8 ms·

I read elsewhere, from a reliable source that I can't find right now. that the mean time between reboots on 'mature' fighter planes is 8 hours and the F-35 is a

I read elsewhere, from a reliable source that I can't find right now. that the mean time between reboots on 'mature' fighter planes is 8 hours and the F-35 is at around 4 hours so far with plans to improve it. It was the first number that shocked me the most. EDIT: I found it: http://breakingdefense.com/2016/02/bogdan-predicts-f-35s-for-less-than-80m-engines-included/ http://breakingdefense.com/2016/02/bogdan-predicts-f-35s-for... The toughest problem the program is having is matching the timing of the aircraft’s fusion software with its sensors’ software. “As we add different radar modes and as we add different and capabilities to the DAS system and to the EOTS system, the timing is misaligned,” and then you have to reboot it. Bogdan said he’s aiming for eight to nine hours between such software failures when a radar or DAS or EOTS needs to be rebooted, which is what legacy aircraft boast. Right now they are at four to five hours between such events. “That’s not a good metric.” I don't understand a lot of that, but I think the fusion softwre refers to a unified UI for the pilot that merges information from the plane's very many sensors and presents it in a comprehensible way on one screen. Apparently pilots in older planes suffer from data overload and from watching many different screens at once - all while trying to fly a plane in combat. UI is reported to be a highly consequential improvement for the new plane.

raverbashing 11y ago
I can only imagine such sad state of affairs comes from extremely quirky requirements and very tight and crummy process (from TPS reports to worse) Yes, I can understand the problem is complicated, but come on.
jacquesm 11y ago
How many fighter plane flights last longer than 8 hours? It's a mean time after all, it could simply be a reflection of the length of the sortie.
- bluedino 11y ago
  Probably not a lot but it wouldn't be uncommon for an American plane to be in the air for 12+ hours with in-air refueling.
  - jacquesm 11y ago
    That mean time still leaves room for that doesn't it? (2 + 2 + 2 + 2 + 12) / 5 = 4. And so on. This whole statement is meaningless without more information about the distribution of lengths of flights.
  - mfoy_ 11y ago
    Forget fuel, and radar crashes... can you imaging flying a fighter jet for that long? The stress on the pilot must be insane.
    - kifler 11y ago
      Thats why they're fed a cocktail of amphetamines pre-flight for longer sorties.
  - neurotech1 11y ago
    It is relatively uncommon for a single-seat (& single-pilot) fighter jet to fly more than 8-9 hours. If they do, then AFI & OPNAV duty rules restrict how these flights are conducted (including combat ops) and how soon the crew can fly their next mission. Aircraft like the B-2 have two pilots and planned sleep periods. According to references, 13.5 hours [0] is the record for the F-16 combat mission, and this was actually a SEAD (Suppression of Enemy Air Defenses) mission in a single-seat F-16CJ. Similar missions in the EA-18G extended to 13+ hours with a single pilot, along with a WSO/EWO in the back seat. Various unofficial reports indicate F-16s do fly 14 hour ferry flights, but that is highly unusual. [0] http://www.f-16.net/f-16-news-article4413.html http://www.f-16.net/f-16-news-article4413.html
    - Grishnakh 11y ago
      What I'm wondering is how these fighter jet pilots deal with needing to go to the bathroom. 14 hours stuck in a tiny cockpit kinda makes it hard to relieve yourself...
      - cvwright 11y ago
- aries1980 11y ago
  Imagine the Falkland War's Vulcan march with hard reboots...
nerdy 11y ago
I have no experience with aviation, why do they need to be rebooted at all in less time than they can fly without refueling? It would seem with such a critical system the tolerance for rebooting would be exceptionally low. The F35 is not a dogfighter; does it have any meaningful capabilities while radar-blind?
- artmageddon 11y ago
  > why do they need to be rebooted at all in less time than they can fly without refueling? I don't know much about Navy / Air Force ops, but it's possible that a sortie may consist of taking off and returning to rearm / refuel without shutting down, which could easily span more than four hours. In addition, lots of fighter planes do refuel in mid-air, so the requirement is still very prevalent for the subsystem to remain functional.
  - nerdy 11y ago
    I'm actually curious what possible technical reason would prohibit them from running for 48+ hours (or indefinitely). IE some kind of garbage collection issue. I'm unaware of any reason they should ever have to be rebooted aside from software upgrades and curious why it might be necessary (technical reason). Unfortunately, from the article: "But the Air Force did not go into detail about when the instability in the radar system occurred..." Edit: It is mentioned elsewhere in this thread that it is a timing issue, see: http://breakingdefense.com/2016/02/bogdan-predicts-f-35s-for-less-than-80m-engines-included/ http://breakingdefense.com/2016/02/bogdan-predicts-f-35s-for...
    - vonmoltke 11y ago
      Have to shut the engines off at some point. Any vehicle "reboots" when you shut down the power.
  - vonmoltke 11y ago
    It is certainly possible, but not normal. Normally the engines are shut off during servicing and the aircraft is hooked up to a ground cart to provide limited systems functionality.
dokument 11y ago
Any clue to why it would take so long to reboot?
- shifter 11y ago
  The reboot itself is not the N hours figure, that's the interval between reboots.
agentx3r 11y ago
Likely refers to sensor fusion (https://en.wikipedia.org/wiki/Sensor_fusion https://en.wikipedia.org/wiki/Sensor_fusion), which is an algorithmic process. A 4-hour MTBF window (even for a subsystem) is terrifying considering modern vehicles like this are likely all fly-by-wire.
- hackuser 11y ago
  From the quote it appears that it's 4 hours between reboots of any subsystem, not the whole plane.
- toomuchtodo 11y ago
  Don't think of it as a failure. Think of it as a garbage collection pause at subsonic speeds.
  - frankydp 11y ago
    Spot on. This article should clarify what the radar reset that they are referring to is. Integer, origin, and timing resets are a function of radar tech, and are not specifically related to something like a system reboot. This would be something like restarting a process due to bad data getting into your process from a sensor and potentially leading to a bad result from a range or trajectory.
thearn4 11y ago
This is what happens when you have an entire industry (defense/general gov't services) that treats software development as a cost center instead of a profit center.
- wehadfun 11y ago
  I think it is time for the incumbents to be interrupted. Boring/Northrowup/... are fking up to much. Here is another defense industry f-up [0] [0] http://abcnews.go.com/US/jet-skier-broke-jfk-airports-security-wanted-caught/story?id=17550202 http://abcnews.go.com/US/jet-skier-broke-jfk-airports-securi...
mbell 11y ago
> The toughest problem the program is having is matching the timing of the aircraft’s fusion software with its sensors’ software I don't know if I'm interpreting that correctly but what I'm getting out of it is clock skew between sensors and the fusion system, which I assume to be referring to sensor fusion. That makes sense, analogous to a typical distributed systems issue. I would imagine the skew needed for the type of sensing they do is quite small. I doubt they can just toss an atomic clock on the plane :)
- Johnny555 11y ago
  I would imagine the skew needed for the type of sensing they do is quite small. I doubt they can just toss an atomic clock on the plane I don't think a single atomic clock would do it -- sounds like they'd need a high accuracy clock for each separate subsystem. But unlike distributed systems, it seems like an aircraft is small enough to have one clock that everyone uses - any idea why they don't do that? Single (or too much of a) point of failure? Disparate vendors can't agree on a standard? Too much extra wiring or other complexity?
  - vonmoltke 11y ago
    The standard way to do timing in a system like this is for each subsystem to run its own binary clock, with the main system sending period time-of-day messages to keep everything externally synchronized. In that sense, all the systems do have one clock. Many do not need to worry about wall clock time or synchronization, though.
- gherkin0 11y ago
  > I doubt they can just toss an atomic clock on the plane :) They totally could. Some atomic clocks are quite small. The one pictured on the below wiki page doesn't look that much bigger than a 3.5" hard drive. https://en.wikipedia.org/wiki/Rubidium_standard https://en.wikipedia.org/wiki/Rubidium_standard
  - scld 11y ago
    I wonder how something like that stands up to a gunfire vibration test.
saalweachter 11y ago
The thing I'm struggling with is, "Why does rebooting solve the problem?"

