64 ms·

Ground Collision Avoidance System ‘Saves’ First F-16 in Syria

130 points by aerocapture 12y ago

themodelplumber 12y ago
This is really interesting. I found a PDF with some neat details and imagery describing the thinking that goes into Auto GCAS: http://www.sfte2013.com/files/78993619.pdf http://www.sfte2013.com/files/78993619.pdf I don't know if it's just coincidental, but a lot of the examples seem to be concerned with keeping jets from flying into mountains, as opposed to flying into level ground, which was the first thing that came into mind when I saw "Ground Collision."
- mik3y 12y ago
  Cool find! The pictures (and one slide) show an Android phone being used on a "Dryden drone", looks like it might have been a prototyping platform. Would love to see more detail about this. Edit: Ah, here's a senior project at CalPoly that was sponsored by NASA and looks related: http://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=1199&context=mesp http://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?articl...
  - termain 12y ago
    Quite impressive senior project. I know CalPoly aerospace does well with interacting with the industry and NASA.
- gonzo 12y ago
  I get "This site does not exist within the LDAP database." when I try that link. Mirror?
- aerocapture 12y ago
  Here's a recent video from NASA's Armstrong Flight Research Center discussing the Automatic Collision Avoidance Technology and the DROID UAV platform specifically. https://www.youtube.com/watch?v=XWx6-aK8Ick https://www.youtube.com/watch?v=XWx6-aK8Ick
kator 12y ago
I just finished the book "Skunk Works: A Personal Memoir of My Years of Lockheed" http://www.amazon.com/Skunk-Works-Personal-Memoir-Lockheed-ebook/dp/B00A2DIW3C# http://www.amazon.com/Skunk-Works-Personal-Memoir-Lockheed-e... It was a great book that almost feels like the pre-scrum manifesto applied to building aircraft.
- nether 12y ago
  All right, this has nothing to do with the Northrop/GD F-16.
  - kator 12y ago
    FTA: "Auto GCAS, which was developed by Lockheed Martin’s Skunk Works"
afterburner 12y ago
"According to the Air Force, 26% of aircraft losses and 75% of all F-16 fatalities are caused by such accidents." Wow.
- marvin 12y ago
  Keep in mind that jet fighter crashes are often survived by the pilot if he or she has the time to react and bail out. Many crashes are caused by technical malfunction or loss of control at altitudes where the pilot has plenty of time to react. However, if the pilot is still on board, ground collision at flight speed is almost universally fatal. Fighter pilots during ground attack or low-level dogfighting are always pushing the envelope both in aerodynamic/structural capability and maneuvering wrt. terrain hazards, so ground collision is a very serious safety hazard. Military pilots have much, much smaller margins of error than commercial or recreational pilots.
  - afterburner 12y ago
    Yes, the wow was more about the 26%.
  - konstruktor 12y ago
    The article specifically talks about controlled flight into terrain, which, by definition excludes malfunctions.
    - theoh 12y ago
      I think the point being made about malfunctions is that they are less likely to lead to fatalities than CFIT. This would explain the high percentage of fatalities caused by CFIT.
derwildemomo 12y ago
That's great. Maybe someone here can enlighten me as to why the systems, specifically TCAS and GPWS in modern civilian planes are only ever used to issue warnings/recommendations, but never take control? it would have at least prevented the überlingen mid air collision and probably some other CFIR incidents in the past years. I thought about this for a while and couldn't come up with a really good reason.
- neurotech1 12y ago
  Auto GCAS also used in cases of G-LOC (G-Induced Loss of Consciousness) which is practically unheard of in a civilian airliner that is able to land safely afterwards. Fighter aircraft frequently engage in maneuvers that are seconds away from hitting the ground (or water) if something goes wrong. überlingen was a tragic anomaly caused by multiple factors, the pilots knew they were on a collision course but due to the conflict between TCAS and ATC they collided. This possibility has been reduced by issuing a TCAS reversal if the other jet responds differently than expected.
- tiwfm2 12y ago
  Early TCAS versions did not even provide correctives, so systems that even provide RAs you could use for automatic corrections are relatively new. Give it (a lot of) time.
