US aviation regulators have ordered inspections of Boeing 737 NG aircraft after cracks were found on some planes.
“This issue does not affect any 737 Max airplanes or the P-8 Poseidon.”
The BBC has asked Boeing for more details about the cracks, and where they are located, but there has been no response so far.
Models of the 737 NG include 737-700, 737-800, and 737-900. Aeroflot, American Airlines, Ryanair and United Airlines are among the airlines listed as operators of the 737 NG model on Boeing’s website.
In its statement, the FAA said it would “instruct operators to conduct specific inspections, make any necessary repairs and to report their findings to the agency immediately”.
Boeing ground its entire global fleet of 737 Max aircraft in March this year following two fatal plane crashes.
The 737 Max has not flown commercially since an Ethiopian Airlines aircraft crashed shortly after take-off on 10 March, killing 157.
It followed a Lion Air crash on 28 October last year which killed 189. The FAA must decide if the plane is safe.