On 5 January 2024 the left door plug, a panel that closes an unused mid-cabin emergency exit opening, separated from an Alaska Airlines Boeing 737-9 as it climbed through about 14,830 ft after departing Portland. The cabin depressurised, the aircraft returned to land, and seven passengers and one flight attendant received minor injuries (National Transportation Safety Board [NTSB], 2024). In Indonesia, the Directorate General of Civil Aviation temporarily halted operation of three Lion Air Boeing 737-9 MAX aircraft from 6 January 2024 while it coordinated with the FAA, Boeing and the airline. Lion Air said its aircraft use an active mid-cabin emergency exit rather than a door plug (Republika, 2024).
In early March 2024 the FAA announced the results of a six-week audit of Boeing and its fuselage supplier, which found non-compliance in manufacturing process control, parts handling and storage, and product control (Rose & Lewis, 2024). This case study looks at the event from a quality management perspective, based on the NTSB preliminary report. The final cause has not been determined, and the preliminary findings may change.
The Reported Event
The door plug is held against upward movement by four bolts. The damage patterns on the fittings and the absence of contact damage around the bolt holes indicate that all four bolts were missing before the plug moved off its stop pads (NTSB, 2024).
Manufacturing records show the fuselage arrived at Boeing's Renton factory on 31 August 2023. On 1 September 2023 a non-conformance record was raised for five damaged rivets on the frame forward of the left door plug. Replacing them required opening the plug, which meant removing the four retaining bolts. The rivets were replaced to engineering requirements on 19 September 2023. A photo shared between Boeing team members that evening, while they discussed restoring the interior, shows the plug closed with no bolts in the three visible locations; the fourth was hidden by insulation. The NTSB was still establishing which documents authorised opening and closing the plug, and found no evidence that it had been opened after the aircraft left the factory (NTSB, 2024).
Identified Factors
At the end of February 2024, an expert panel set up under United States aviation safety legislation delivered 27 findings and 53 recommendations on Boeing's safety culture. It observed a disconnect between senior management and the rest of the organisation on safety culture. Employees were confused about which reporting channel to use, distrusted the anonymity of the reporting programme, and preferred to raise issues directly with their managers (Section 103 Expert Panel, 2024). The FAA then gave Boeing 90 days to produce a plan to fix its quality problems (Rose & Lewis, 2024).
Analysis Against ISO 9001
ISO 9001:2015 requires production under controlled conditions with adequate documented information (clause 8.5.1), identification and traceability of outputs (clause 8.5.2), and verification of conformity whenever nonconforming outputs are corrected (clause 8.7) (International Organization for Standardization [ISO], 2015).
Our reading is that the rivet nonconformance itself was recorded and closed properly. The gap lay in the side work needed to fix it: the removal of another component that, on the preliminary evidence, left no record forcing it to be reinstalled and checked. Verification under clause 8.7 was aimed at the rivets, not at the door plug that was opened along the way. The panel's finding on confusing reporting channels suggests that procedural gaps of this kind are also harder to surface from the shop floor. This assessment rests on a preliminary report and may change once the final report is published.
Lessons for Factories
Rework that requires disassembly happens in many plants, from vehicle assembly to steel fabrication. Steps worth taking:
- Treat every disassembly for rework as a job with its own record, listing the parts removed and signed off when they are refitted (ISO, 2015).
- Set an independent inspection hold point before an area is closed up by insulation, panels or interior trim.
- Link each nonconformance record to all the follow-on work needed to close it.
- Provide one clear reporting channel and give feedback to those who report (Section 103 Expert Panel, 2024).
How Nusa Safety Helps
Nusa Safety helps companies design integrated ISO management systems and test how they work in practice through an ISO Gap Assessment and Internal Audit, including the control of rework and nonconformance. Work procedures and disassembly instructions can be developed through SOP and Technical Guidelines Development, and quality teams can practise root cause analysis in Incident Investigation and RCA.
This article is general information and not legal or professional advice for any specific case.
References
- International Organization for Standardization. (2015). Quality management systems - Requirements (ISO Standard No. 9001:2015). https://www.iso.org/standard/62085.html
- National Transportation Safety Board. (2024). Aviation investigation preliminary report: Alaska Airlines flight 1282, Boeing 737-9, N704AL (Report No. DCA24MA063). https://www.ntsb.gov/investigations/Documents/DCA24MA063%20Preliminary%20report.pdf
- Republika. (2024, January 9). Tiga pesawatnya dilarang terbang sementara, Lion Air pastikan operasional tak terganggu [Three of its aircraft temporarily grounded, Lion Air says operations unaffected]. Republika Online. https://ekonomi.republika.co.id/berita/s6yqze370/tiga-pesawatnya-dilarang-terbang-sementara-lion-air-pastikan-operasionaltak-terganggu
- Rose, J., & Lewis, R. (2024, March 4). FAA audit faults Boeing for 'multiple instances' of quality control shortcomings. NPR. https://www.npr.org/2024/03/04/1235826355/faa-audit-boeing-737-max-8-9-quality-control-failures
- Section 103 Expert Panel. (2024). Section 103 Organization Designation Authorizations (ODA) for transport airplanes expert panel review report: Final report. Federal Aviation Administration. https://www.faa.gov/newsroom/Sec103_ExpertPanelReview_Report_Final.pdf