- ridgeguy 12y ago
  Might be product liability issues. Software malf may have completely different economic consequences in civilian vs. military environments.
- Perdition 12y ago
  Difficulty of international agreements, and the expense. Upgrading to fully autonomous systems adds a lot of cost but is only going to make a difference in a small number of incidents (civilian aircraft don't fly as low and fast as fighters, and civilian pilots aren't distracted by being shot at).
- hudibras 12y ago
  It's only a matter of time. My guess is that it'll happen within the next 30 years.
WalterBright 12y ago
Reminds me of a description of air combat where the pursued would dive, and then pull out at the last possible moment, hoping the pursuer would misjudge and pull out too late. One pulled out so low he raised dust on the ground. My father liked to attack ack-ack positions by diving vertically on them, as the gun crew obviously was reluctant to fire straight up. Of course, you gotta keep a real close eye on your altitude and airspeed doing that.
- thecopy 12y ago
  There was an incident (among many) between a Swedish figher and the Russian figher on Swedish territory maybe 20 years ago where the Russian was following the Swedish fighter. The Swedish planes being more sophisticated then the Russian fighters, the Swedish pilot went for the sea, straight bown. He pulled back when he knew his plane would make it, but the Russian figher jet could not handle the G's, broke and crashed into the sea killing the pilot.
- trhway 12y ago
  >misjudge and pull out too late Su-30 at airshow: https://www.youtube.com/watch?v=YcUvtnL5p4Y https://www.youtube.com/watch?v=YcUvtnL5p4Y
ForHackernews 12y ago
"a 5g pull" Yikes!
- Sharlin 12y ago
  That's a pretty run-of-the-mill acceleration as far as fighter maneuvers go. Momentary accelerations in excess of 10g are not unheard of and the use of an ejection seat exposes the pilot to 12g or even more.
  - Perdition 12y ago
    Yeah but ejecting is often career ending because of those G's.
    - toufka 12y ago
      I was curious how traumatic it can be. Went searching and found this abstract from a paper[1] studying ejections in the German Air Force from 1981-1997: "[86 ejections from 56 aircraft had an] overall success [(survival)] rate of 97.6%. Of all 85 participants, 12 (14%) were uninjured, 41 (48.2%) were slightly injured, and 30 (35.3%) were severely injured. Typical injuries were those of the spine and lower limbs. The most common severe injury was a vertebral fracture caused by ejection acceleration. This is followed by lower limb injuries received during the parachute landing fall." [1] http://www.ncbi.nlm.nih.gov/pubmed/10596782 http://www.ncbi.nlm.nih.gov/pubmed/10596782
throwaway8898 12y ago
hmm ... as a pilot and student of WW2 combat, I think this might be ok in peace-time, but definitely a problem in war time. - to avoid radar, you have to fly low - tree-top high - to save ammo, you have to shoot near ground-targets - can the software be fooled in mountainous terrain? - what about off-field landings? - Japan's most effective bombers were kamikaze, and American pilots also considered ramming other aircraft after their ammo ran out - if the software is wrong, does it roll inverted and pull down at 5G? how do you stop it?
- sharth 12y ago
  The article says that 1. The pilot is first notified that the system is about to take control. and 2. That the pilot can override the system at any time.
- jjwiseman 12y ago
  From http://www.aerotechnews.com/laafb/files/publications/ala_10082010A20.pdf http://www.aerotechnews.com/laafb/files/publications/ala_100..., it looks like it's designed to avoid "nuisance activations": “As Nils got down low, I could see dirt being kicked up off of the desert floor and no nuisance activations.”
  - mjmahone17 12y ago
    1,600 automatic avoidances in 141 hours of flight. Holy crap, that's a lot of "point it at the ground, hope you don't die". Unless they did something else?
    - mattmanser 12y ago
      Surely they just set the ground level to be higher?
- kelseyfrancis 12y ago
  Did you RTFA? Do you honestly believe these utterly basic questions you've posed after a few seconds of consideration never occurred to any Air Force or Lockheed or NASA personnel involved in building this system? Or are you just cynical enough to believe the Air Force isn't really concerned about the "war time" effectiveness of its _fighter_ planes?
dankohn1 12y ago
