18 ms·

The Boeing 787 is now about nine years old. I wonder how much of this is operator proficiency triggering latent bugs (aka, "pilots got too good at pushing butto

by cbhl 8y ago

The Boeing 787 is now about nine years old. I wonder how much of this is operator proficiency triggering latent bugs (aka, "pilots got too good at pushing buttons quickly"). The bugs in the Therac 25 were only discovered after the machine had been in production for a while (you had to be typing "too quickly" in order to get the software to trigger the bug with the safety interlock).

Rooster61 8y ago
Considering the level of fly-by-wire that goes into airframes nowadays, I could certainly see such features added to older airframes through flight-software updates after they are already in service. I have no idea if that's how it's done in the field, though.
- bluGill 8y ago
  Software updates are done. However the manufacture has to recertify the airplane with the FAA first. This is expensive, requiring months of testing and a lot of paperwork. Each plane model getting the update needs to be re-certified, it isn't good enough to say that it works on this other model even if the planes are identical for purposes of that software.
deleted 8y ago
[deleted]
t0mas88 8y ago
It's not very typical for pilots to push buttons quickly. Especially not the thrustreversers and engine and flight controls. But it is entirely possible that nobody pulled the reversers while still airborne in 9 years, because it's a very strange thing to do. A bit like opening your car door while still driving 60 mph... Nobody does that in normal operation.
- NAHWheatCracker 8y ago
  A bit like opening your car door while still driving 60 mph... Nobody does that in normal operation. You don't open and shut a door when you notice it didn't fully close because you can hear the wind?
  - frogpelt 8y ago
    A better comparison might be putting the car in reverse at 60 MPH.
    - isostatic 8y ago
      You never missed a gear, thinking you were driving a 6 speed rather than a 5 speed?
      - stevehawk 8y ago
        No, but for as long as I've been driving manual cars they've had gates to prevent that very action. (1995)
        camtarn 8y ago
        Not mine (Honda Jazz). But you physically can't do it, as the reverse gear has no synchro and won't mesh unless stationary.
        jstanley 8y ago
        It can be done, but it's neither easy nor a good idea: https://youtube.com/watch?v=ARJENV0qGdY https://youtube.com/watch?v=ARJENV0qGdY You'd certainly struggle to do it by accident.
        dnate 8y ago
        it should make a loud grinding noise though,
      - ars 8y ago
- inferiorhuman 8y ago
  > But it is entirely possible that nobody pulled the reversers while still airborne in 9 years, because it's a very strange thing to do. That's overstating the case a bit. I'm 100% a layman here but I'd agree that the behavior seems like some sort of bug. But…… some planes (typically not commercial, although the Concord is one notable exception) call for reversers in flight under certain circumstances. Additionally there are definitely circumstances where a pilot might deliberately think reversers before touchdown are a good idea.
- sho 8y ago
  I've seen a number of videos on youtube of reversers been opened, if not fully spooled up, off the ground. It's not common but it does happen, especially in high cross-wind or otherwise iffy landings. Here's the first video I found but there are certainly others https://www.youtube.com/watch?v=-RO66a_nvus https://www.youtube.com/watch?v=-RO66a_nvus
noir_lord 8y ago
Make me think about could we use a robot to fuzz physical inputs.
- mhh__ 8y ago
  Probably not cost effective as opposed to either making the software more resilient or just letting some monkeys/interns loose in the cockpit and pressing everything (With some focused searches obviously)
  - noir_lord 8y ago
    I don't know, I suspect software resiliency is one of those "gets exponentially more expensive as you approach perfect" situations and a robot could bash inputs at speeds a human couldn't in thousands of orders, it would certainly let you test those weird code paths that blow up when they are never exercised until they are.
    - mhh__ 8y ago
      It does get exponentially more expensive, which is why you have to pick a certain level of ~perfection~ and then stop. Also, the robots would have to bash at the speed of a human: The point is to mimick human inputs not necessarily test every code path (Which you could do in software)
      - noir_lord 8y ago
        When testing resiliency software testing isn't the whole of the thing. I spent a lot of time at new job (well 18mths now) on making the software side more resilient, we still had a site wide outage of internet access and comms and internal systems because one of the women in the sales office unplugged a socket in the ingress comms cabinet to plug her hair straighteners in. Coincidentally my request to have physical access control on all the comms cabinets shot right up the list. The boundary layer between software and hardware itself has to be tested, the real world is a messy place :).
  - 8y ago
jzwinck 8y ago
The Ryanair booking website has several bugs exactly like what you describe. If you use it too quickly it won't sell you plane tickets. If you use it more slowly it works fine.
- aembleton 8y ago
  Probably to try and prevent bots

by cbhl 8y ago

Rooster61 8y ago

Considering the level of fly-by-wire that goes into airframes nowadays, I could certainly see such features added to older airframes through flight-software updates after they are already in service. I have no idea if that's how it's done in the field, though.

