A door plug area of an Alaska Airlines Boeing 737 Max 9 aircraft awaiting inspection is pictured with paneling removed at the airline's facilities at Seattle-Tacoma International Airport, Jan 10, 2024, in SeaTac, Wash, United States. (PHOTO / AP)

JAKARTA - Indonesia has allowed three Boeing 737 MAX 9 planes to fly again after grounding them, as they have different configurations from a jet that was forced to make an emergency landing in the United States on Jan 5, its transport ministry said on Thursday.

The transport ministry said the Lion Air planes had a "mid cabin emergency exit door type II" whereas the Alaska Airlines plane had a "mid exit door plug"

A cabin panel broke off a new Boeing 737 MAX 9 jet operated by Alaska Airlines in mid-flight, leading to the grounding of the model and inspections by the US Federal Aviation Administration (FAA).

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The incident occurred after take-off from Portland, Oregon, en route to Ontario, California, forcing pilots to turn back and land safely with all 171 passengers and six crew on board.

After grounding the three planes operated by Lion Air on Jan 6 and later inspecting them, Indonesia's transport ministry said it had allowed them to fly again since Jan 11.

Lion Air said in a statement the planes had different configurations from the Alaska Airline plane.

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The transport ministry said the Lion Air planes had a "mid cabin emergency exit door type II" whereas the Alaska Airlines plane had a "mid exit door plug".