1.5 million, reported USA Today.

Boeing agreed with the proposal, which the company already had recommended to airlines and which FAA is publishing Wednesday in the Federal Register, according to USA Today.

"This (proposal) was prompted by multiple reports of cracking outside of the previous inspection areas," the FAA's 17-page announcement says. "We are issuing this (proposal) to detect and correct such cracks, which could cause damage to the adjacent body structure and could result in a rapid depressurization of the airplane," stated USA Today.

Though, no specific incidents were cited in the proposal that officials dub, "an air worthiness directive," it affects 747 models 100, 100B, 100B SUD, 200B, 200C, 200F 300, 400, 400D, 400F and SR. The added inspections are aimed at finding and fixing cracks in supports for the fuselage around main door five in the rear of the plane, according to USA Today.

Kate Bergman, a Boeing spokeswoman, says the company continuously monitors inspection reports to ensure the highest level of safety for the world's jetliners. She said the FAA proposal would mandate what Boeing already recommended to airlines.

"Boeing's recommendations are not binding on operators," Bergman says. "Only a regulator agency has the authority to require them. That is what the FAA's proposed rule would do," reported USA Today.

The newspaper further added that in January, the FAA ordered more inspections of 737s because sections of the roof came off two planes in flight, which depressurized the cabins and forced emergency landings.

But, those two incidents involved different joints rupturing, and the company says they are unrelated to the 747 problem, USA Today claimed.

"This in no way resembles the crown skin cracking experienced by some 737s," Bergman says, according to USA Today.