Stop us if you've heard this before: Boeing's working on 737 Max software fixes for autopilot, stabilization bugs
- Reference: 1586393023
- News link: https://www.theregister.co.uk/2020/04/09/boeing_737_max_software_fixes/
- Source link:
According to Reuters, Boeing is working on the updates as part of its efforts to get the 737 Max certified as safe to fly again by American authorities.
Two 737 Max passenger jets crashed in 2018 and 2019 killing 346 people total. A software system called MCAS – introduced to compensate for the effects of fitting engines larger than previously used by the 737 family – is suspected to be the cause, combined with faulty sensor readings and virtually non-existent pilot training for the feature.
Since then, Boeing has been battling to get the Max aircraft updated, tested, and approved for use. That has meant putting its systems through their paces again, which has turned up [1]various [2]weaknesses that need fixing.
To be clear, it is said by Boeing that these two bugs, involving the autopilot and stabilization, are new and not related to the faulty MCAS system, which is also being updated during the re-certification process.
The newswire [3]reported this week that one of the bugs "involves hypothetical faults in the flight control computer microprocessor, which could potentially lead to a loss of control known as a runaway stabilizer.” That's a fancy way of saying the nose is pointed down at the ground, which is not good news. The aircraft manufacturer has [4]previously run into microprocessor lock-ups in its 737 Max software.
Boeing 787s must be turned off and on every 51 days to prevent 'misleading data' being shown to pilots [5]READ MORE
The second software fix Boeing is reportedly working on is a fix for a flaw that could “potentially lead to disengagement of the autopilot feature during final approach.”
While this sounds alarming, “final approach” in aviation terms means the final couple of minutes of flight when the airplane is lined up with the runway and steadily descending. All the pilot has to do is take over from a known steady state, something they already do anyway on final approach in clear weather during daylight; a premature autopilot disengagement merely means the pilot takes over at, say, 3,000ft instead of 1,000ft.
It does, however, have implications for automatic landings in bad weather and at night. So-called Category III auto landings rely on the autopilot flying the entire final approach until the aircraft is immediately above or even on the runway; an autopilot failure could cause a stressful, costly, and time-wasting aborted landing.
Interestingly, Boeing told the newswire it doesn’t expect the current in-progress fixes to affect its projected mid-year return-to-service date for the Max. This appears not to take into account the coronavirus-inspired shutdown of the world’s economy, which has halted more or less everything across the West except the supply of food, medication, and hospital treatment, or thereabouts.
In January Boeing discovered that getting the two onboard flight control computers to talk to each other (they used to operate independently, with no hot standby for the active unit as is implemented on the rival Airbus A320 design) [6]caused a problem with power-on monitoring systems.
Sales for the whole of Boeing [7]dropped to historic lows in January as a direct result of the Max fiasco, showing that software development really does make all the difference. ®
Sponsored: [8]Choosing A Low-Code Vendor
[1] https://www.theregister.co.uk/2019/08/02/737_max_cosmic_bit_flipping_test/
[2] https://www.theregister.co.uk/2020/01/17/boeing_737_flaw/
[3] https://www.reuters.com/article/us-boeing-737max-software/boeing-making-new-737-max-software-updates-to-address-computer-issue-idUSKBN21P3K3
[4] https://www.theregister.co.uk/2019/06/27/boeing_737_max_control_bug_found/
[5] https://www.theregister.co.uk/2020/04/02/boeing_787_power_cycle_51_days_stale_data/
[6] https://www.theregister.co.uk/2020/01/17/boeing_737_flaw/
[7] https://www.theregister.co.uk/2020/01/15/boeing_sales_slump_after_737_max_omnishambles/
[8] https://go.theregister.co.uk/tl/1936/-8579/choosing-a-low-code-vendor?td=wptl1936
Re: autopilot disengagement during final approach
Since it's first Starliner test in December failed to reach the ISS due to runaway thrusters caused by software errors and they had to schedule another uncrewed test after additional software problems were found, I'd bet on three.
P.S. It has to be a bad omen when my spell check "corrected" uncre'wed to unscrewed.
so people are going to pay money to get on a 737 max?
mine's a helicopter ->
So not like they're just bodging anything together in a frantic attempt to get this thing that's costing billions of dollars every month it's not flying in the air again?
Independent bug-gery
"these two bugs [...[ are new and not related to the faulty MCAS system"
Well, *there's* a comfort!
There will be a hundreds or even thousands of second hand aircraft going very cheap next year after many airlines implode in the next few months
Bin It
Surely with the massive downturn that aviation is suffering and the abysmal publicity that Boeing have received for this rushed bodge job of an aircraft; commissioned in haste to compete with the Airbus NEO family just binning it would be the best option?
Due to recent events there are tens of thousands of aircraft mothballed at airfields around the world many belonging to airlines that will not emerge from this crisis. This will cause a glut of cheap aircraft to enter the market at a time when fuel costs are lower than they have been for years and with depressed global economies unlikely to recover soon will most likely stay low.
The biggest selling point of these new aircraft is the better operational efficiency - but with low global fuel prices this is far less of an issue for airlines with tight balance sheets and little capital available for expensive new aircraft.
That is before you consider the PR damage these aircraft will do to airlines. Traditionally a new fleet is a marketing coup for airlines. I can't think of many who would try and market this typhoid Mary of aviation.
Boeing should take the short term pain, kill the project and actually design a new, safer modern aircraft that doesn't rely on electronic tricks to overcome design restrictions inherent in legacy designs such as this 1960's era aircraft.
It's not the bugs in their software that are the problem. It's the bug in their software development process. How was an aircraft that was the product of such a process ever certified to fly? Don't the regulators look at the process?
autopilot disengagement during final approach
So does it tell you? Or does it silently go away while you're waiting for it to level out? That could get rough.
Also "runaway stabilizer" is short for "elevator goes to full-up or full-down" which is about as fatal as it gets.
I wonder how many issues the Boeing capsule is going to have on its next flight to the ISS... any bets?