Made in USA: the boeing 737 cannot fly by using an intel 286 processor.

The software update required by the Boeing 737-MAX overloads the plane’s processor, preventing it from executing other vital instructions.

Boeing still cannot certify its 737 MAX aircraft after the two accidents that occurred a few months ago. Recently it was discovered that the software update that would solve the main fault cannot be executed smoothly and saturates the flight control computer.

During an examination administered by the United States Federal Aviation Administration (FAA), a pilot discovered a delay in executing a crucial step to stabilize the plane. At the end of the simulation, FAA staff determined that it was not possible to quickly and easily follow the Boeing emergency procedure to regain control of the plane.

All along, The New York Times reported that the problem is related to the speed of the processor found in the flight control computer (FCC). The failure of the Boeing 737 MAX is linked to the MCAS system, which is responsible for preventing the loss of the plane, and the software update that corrects it saturates one of the two chips that control the aircraft.

  • Boeing uses an eighties processor.

According to Moon of Alabama, the Boeing 737 MAX’s flight control computer has two CPUs that operate independently. These processors are Intel 80286 models with a maximum speed of 8 MHz, marketed between 1982 and 1991.

Peter Lemme, who worked as a flight control engineer at Boeing, said the plane’s computer executes up to 11 different instructions. The software design follows a very strict process that involves the use of special tools and a high level of optimization. Despite that, and that other manufacturers have produced similar chips that reach 25 MHz, the computer seems to be at the limit and the upgrade to the MCAS ends up overloading it, jeopardizing the execution of other instructions on the aircraft.

  • Why don’t they install a new chip?

The processors that control flight computers have a different lifetime than those found in our desktops or mobile devices. On an airplane, a processor is not measured in terms of power, but in reliability, and the Intel 80286 are error free.
Airplanes use the Fly-by-Wire (FBW), a system adopted by commercial airlines during the eighties in which standard flight keys are replaced with an electronic interface that works with the help of a computer.

The cockpit controls are converted into signals that are transmitted by cables and the flight control computer determines how the actuator moves on each of the control surfaces to provide the appropriate response.
Changing a component of the aircraft requires a new certification.

The software is programmed for the hardware, so changing the chip for another is not so simple. The programs that run on the computer are linked to the chip by a part number. Boeing cannot simply change the processor to a state-of-the-art one, as there are strict procedures that must be followed.

If Boeing wanted to replace a hardware component, it would have to pay for a new certification, perform tests involving hundreds of hours and receive approval from the authorities – in this case the FAA – with a certification that allows it to put its aircraft in the air.

In contrast, time and money are two concepts that today’s airlines cannot sacrifice.

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