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People keep saying a lightweight craft under six pounds poses no threat to commercial aviation, but is that really true? I doubt a balloon with a circuit board

People keep saying a lightweight craft under six pounds poses no threat to commercial aviation, but is that really true? I doubt a balloon with a circuit board could cause an engine to fail, but there are lots of sensitive measurement devices, like a pitot tube, that I imagine could fail if a balloon hit it. (For reference, Aeroperu 603 was brought down by tape that wasn't removed from the plane.) I'm all about hobbyists hobbying, but it does seem like there should be at least some so of registration system so we know what people are launching into shared airspace.

ceejayoz 4y ago
> People keep saying a lightweight craft under six pounds poses no threat to commercial aviation, but is that really true? True enough for the extremely risk-averse FAA. > there are lots of sensitive measurement devices, like a pitot tube, that I imagine could fail if a balloon hit it. (For reference, Aeroperu 603 was brought down by tape that wasn't removed from the plane.) Tape over all of the multiply-redundant static ports on the aircraft. We don't treat tape as a critical threat to aircraft. The 737-MAX has three pitot tubes and six static ports, deliberately placed on both sides of the aircraft. (https://www.researchgate.net/figure/Boeing-737-NG-and-MAX-primary-air-data-sensors-with-processing-systems_fig4_343474935 https://www.researchgate.net/figure/Boeing-737-NG-and-MAX-pr...)
- deleted 4y ago
  [deleted]
- liketochill 4y ago
  But only 1 angle of attack sensor on some models …
  - Sakos 4y ago
    No, but that's fine, because Boeing needs to make money upselling carriers on redundancy.
  - fredoralive 4y ago
    No, the 737 Max has 2 AoA sensors, it just used a bizarre “only use one at a time and ignore the other” approach to (non) redundancy.
    - sigmoid10 4y ago
      If only that was the worst design issue with the 737 Max... It is astonishing how Boeing got away with that clusterfuck of a plane. All because they didn't wan't to invent a new body and beat Airbus to market.
petee 4y ago
https://udayton.edu/udri/news/18-09-13-risk-in-the-sky.php https://udayton.edu/udri/news/18-09-13-risk-in-the-sky.php Thats just a 2lb drone and it rips into the leading edge of a small craft, imagine at 500+ mph. Another good example is the Columbia disaster; it was just a piece of foam
- Dylan16807 4y ago
  > Another good example is the Columbia disaster; it was just a piece of foam Icy foam knocking a tile loose is not a critical problem for an airplane.
  - sbradford26 4y ago
    Yeah... your typical aircraft is not reaching Mach 20 where a hole would cause high temperatures leading to structural failure. Concerns about balloons and such can be valid but a comparison to Columbia is a big stretch.
    - petee 4y ago
      Clearly i should have added more words as I thought it was obvious I was just comparing projectile vs target; ie, just because an object is small or light doesn't mean it can't cause significant damage, and we don't have a lot of research into it. If it penetrates the wing, can it hit the fuel tank? And 6lb of metal hits different than 6lb of goose, depending on what it hits. Hail can destroy a radome.
      - kelnos 4y ago
        Fuel tanks are kevlar-lined nowadays, no? Certainly that doesn't make them invulnerable, but they can take quite a beating before they start leaking or worse.
  - bigtex88 4y ago
    That's not the point and you know it. Don't be pedantic. It doesn't help the conversation. The above poster is saying that even small problems can lead to catastrophic consequences in complicated machines.
akira2501 4y ago
The pitot and static are usually redundant. In the case of Aeroperu, it was being serviced, and so _all_ the static ports were taped over with duct tape. Which is an extremely unusual maintenance procedure and resulting failure mode, and in flight you wouldn't expect all of them to fail simultaneously, even after an impact with an foreign object. And critically, in their case, the ground radar warning system was working; however, due to all the other failures and alarms occurring on the flight deck, they did not notice or did not pay attention to this alarm. Modern aviation is so filled with redundancies and double checks that most disasters are the result of a long sequence of chained failures, and not due to a single piece of equipment becoming inoperative.
Thaxll 4y ago
A single bird can cause an engine to fail so...
- outworlder 4y ago
  Improbable unless it's a really enormous bird (or many large birds at one time). A chicken wouldn't be big enough. Bird ingestion would probably cause some damage that would have to be repaired, but jet engines are tested for this exact scenario. And engines are tested for large birds and both medium and small engine flocks. Sure, it _could_ happen with a single bird, but it probably won't. https://www.law.cornell.edu/cfr/text/14/33.76 https://www.law.cornell.edu/cfr/text/14/33.76
  - ikiris 4y ago
    I'm sure that Sully flight is much more confident that they didn't crash due to dual engine loss from bird strike thanks your comment.
    - antonjs 4y ago
