(Reuters) -The U.S. Federal Aviation Administration barred Boeing (NYSE:BA) from expanding the production of its best-selling 737 MAX aircraft last week, after a mid-air cabin panel blowout forced an Alaska Airlines-operated MAX 9 to make an emergency landing.
The FAA launched a formal investigation into the 737 MAX 9, grounding the planes for safety checks and tightening oversight of Boeing itself on Jan. 12, after the Alaska Air (NYSE:ALK) incident.
The single-aisle 737 MAX, launched in 2011, is Boeing's cash cow and investors keep a close watch on its production and deliveries.
Boeing handed over 387 MAX aircraft in 2023 and had unfulfilled orders for 4,783 MAX jets, according to its website.
The MAX, which is powered by LEAP engines made by a joint venture between GE Aerospace and Safran (EPA:SAF), comes in four variants.
737 MAX 7
The MAX 7 is the smallest in the MAX family, with a maximum seating of 172 and a length of 35.56 meters. But at 3,800 nautical miles (4,373 miles), it has the longest range of the four variants.
The 737 MAX 7 has not been certified by the FAA yet and the recent crisis could delay certification, analysts have said.
Last week, Southwest Airlines (NYSE:LUV), the largest MAX 7 customer, said it had left the model out of its 2024 fleet plans due to the uncertainty around its approval. It previously expected the plane to be certified by April.
Boeing has 333 orders for the MAX 7, according to aviation analytics company Cirium.
737 MAX 8
The MAX 8, with a maximum seating capacity of 210, has a range of 3,500 nautical miles (4,028 miles) and is 39.52 meters long. It is the most popular MAX variant, with 1,179 aircraft in service and 1,973 on order, according to Cirium.
737 MAX 9
This model has been in the spotlight since the Jan. 5 Alaska Air incident.
The aircraft, which can seat a maximum of 220, has a range of 3,300 nautical miles (3,798 miles) and is 42.16 meters long.
There are 77 outstanding orders for the variant.
737 MAX 10
The 737-10 is the largest MAX plane, with a maximum seating capacity of 230. It is a competitor of Airbus's A321neo, which dominates the single-aisle narrowbody market.
The 737 MAX 10 can fly up to 3,100 nautical miles (3,567 miles) and measures 43.8 meters in length.
In November 2023, the model received the FAA's authorization for a type of inspection that allows FAA pilots to participate in flight testing to certify the plane for normal operations. Like the MAX 7, analysts say this variant's entry into service may be delayed by the ongoing crisis at Boeing.
Earlier on Monday, MAX 10 customer Ryanair said it was hopeful the model would be certified before the end of the year. Ryanair also told Boeing that if any U.S. customers refuse to take delivery of 737 MAX 10 aircraft, it would buy them "at the right price", executives said.
Boeing had 903 orders for the MAX 10 version, Cirium data showed.