Can you imagine the testing rigor you would need for this sort of system, knowing that if you incorrectly engaged or steered the aircraft, you would be responsible for killing the pilot?
- ccleve 12y ago
  My thought exactly. Warning! Warning! NullPointerException! No, that's a contract I do not want.
  - iLoch 12y ago
    I remember reading somewhere that these guys get all the time they want to program these systems, and the environment is very relaxed - I suppose for this very reason.
    - curiously 12y ago
      Write one line of code everyday, make sure it's bug free. I wouldn't be surprised if they used functional programming and avoiding object orientated programming.
      - PhantomGremlin 12y ago
        Why wouldn't they be using Ada? That's exactly what is was developed for.[1] Does anybody know if Ada is still in use for writing new applications? [1] https://en.wikipedia.org/wiki/Ada_%28programming_language%29 https://en.wikipedia.org/wiki/Ada_%28programming_language%29
        mparlane 12y ago
        http://search.lockheedmartinjobs.com/ShowJob/Id/25009/Software-Engineer-ava,-C-,-ADA-Clearance-needed-MST-Manassas/ http://search.lockheedmartinjobs.com/ShowJob/Id/25009/Softwa...
        ObviousScience 12y ago
ricardonunez 12y ago
This is fascinating stuff. Does anybody know the whole cost of this system? I only was able to find a pdf and it says that the seed money was $2.5 millions. If anybody is interested here's the link: http://www.nasa.gov/sites/default/files/337112main_Auto-GCAS-NR-AFPS.pdf http://www.nasa.gov/sites/default/files/337112main_Auto-GCAS...
- boombip 12y ago
  I found this PDF: http://www.globalsecurity.org/military/library/budget/fy2015/usaf-peds/0207133f_7_pb_2015.pdf http://www.globalsecurity.org/military/library/budget/fy2015... that says it cost ~2 million to integrate in 2013.
kingkawn 12y ago
Why are we bombing Syria?
- rufustherag 12y ago
  Google 'isis' aalong with beheadings, rape, child slavery, sex slaves, burning people alive, burying people alive etc. Alternatively buy a newspaper from time to time.
  - kingkawn 12y ago
    Funny that you and many others got angry because I asked the question that you want to no longer have anyone ask. Is each bomb going to kill ISIS, or might it do more? Then "why are we bombing syria" never stops being a relevant question to ask, and never one that is fully answered until the answer becomes that we are not.
  - kingkawn 12y ago
    Also there are lots of horrible regimes and atrocities around the world at all times. The reason we are bombing this one likely has nothing to do with any of the above, and so remains a valid question.
- chrisbennet 12y ago
  Jordan is bombing Isis in Syria.
Animats 12y ago
The USAF finally went for that? It was first demonstrated in 1998, and has been used by the Swedish air force for years. Their slogan is "You can't fly any lower". Here's the 1998 writeup, copied from Aviation Leak: http://www.f-16.net/f-16_versions_article8.html http://www.f-16.net/f-16_versions_article8.html The technical paper: http://www.icas.org/ICAS_ARCHIVE/ICAS1998/PAPERS/182.PDF http://www.icas.org/ICAS_ARCHIVE/ICAS1998/PAPERS/182.PDF The actions this system takes are drastic. Roll rates to 180 degrees/sec to get to wings-level, then a 5G pull-up. The pilot's helmet may be banged against the canopy. It's so drastic because flying 150 feet off the ground in mountainous terrain is normal procedure for fighters. If the system has to act to avoid a collision, that action has to be very aggressive. Here's what it looks like to a pilot: https://www.youtube.com/watch?v=aPr2LWctwYQ https://www.youtube.com/watch?v=aPr2LWctwYQ Here, the pilot puts the plane into an insane bank and, as he says, "goes to sleep" and releases the controls.
- spyder 12y ago
  ... and here is a longer video from NASA about their development of collision avoidance system that can work for regular planes too: https://www.youtube.com/watch?v=XWx6-aK8Ick https://www.youtube.com/watch?v=XWx6-aK8Ick
  - Animats 12y ago
    That's so NASA PR. About 80% of the stuff in that video was not done by NASA. The F-16 auto-GCAS was a USAF/Swedish Air Force/Lockheed project. The NASA people are just reusing that technology on a model aircraft.
naz 12y ago
The Stuka had a slightly less sophisticated version of this in 1935: http://en.wikipedia.org/wiki/Junkers_Ju_87#Diving_procedure http://en.wikipedia.org/wiki/Junkers_Ju_87#Diving_procedure
- cbr 12y ago
  Significantly less, but still impressive for its purpose.