raverbashing 11y ago

I can only imagine such sad state of affairs comes from extremely quirky requirements and very tight and crummy process (from TPS reports to worse) Yes, I can understand the problem is complicated, but come on.

jacquesm 11y ago

How many fighter plane flights last longer than 8 hours? It's a mean time after all, it could simply be a reflection of the length of the sortie.

bluedino 11y ago
Probably not a lot but it wouldn't be uncommon for an American plane to be in the air for 12+ hours with in-air refueling.
- jacquesm 11y ago
  That mean time still leaves room for that doesn't it? (2 + 2 + 2 + 2 + 12) / 5 = 4. And so on. This whole statement is meaningless without more information about the distribution of lengths of flights.
- mfoy_ 11y ago
  Forget fuel, and radar crashes... can you imaging flying a fighter jet for that long? The stress on the pilot must be insane.
  - kifler 11y ago
    Thats why they're fed a cocktail of amphetamines pre-flight for longer sorties.
- neurotech1 11y ago
  It is relatively uncommon for a single-seat (& single-pilot) fighter jet to fly more than 8-9 hours. If they do, then AFI & OPNAV duty rules restrict how these flights are conducted (including combat ops) and how soon the crew can fly their next mission. Aircraft like the B-2 have two pilots and planned sleep periods. According to references, 13.5 hours [0] is the record for the F-16 combat mission, and this was actually a SEAD (Suppression of Enemy Air Defenses) mission in a single-seat F-16CJ. Similar missions in the EA-18G extended to 13+ hours with a single pilot, along with a WSO/EWO in the back seat. Various unofficial reports indicate F-16s do fly 14 hour ferry flights, but that is highly unusual. [0] http://www.f-16.net/f-16-news-article4413.html http://www.f-16.net/f-16-news-article4413.html
  - Grishnakh 11y ago
    What I'm wondering is how these fighter jet pilots deal with needing to go to the bathroom. 14 hours stuck in a tiny cockpit kinda makes it hard to relieve yourself...
    - cvwright 11y ago
aries1980 11y ago
Imagine the Falkland War's Vulcan march with hard reboots...