bluGill 8y ago
Software updates are done. However the manufacture has to recertify the airplane with the FAA first. This is expensive, requiring months of testing and a lot of paperwork. Each plane model getting the update needs to be re-certified, it isn't good enough to say that it works on this other model even if the planes are identical for purposes of that software.

deleted 8y ago

[deleted]

t0mas88 8y ago

It's not very typical for pilots to push buttons quickly. Especially not the thrustreversers and engine and flight controls. But it is entirely possible that nobody pulled the reversers while still airborne in 9 years, because it's a very strange thing to do. A bit like opening your car door while still driving 60 mph... Nobody does that in normal operation.

NAHWheatCracker 8y ago
A bit like opening your car door while still driving 60 mph... Nobody does that in normal operation. You don't open and shut a door when you notice it didn't fully close because you can hear the wind?
- frogpelt 8y ago
  A better comparison might be putting the car in reverse at 60 MPH.
  - isostatic 8y ago
    You never missed a gear, thinking you were driving a 6 speed rather than a 5 speed?
    - stevehawk 8y ago
      No, but for as long as I've been driving manual cars they've had gates to prevent that very action. (1995)
      - camtarn 8y ago
        Not mine (Honda Jazz). But you physically can't do it, as the reverse gear has no synchro and won't mesh unless stationary.
        jstanley 8y ago
        It can be done, but it's neither easy nor a good idea: https://youtube.com/watch?v=ARJENV0qGdY https://youtube.com/watch?v=ARJENV0qGdY You'd certainly struggle to do it by accident.
        dnate 8y ago
        it should make a loud grinding noise though,
    - ars 8y ago
inferiorhuman 8y ago
> But it is entirely possible that nobody pulled the reversers while still airborne in 9 years, because it's a very strange thing to do. That's overstating the case a bit. I'm 100% a layman here but I'd agree that the behavior seems like some sort of bug. But…… some planes (typically not commercial, although the Concord is one notable exception) call for reversers in flight under certain circumstances. Additionally there are definitely circumstances where a pilot might deliberately think reversers before touchdown are a good idea.
sho 8y ago
I've seen a number of videos on youtube of reversers been opened, if not fully spooled up, off the ground. It's not common but it does happen, especially in high cross-wind or otherwise iffy landings. Here's the first video I found but there are certainly others https://www.youtube.com/watch?v=-RO66a_nvus https://www.youtube.com/watch?v=-RO66a_nvus

noir_lord 8y ago

Make me think about could we use a robot to fuzz physical inputs.

mhh__ 8y ago
Probably not cost effective as opposed to either making the software more resilient or just letting some monkeys/interns loose in the cockpit and pressing everything (With some focused searches obviously)
- noir_lord 8y ago
  I don't know, I suspect software resiliency is one of those "gets exponentially more expensive as you approach perfect" situations and a robot could bash inputs at speeds a human couldn't in thousands of orders, it would certainly let you test those weird code paths that blow up when they are never exercised until they are.
  - mhh__ 8y ago
    It does get exponentially more expensive, which is why you have to pick a certain level of ~perfection~ and then stop. Also, the robots would have to bash at the speed of a human: The point is to mimick human inputs not necessarily test every code path (Which you could do in software)
    - noir_lord 8y ago
      When testing resiliency software testing isn't the whole of the thing. I spent a lot of time at new job (well 18mths now) on making the software side more resilient, we still had a site wide outage of internet access and comms and internal systems because one of the women in the sales office unplugged a socket in the ingress comms cabinet to plug her hair straighteners in. Coincidentally my request to have physical access control on all the comms cabinets shot right up the list. The boundary layer between software and hardware itself has to be tested, the real world is a messy place :).
- 8y ago

jzwinck 8y ago

The Ryanair booking website has several bugs exactly like what you describe. If you use it too quickly it won't sell you plane tickets. If you use it more slowly it works fine.

aembleton 8y ago
Probably to try and prevent bots