130 points by aerocapture 12y ago

This is really interesting. I found a PDF with some neat details and imagery describing the thinking that goes into Auto GCAS: http://www.sfte2013.com/files/78993619.pdf http://www.sfte2013.com/files/78993619.pdf I don't know if it's just coincidental, but a lot of the examples seem to be concerned with keeping jets from flying into mountains, as opposed to flying into level ground, which was the first thing that came into mind when I saw "Ground Collision."

mik3y 12y ago
Cool find! The pictures (and one slide) show an Android phone being used on a "Dryden drone", looks like it might have been a prototyping platform. Would love to see more detail about this. Edit: Ah, here's a senior project at CalPoly that was sponsored by NASA and looks related: http://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=1199&context=mesp http://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?articl...
- termain 12y ago
  Quite impressive senior project. I know CalPoly aerospace does well with interacting with the industry and NASA.
gonzo 12y ago
I get "This site does not exist within the LDAP database." when I try that link. Mirror?
aerocapture 12y ago
Here's a recent video from NASA's Armstrong Flight Research Center discussing the Automatic Collision Avoidance Technology and the DROID UAV platform specifically. https://www.youtube.com/watch?v=XWx6-aK8Ick https://www.youtube.com/watch?v=XWx6-aK8Ick

kator 12y ago

I just finished the book "Skunk Works: A Personal Memoir of My Years of Lockheed" http://www.amazon.com/Skunk-Works-Personal-Memoir-Lockheed-ebook/dp/B00A2DIW3C# http://www.amazon.com/Skunk-Works-Personal-Memoir-Lockheed-e... It was a great book that almost feels like the pre-scrum manifesto applied to building aircraft.

nether 12y ago
All right, this has nothing to do with the Northrop/GD F-16.
- kator 12y ago
  FTA: "Auto GCAS, which was developed by Lockheed Martin’s Skunk Works"

afterburner 12y ago

"According to the Air Force, 26% of aircraft losses and 75% of all F-16 fatalities are caused by such accidents." Wow.

marvin 12y ago
Keep in mind that jet fighter crashes are often survived by the pilot if he or she has the time to react and bail out. Many crashes are caused by technical malfunction or loss of control at altitudes where the pilot has plenty of time to react. However, if the pilot is still on board, ground collision at flight speed is almost universally fatal. Fighter pilots during ground attack or low-level dogfighting are always pushing the envelope both in aerodynamic/structural capability and maneuvering wrt. terrain hazards, so ground collision is a very serious safety hazard. Military pilots have much, much smaller margins of error than commercial or recreational pilots.
- afterburner 12y ago
  Yes, the wow was more about the 26%.
- konstruktor 12y ago
  The article specifically talks about controlled flight into terrain, which, by definition excludes malfunctions.
  - theoh 12y ago
    I think the point being made about malfunctions is that they are less likely to lead to fatalities than CFIT. This would explain the high percentage of fatalities caused by CFIT.

derwildemomo 12y ago

That's great. Maybe someone here can enlighten me as to why the systems, specifically TCAS and GPWS in modern civilian planes are only ever used to issue warnings/recommendations, but never take control? it would have at least prevented the überlingen mid air collision and probably some other CFIR incidents in the past years. I thought about this for a while and couldn't come up with a really good reason.

neurotech1 12y ago
Auto GCAS also used in cases of G-LOC (G-Induced Loss of Consciousness) which is practically unheard of in a civilian airliner that is able to land safely afterwards. Fighter aircraft frequently engage in maneuvers that are seconds away from hitting the ground (or water) if something goes wrong. überlingen was a tragic anomaly caused by multiple factors, the pilots knew they were on a collision course but due to the conflict between TCAS and ATC they collided. This possibility has been reduced by issuing a TCAS reversal if the other jet responds differently than expected.
tiwfm2 12y ago
Early TCAS versions did not even provide correctives, so systems that even provide RAs you could use for automatic corrections are relatively new. Give it (a lot of) time.
ridgeguy 12y ago
Might be product liability issues. Software malf may have completely different economic consequences in civilian vs. military environments.
Perdition 12y ago
Difficulty of international agreements, and the expense. Upgrading to fully autonomous systems adds a lot of cost but is only going to make a difference in a small number of incidents (civilian aircraft don't fly as low and fast as fighters, and civilian pilots aren't distracted by being shot at).
hudibras 12y ago
It's only a matter of time. My guess is that it'll happen within the next 30 years.

WalterBright 12y ago

Reminds me of a description of air combat where the pursued would dive, and then pull out at the last possible moment, hoping the pursuer would misjudge and pull out too late. One pulled out so low he raised dust on the ground. My father liked to attack ack-ack positions by diving vertically on them, as the gun crew obviously was reluctant to fire straight up. Of course, you gotta keep a real close eye on your altitude and airspeed doing that.

thecopy 12y ago
There was an incident (among many) between a Swedish figher and the Russian figher on Swedish territory maybe 20 years ago where the Russian was following the Swedish fighter. The Swedish planes being more sophisticated then the Russian fighters, the Swedish pilot went for the sea, straight bown. He pulled back when he knew his plane would make it, but the Russian figher jet could not handle the G's, broke and crashed into the sea killing the pilot.
trhway 12y ago
>misjudge and pull out too late Su-30 at airshow: https://www.youtube.com/watch?v=YcUvtnL5p4Y https://www.youtube.com/watch?v=YcUvtnL5p4Y

ForHackernews 12y ago

"a 5g pull" Yikes!

