United Airlines has grounded at least 46 of its 79 Boeing 737 Max 9s after an Alaska Airlines jet of the same model suffered a serious in-flight pressurisation failure on 5 January.
That incident, which left a gaping hole in the side of the Alaska jet but did not seriously injure passengers or crew, has also prompted the Federal Aviation Administration to ground some 737 Max 9s.
“United has temporarily suspended service on select Boeing 737 Max 9 aircraft to conduct an inspection required by the FAA. We are working directly with impacted customers to find them alternative travel options,” Chicago-based United says.
The airline adds that 33 of its 79 Max 9s “have already received the necessary inspection that is required by the FAA”. The grounding forced United to cancel about 60 flights on 6 January.
The FAA has not yet publicly issued its grounding order but said on 6 January that such a measure is coming, in the form of an emergency airworthiness directive.
“The FAA will order the temporary grounding of certain Boeing 737 Max 9 aircraft operated by US airlines or in US territories,” it says.
The FAA’s order will require airlines to inspect jets at specified cycles, with inspections expected to take 4-8h each. The FAA says 171 Max 9s will be affected by the order, but it remains unclear how many will need to be grounded.
The issue appears limited to 737 Max 9s equipped with door “plugs” over mid-cabin emergency exits. While Max 9s can carry 220 passengers, aircraft fitted with fewer seats may not need, per regulations, the full complement of emergency exits. Airlines sometimes plug mid-cabin exits, which can save weight.
Airlines globally operate 215 in-service 737 Max 9s, according to Cirium data. It is unclear how many are equipped with emergency door plugs.
Several Max 9 operators, including Aeromexico, Copa Airlines and Turkish Airlines, did not respond to questions about the impact to their fleets.
| Globally, 11 airlines operate 215 737 Max 9s | |
|---|---|
| Aeromexico | 19 |
| Air Tanzania | 1 |
| Alaska Airlines | 65 |
| Copa Airlines | 29 |
| Corendon Dutch Airlines | 2 |
| flydubai | 3 |
| Icelandair | 4 |
| Lion Air | 3 |
| SCAT | 5 |
| Turkish Airlines | 5 |
| United Airlines | 79 |
| Total | 215 |
| Source: Cirium fleets data | |
Operators of other 737 Max variants, including Southwest Airlines and Canada’s WestJet, say their operations are unaffected.
Southwest says it does not operate Max 9s – only Max 8s – and that its jets “do not have the exit door plug involved in the Friday evening incident”.
Likewise, WestJet says its Max 8 fleet “does not have the same door in question”.
The Alaska incident happened shortly after the jet took off from Portland on the evening 5 January, headed to Ontario, California. As it ascended, an emergency exit door “plug” apparently blew out, leaving a hole in the side of the fuselage. The pilots safely returned to Portland.
