US Federal Aviation Administration Orders Inspection of 9,300 Boeing 737 Aircraft After Defect Discovery

"Cabin Altitude Pressure Switch Defect Discovered"
Inspection of 9,300 Units Worldwide... Replacement Ordered if Abnormalities Occur

[Image source=AP Yonhap News]

[Asia Economy Reporter Hyunwoo Lee] The U.S. Federal Aviation Administration (FAA) has discovered some defects in Boeing's 737 aircraft models and has ordered a comprehensive inspection of over 9,300 Boeing 737 aircraft worldwide. If defects are found, repairs must be carried out.

On the 15th (local time), the FAA informed Boeing that a potential defect was found in the cabin altitude pressure switch across the entire Boeing 737 series. They ordered a full inspection and instructed that any aircraft found with defects must be repaired. There are 2,502 Boeing 737 aircraft registered in the United States, and 9,315 are operated worldwide.

The defect identified by the FAA involves an abnormality in the cabin altitude pressure switch. This switch is a warning device that activates when the aircraft ascends above 10,000 feet (approximately 3,050 meters), where oxygen levels can become dangerously low. In 2012, the FAA detected defects in this device across all Boeing 737 models and mandated the installation of two such switches per aircraft.

The FAA stated, "An inspection must be performed within 2,000 flight hours since the last inspection of the cabin altitude pressure switch, or within 2,000 total flight hours, and within 90 days from the effective date of this order." They also noted, "There is not yet sufficient information to determine the cause of this unexpected defect rate."

This switch defect issue began a thorough investigation after a flight function test in September last year revealed that two cabin altitude pressure switches failed to operate properly on three different 737 models. Initially, Boeing stated that there were no safety concerns while reviewing the switch defect. However, after further investigation and analysis, the FAA and Boeing announced in May that "the defect rate of the two switches is much higher than initially estimated, posing safety concerns."

According to major foreign media, this inspection and repair order is reportedly unrelated to the resumption of operations of the 737 Max model, which was involved in two previous crash accidents.