      To pile on, the average weight of male Canadian Geese is > 8 pounds, which is higher than the largest 'large bird' that needs to be tested, and they travel in flocks. I think they worked out that each engine probably ingested two birds. At the time those engines were certified, the largest bird tested was 4 lbs and they only volleyed them into the outer area of the engine, not the core where the accident engines hit.[1] Now they have to send them into the 'most critical area' of the engine, but depending on engine size the largest bird tested could still be 4 or 6 lbs. [1] https://www.ntsb.gov/investigations/accidentreports/reports/aar1003.pdf#page=31 https://www.ntsb.gov/investigations/accidentreports/reports/...
      - detrites 4y ago
        By "tested", do you mean someone out there has the somewhat insane job of throwing actual birds into fully-powered jet engines? And I guess cleaning up afterward also?
barkerja 4y ago
All kinds of FOD (foreign object damage) can cause issue, regardless of its size or material. Look at what damage a small bird can deal, especially to a jet engine.
outworlder 4y ago
> People keep saying a lightweight craft under six pounds poses no threat to commercial aviation, but is that really true? Most likely. Even more so for lighter than air aircraft. An airliner traveling at Mach 0.8 would most most likely push this tiny thing out of the way like a feather even if it was in the flight path. Note that, regarding your pitot tube example, they are _pointy_. And heated. Assuming the balloon would even be hit and have its fabric intact, it would still be punched right through. Remember, 90000 pound aircraft traveling at Mach 0.8 (for an average 737) against a lighter than air balloon where the most rigid components are small circuit boards and thin solar panels. There isn't even an electronics case in most instances. Maybe engines would ingest it, but they wouldn't even notice.
- bloak 4y ago
  > Maybe engines would ingest it, but they wouldn't even notice. Someone once told me, but I can't remember whether it was an aviator or an ornithologist, that a bird with a metal ring on its leg could cause total destruction of a jet engine. Of course they don't attach metal rings to birds any more and haven't done so for a long time, and I'm not sure how big the risk was even with the chunkiest of old-fashioned rings. (What about a bird with an arrow stuck through it, I wonder? https://en.wikipedia.org/wiki/Pfeilstorch https://en.wikipedia.org/wiki/Pfeilstorch )
  - 4gotunameagain 4y ago
    Bird Ingestion Tests [0] are performed with a chicken gun™ in order to test the damage a bird would do to the engine. They don't put metal rings on them though ! https://www.youtube.com/watch?v=rSafRuLB0c0 https://www.youtube.com/watch?v=rSafRuLB0c0
- kulahan 4y ago
  I imagine it would destroy an engine on ingest, but that doesn't mean the plane goes down. They can fly with just one engine. It's hard, and they land ASAP, but nobody dies.
  - 4y ago
thrashh 4y ago
But people have been doing it for decades and most people didn’t even know about them so maybe everyone’s making a deal of a non-problem?
stickfigure 4y ago
"My club's hobby is testing how small/flimsy an object can be to bring down an airliner and kill hundreds of innocent people."
- BenjiWiebe 4y ago
  And so far the club hasn't managed to get even one person killed.
spoonfeeder006 4y ago
Collision with a bird can take down a fighter jet. So a circuit board can probably do that too If these have low radar signature, and they are below 60k feet then they could be a problem at least at night, and maybe during the day too
ssnistfajen 4y ago
Pitot tubes are rigid components with no moving parts involved in its mechanism. They aren't that fragile.
georgeg23 4y ago
> six pounds poses no threat to commercial aviation, but is that really true? It's because that's half the weight of a Canadian Goose.
- adastra22 4y ago
  Hitting a flock of birds can take out an engine tho.
  - kQq9oHeAz6wLLS 4y ago
    What about hitting half a goose?
    - neom 4y ago
      Here's some bird ingestion data for you from the certification of a GE90 Engine (large commercial airliner engine) "As part of the required certification testing, the GE90 successfully completed both the 2.5 and 8 lb. (1.13 and 3.63 kg) bird ingestion tests on the engine’s composite blades. In October 94, four 2.5 lb. birds were ingested with the engine running at speeds required to produce 85,000 lb. (377.8 kN) of thrust at takeoff on a hot day. There was no thrust loss and the engine responded to all throttle commands during the required 20 minutes of operation following the ingestion." https://www.easa.europa.eu/en/downloads/7799/en https://www.easa.europa.eu/en/downloads/7799/en https://www.kimerius.com/app/download/5781574315/The+GE90+-+An+introduction.pdf https://www.kimerius.com/app/download/5781574315/The+GE90+-+...
  - georgeg23 4y ago
    the point is birds don't need a license to fly, so balloons with that payload weight shouldn't either
  - tzs 4y ago
    Hitting a single bird can take down a plane. Here's some cockpit footage: https://www.youtube.com/watch?v=rNqU8jfAJMQ https://www.youtube.com/watch?v=rNqU8jfAJMQ Here's that didn't take down the plane, but made a big hole in the canopy spewing blood and guts all over the person in the back seat with the body hitting them in the shoulder. https://www.youtube.com/watch?v=XAn6yBJjC8g https://www.youtube.com/watch?v=XAn6yBJjC8g
tinglymintyfrsh 4y ago
There is no real problem here, and knee-jerk over-regulating won't help anything. That small drones and hobby R/C planes need fucking transponders in the US is bloody insane. Seeing aliens or Soviets in every birthday balloon that escapes into the wild blue yonder is ridiculous.
wkat4242 4y ago
Don't forget that they usually travel at 2x the flight ceiling of an airliner. The transition up and down is really quick. So the effective risk is low. And usually you can inform the authorities so they know where it is.

