It seems the Boeing 737 Max
The two deadly plane crashes were both caused by a software issue with the Max that led to uncontrollable nose dives. Another factor was the reaction of the pilots which was slower and less efficient than Boeing, and regulators, had expected. The F.A.A. and manufacturers will need to update assumptions to account for true pilot reactions.
December was a busy month for Boeing. Dennis A. Muilenburg, Boeing's then chief executive, was fired after he repeatedly made overly optimistic statements about the Max and alienated F.A.A. regulators. Boeing's stock has dropped 21% and tens of billions of charges may be brought against them related to the groundings. The F.A.A. requested that Boeing carry out an internal audit to find all problems and irregularities with the Max, and they did indeed find more problems.
They discovered previously unreported concerns about the wiring that controls the tail of the aircraft. Two bundles of wire may be too close together, increasing the probability of a short circuit which could lead to more deadly crashes. If Boeing finds that the problem is serious enough, 800 airplanes will need to be altered, but the company says it would be an easy fix.
Boeing informed the F.A.A. of the problem and has had internal dialogue discussing potential changes to the wiring system. Meanwhile, it's possible that nearly 7,000 of the Max's predecessor, the 737 NG planes, currently in service could have the same problem. A senior Boeing engineer told the New York Times that finding and fixing these sorts of problems is common across all airplane manufacturers.
Also under scrutiny is the Max's engine. CFM International, a partnership between General Electric and Safran and the manufacturer of the Max's engine, has reported that a part of the engine is vulnerable because of a weakness that could lead to the part shattering. The possibility that this part could fail is too remote for regulators to require a replacement, but they have requested the CFM inspects as many engines as possible.
A poor choice made in the manufacturing process of the 737 Max has also lead to a lack of protection against lightning strikes. In order to make the engine fit better in its housing, workers in the Boeing factory ground down a panel, inadvertently removing an insulating coating meant to prevent damage to the fuel tank and fuel lines of the plane from lightning strikes. The F.A.A. will require the lighting protection to be repaired before the planes will be allowed to fly.
Despite these problems, the Boeing 737 Max could still be approved to fly by this spring. Again, if the wiring is significant enough a problem, the fix would only take two hours per plane according to the company. Boeing says it's too soon to say whether or not changes will need to be made to the planes but that they will be working with the F.A.A. "to ensure a safe and compliant design." Boeing doesn't want to make unnecessary changes to the plane because of the possibility that damage could be done to the planes in the process.
International regulators are now traveling to Seattle to test the repairs on the Max's software meaning they feel Boeing is making enough progress to warrant a serious evaluation. A certification test flight is required before the plane is cleared to fly, and Government officials feel this could happen as soon as the end of the month. Some airlines have already scheduled flights on the Max for April and June. 5,000 planes have already been ordered by airlines around the world.