nerdy 11y ago

I have no experience with aviation, why do they need to be rebooted at all in less time than they can fly without refueling? It would seem with such a critical system the tolerance for rebooting would be exceptionally low. The F35 is not a dogfighter; does it have any meaningful capabilities while radar-blind?

artmageddon 11y ago
> why do they need to be rebooted at all in less time than they can fly without refueling? I don't know much about Navy / Air Force ops, but it's possible that a sortie may consist of taking off and returning to rearm / refuel without shutting down, which could easily span more than four hours. In addition, lots of fighter planes do refuel in mid-air, so the requirement is still very prevalent for the subsystem to remain functional.
- nerdy 11y ago
  I'm actually curious what possible technical reason would prohibit them from running for 48+ hours (or indefinitely). IE some kind of garbage collection issue. I'm unaware of any reason they should ever have to be rebooted aside from software upgrades and curious why it might be necessary (technical reason). Unfortunately, from the article: "But the Air Force did not go into detail about when the instability in the radar system occurred..." Edit: It is mentioned elsewhere in this thread that it is a timing issue, see: http://breakingdefense.com/2016/02/bogdan-predicts-f-35s-for-less-than-80m-engines-included/ http://breakingdefense.com/2016/02/bogdan-predicts-f-35s-for...
  - vonmoltke 11y ago
    Have to shut the engines off at some point. Any vehicle "reboots" when you shut down the power.
- vonmoltke 11y ago
  It is certainly possible, but not normal. Normally the engines are shut off during servicing and the aircraft is hooked up to a ground cart to provide limited systems functionality.

dokument 11y ago

Any clue to why it would take so long to reboot?

shifter 11y ago
The reboot itself is not the N hours figure, that's the interval between reboots.

agentx3r 11y ago

Likely refers to sensor fusion (https://en.wikipedia.org/wiki/Sensor_fusion https://en.wikipedia.org/wiki/Sensor_fusion), which is an algorithmic process. A 4-hour MTBF window (even for a subsystem) is terrifying considering modern vehicles like this are likely all fly-by-wire.

hackuser 11y ago
From the quote it appears that it's 4 hours between reboots of any subsystem, not the whole plane.
toomuchtodo 11y ago
Don't think of it as a failure. Think of it as a garbage collection pause at subsonic speeds.
- frankydp 11y ago
  Spot on. This article should clarify what the radar reset that they are referring to is. Integer, origin, and timing resets are a function of radar tech, and are not specifically related to something like a system reboot. This would be something like restarting a process due to bad data getting into your process from a sensor and potentially leading to a bad result from a range or trajectory.

thearn4 11y ago

This is what happens when you have an entire industry (defense/general gov't services) that treats software development as a cost center instead of a profit center.

wehadfun 11y ago
I think it is time for the incumbents to be interrupted. Boring/Northrowup/... are fking up to much. Here is another defense industry f-up [0] [0] http://abcnews.go.com/US/jet-skier-broke-jfk-airports-security-wanted-caught/story?id=17550202 http://abcnews.go.com/US/jet-skier-broke-jfk-airports-securi...

mbell 11y ago

> The toughest problem the program is having is matching the timing of the aircraft’s fusion software with its sensors’ software I don't know if I'm interpreting that correctly but what I'm getting out of it is clock skew between sensors and the fusion system, which I assume to be referring to sensor fusion. That makes sense, analogous to a typical distributed systems issue. I would imagine the skew needed for the type of sensing they do is quite small. I doubt they can just toss an atomic clock on the plane :)

Johnny555 11y ago
I would imagine the skew needed for the type of sensing they do is quite small. I doubt they can just toss an atomic clock on the plane I don't think a single atomic clock would do it -- sounds like they'd need a high accuracy clock for each separate subsystem. But unlike distributed systems, it seems like an aircraft is small enough to have one clock that everyone uses - any idea why they don't do that? Single (or too much of a) point of failure? Disparate vendors can't agree on a standard? Too much extra wiring or other complexity?
- vonmoltke 11y ago
  The standard way to do timing in a system like this is for each subsystem to run its own binary clock, with the main system sending period time-of-day messages to keep everything externally synchronized. In that sense, all the systems do have one clock. Many do not need to worry about wall clock time or synchronization, though.
gherkin0 11y ago
> I doubt they can just toss an atomic clock on the plane :) They totally could. Some atomic clocks are quite small. The one pictured on the below wiki page doesn't look that much bigger than a 3.5" hard drive. https://en.wikipedia.org/wiki/Rubidium_standard https://en.wikipedia.org/wiki/Rubidium_standard
- scld 11y ago
  I wonder how something like that stands up to a gunfire vibration test.

saalweachter 11y ago

The thing I'm struggling with is, "Why does rebooting solve the problem?"