ceejayoz 4y ago

> People keep saying a lightweight craft under six pounds poses no threat to commercial aviation, but is that really true? True enough for the extremely risk-averse FAA. > there are lots of sensitive measurement devices, like a pitot tube, that I imagine could fail if a balloon hit it. (For reference, Aeroperu 603 was brought down by tape that wasn't removed from the plane.) Tape over all of the multiply-redundant static ports on the aircraft. We don't treat tape as a critical threat to aircraft. The 737-MAX has three pitot tubes and six static ports, deliberately placed on both sides of the aircraft. (https://www.researchgate.net/figure/Boeing-737-NG-and-MAX-primary-air-data-sensors-with-processing-systems_fig4_343474935 https://www.researchgate.net/figure/Boeing-737-NG-and-MAX-pr...)

deleted 4y ago
[deleted]
liketochill 4y ago
But only 1 angle of attack sensor on some models …
- Sakos 4y ago
  No, but that's fine, because Boeing needs to make money upselling carriers on redundancy.
- fredoralive 4y ago
  No, the 737 Max has 2 AoA sensors, it just used a bizarre “only use one at a time and ignore the other” approach to (non) redundancy.
  - sigmoid10 4y ago
    If only that was the worst design issue with the 737 Max... It is astonishing how Boeing got away with that clusterfuck of a plane. All because they didn't wan't to invent a new body and beat Airbus to market.

petee 4y ago

https://udayton.edu/udri/news/18-09-13-risk-in-the-sky.php https://udayton.edu/udri/news/18-09-13-risk-in-the-sky.php Thats just a 2lb drone and it rips into the leading edge of a small craft, imagine at 500+ mph. Another good example is the Columbia disaster; it was just a piece of foam

Dylan16807 4y ago
> Another good example is the Columbia disaster; it was just a piece of foam Icy foam knocking a tile loose is not a critical problem for an airplane.
- sbradford26 4y ago
  Yeah... your typical aircraft is not reaching Mach 20 where a hole would cause high temperatures leading to structural failure. Concerns about balloons and such can be valid but a comparison to Columbia is a big stretch.
  - petee 4y ago
    Clearly i should have added more words as I thought it was obvious I was just comparing projectile vs target; ie, just because an object is small or light doesn't mean it can't cause significant damage, and we don't have a lot of research into it. If it penetrates the wing, can it hit the fuel tank? And 6lb of metal hits different than 6lb of goose, depending on what it hits. Hail can destroy a radome.
    - kelnos 4y ago
      Fuel tanks are kevlar-lined nowadays, no? Certainly that doesn't make them invulnerable, but they can take quite a beating before they start leaking or worse.
- bigtex88 4y ago
  That's not the point and you know it. Don't be pedantic. It doesn't help the conversation. The above poster is saying that even small problems can lead to catastrophic consequences in complicated machines.

akira2501 4y ago

The pitot and static are usually redundant. In the case of Aeroperu, it was being serviced, and so _all_ the static ports were taped over with duct tape. Which is an extremely unusual maintenance procedure and resulting failure mode, and in flight you wouldn't expect all of them to fail simultaneously, even after an impact with an foreign object. And critically, in their case, the ground radar warning system was working; however, due to all the other failures and alarms occurring on the flight deck, they did not notice or did not pay attention to this alarm. Modern aviation is so filled with redundancies and double checks that most disasters are the result of a long sequence of chained failures, and not due to a single piece of equipment becoming inoperative.

Thaxll 4y ago

A single bird can cause an engine to fail so...

outworlder 4y ago
Improbable unless it's a really enormous bird (or many large birds at one time). A chicken wouldn't be big enough. Bird ingestion would probably cause some damage that would have to be repaired, but jet engines are tested for this exact scenario. And engines are tested for large birds and both medium and small engine flocks. Sure, it _could_ happen with a single bird, but it probably won't. https://www.law.cornell.edu/cfr/text/14/33.76 https://www.law.cornell.edu/cfr/text/14/33.76
- ikiris 4y ago
  I'm sure that Sully flight is much more confident that they didn't crash due to dual engine loss from bird strike thanks your comment.
  - antonjs 4y ago
    To pile on, the average weight of male Canadian Geese is > 8 pounds, which is higher than the largest 'large bird' that needs to be tested, and they travel in flocks. I think they worked out that each engine probably ingested two birds. At the time those engines were certified, the largest bird tested was 4 lbs and they only volleyed them into the outer area of the engine, not the core where the accident engines hit.[1] Now they have to send them into the 'most critical area' of the engine, but depending on engine size the largest bird tested could still be 4 or 6 lbs. [1] https://www.ntsb.gov/investigations/accidentreports/reports/aar1003.pdf#page=31 https://www.ntsb.gov/investigations/accidentreports/reports/...
    - detrites 4y ago
      By "tested", do you mean someone out there has the somewhat insane job of throwing actual birds into fully-powered jet engines? And I guess cleaning up afterward also?

barkerja 4y ago

All kinds of FOD (foreign object damage) can cause issue, regardless of its size or material. Look at what damage a small bird can deal, especially to a jet engine.

outworlder 4y ago

> People keep saying a lightweight craft under six pounds poses no threat to commercial aviation, but is that really true? Most likely. Even more so for lighter than air aircraft. An airliner traveling at Mach 0.8 would most most likely push this tiny thing out of the way like a feather even if it was in the flight path. Note that, regarding your pitot tube example, they are _pointy_. And heated. Assuming the balloon would even be hit and have its fabric intact, it would still be punched right through. Remember, 90000 pound aircraft traveling at Mach 0.8 (for an average 737) against a lighter than air balloon where the most rigid components are small circuit boards and thin solar panels. There isn't even an electronics case in most instances. Maybe engines would ingest it, but they wouldn't even notice.

bloak 4y ago
> Maybe engines would ingest it, but they wouldn't even notice. Someone once told me, but I can't remember whether it was an aviator or an ornithologist, that a bird with a metal ring on its leg could cause total destruction of a jet engine. Of course they don't attach metal rings to birds any more and haven't done so for a long time, and I'm not sure how big the risk was even with the chunkiest of old-fashioned rings. (What about a bird with an arrow stuck through it, I wonder? https://en.wikipedia.org/wiki/Pfeilstorch https://en.wikipedia.org/wiki/Pfeilstorch )
- 4gotunameagain 4y ago
  Bird Ingestion Tests [0] are performed with a chicken gun™ in order to test the damage a bird would do to the engine. They don't put metal rings on them though ! https://www.youtube.com/watch?v=rSafRuLB0c0 https://www.youtube.com/watch?v=rSafRuLB0c0
kulahan 4y ago
I imagine it would destroy an engine on ingest, but that doesn't mean the plane goes down. They can fly with just one engine. It's hard, and they land ASAP, but nobody dies.
- 4y ago

thrashh 4y ago

But people have been doing it for decades and most people didn’t even know about them so maybe everyone’s making a deal of a non-problem?

stickfigure 4y ago

"My club's hobby is testing how small/flimsy an object can be to bring down an airliner and kill hundreds of innocent people."

BenjiWiebe 4y ago
And so far the club hasn't managed to get even one person killed.

spoonfeeder006 4y ago

Collision with a bird can take down a fighter jet. So a circuit board can probably do that too If these have low radar signature, and they are below 60k feet then they could be a problem at least at night, and maybe during the day too

ssnistfajen 4y ago

Pitot tubes are rigid components with no moving parts involved in its mechanism. They aren't that fragile.

georgeg23 4y ago

> six pounds poses no threat to commercial aviation, but is that really true? It's because that's half the weight of a Canadian Goose.

adastra22 4y ago
Hitting a flock of birds can take out an engine tho.
- kQq9oHeAz6wLLS 4y ago
  What about hitting half a goose?
  - neom 4y ago
    Here's some bird ingestion data for you from the certification of a GE90 Engine (large commercial airliner engine) "As part of the required certification testing, the GE90 successfully completed both the 2.5 and 8 lb. (1.13 and 3.63 kg) bird ingestion tests on the engine’s composite blades. In October 94, four 2.5 lb. birds were ingested with the engine running at speeds required to produce 85,000 lb. (377.8 kN) of thrust at takeoff on a hot day. There was no thrust loss and the engine responded to all throttle commands during the required 20 minutes of operation following the ingestion." https://www.easa.europa.eu/en/downloads/7799/en https://www.easa.europa.eu/en/downloads/7799/en https://www.kimerius.com/app/download/5781574315/The+GE90+-+An+introduction.pdf https://www.kimerius.com/app/download/5781574315/The+GE90+-+...
- georgeg23 4y ago
  the point is birds don't need a license to fly, so balloons with that payload weight shouldn't either
- tzs 4y ago
  Hitting a single bird can take down a plane. Here's some cockpit footage: https://www.youtube.com/watch?v=rNqU8jfAJMQ https://www.youtube.com/watch?v=rNqU8jfAJMQ Here's that didn't take down the plane, but made a big hole in the canopy spewing blood and guts all over the person in the back seat with the body hitting them in the shoulder. https://www.youtube.com/watch?v=XAn6yBJjC8g https://www.youtube.com/watch?v=XAn6yBJjC8g

tinglymintyfrsh 4y ago

There is no real problem here, and knee-jerk over-regulating won't help anything. That small drones and hobby R/C planes need fucking transponders in the US is bloody insane. Seeing aliens or Soviets in every birthday balloon that escapes into the wild blue yonder is ridiculous.

wkat4242 4y ago

Don't forget that they usually travel at 2x the flight ceiling of an airliner. The transition up and down is really quick. So the effective risk is low. And usually you can inform the authorities so they know where it is.