Sharlin 12y ago
That's a pretty run-of-the-mill acceleration as far as fighter maneuvers go. Momentary accelerations in excess of 10g are not unheard of and the use of an ejection seat exposes the pilot to 12g or even more.
- Perdition 12y ago
  Yeah but ejecting is often career ending because of those G's.
  - toufka 12y ago
    I was curious how traumatic it can be. Went searching and found this abstract from a paper[1] studying ejections in the German Air Force from 1981-1997: "[86 ejections from 56 aircraft had an] overall success [(survival)] rate of 97.6%. Of all 85 participants, 12 (14%) were uninjured, 41 (48.2%) were slightly injured, and 30 (35.3%) were severely injured. Typical injuries were those of the spine and lower limbs. The most common severe injury was a vertebral fracture caused by ejection acceleration. This is followed by lower limb injuries received during the parachute landing fall." [1] http://www.ncbi.nlm.nih.gov/pubmed/10596782 http://www.ncbi.nlm.nih.gov/pubmed/10596782

throwaway8898 12y ago

hmm ... as a pilot and student of WW2 combat, I think this might be ok in peace-time, but definitely a problem in war time. - to avoid radar, you have to fly low - tree-top high - to save ammo, you have to shoot near ground-targets - can the software be fooled in mountainous terrain? - what about off-field landings? - Japan's most effective bombers were kamikaze, and American pilots also considered ramming other aircraft after their ammo ran out - if the software is wrong, does it roll inverted and pull down at 5G? how do you stop it?

sharth 12y ago
The article says that 1. The pilot is first notified that the system is about to take control. and 2. That the pilot can override the system at any time.
jjwiseman 12y ago
From http://www.aerotechnews.com/laafb/files/publications/ala_10082010A20.pdf http://www.aerotechnews.com/laafb/files/publications/ala_100..., it looks like it's designed to avoid "nuisance activations": “As Nils got down low, I could see dirt being kicked up off of the desert floor and no nuisance activations.”
- mjmahone17 12y ago
  1,600 automatic avoidances in 141 hours of flight. Holy crap, that's a lot of "point it at the ground, hope you don't die". Unless they did something else?
  - mattmanser 12y ago
    Surely they just set the ground level to be higher?
kelseyfrancis 12y ago
Did you RTFA? Do you honestly believe these utterly basic questions you've posed after a few seconds of consideration never occurred to any Air Force or Lockheed or NASA personnel involved in building this system? Or are you just cynical enough to believe the Air Force isn't really concerned about the "war time" effectiveness of its _fighter_ planes?

dankohn1 12y ago

Can you imagine the testing rigor you would need for this sort of system, knowing that if you incorrectly engaged or steered the aircraft, you would be responsible for killing the pilot?

ccleve 12y ago
My thought exactly. Warning! Warning! NullPointerException! No, that's a contract I do not want.
- iLoch 12y ago
  I remember reading somewhere that these guys get all the time they want to program these systems, and the environment is very relaxed - I suppose for this very reason.
  - curiously 12y ago
    Write one line of code everyday, make sure it's bug free. I wouldn't be surprised if they used functional programming and avoiding object orientated programming.
    - PhantomGremlin 12y ago
      Why wouldn't they be using Ada? That's exactly what is was developed for.[1] Does anybody know if Ada is still in use for writing new applications? [1] https://en.wikipedia.org/wiki/Ada_%28programming_language%29 https://en.wikipedia.org/wiki/Ada_%28programming_language%29
      - mparlane 12y ago
        http://search.lockheedmartinjobs.com/ShowJob/Id/25009/Software-Engineer-ava,-C-,-ADA-Clearance-needed-MST-Manassas/ http://search.lockheedmartinjobs.com/ShowJob/Id/25009/Softwa...
      - ObviousScience 12y ago

ricardonunez 12y ago

This is fascinating stuff. Does anybody know the whole cost of this system? I only was able to find a pdf and it says that the seed money was $2.5 millions. If anybody is interested here's the link: http://www.nasa.gov/sites/default/files/337112main_Auto-GCAS-NR-AFPS.pdf http://www.nasa.gov/sites/default/files/337112main_Auto-GCAS...

boombip 12y ago
I found this PDF: http://www.globalsecurity.org/military/library/budget/fy2015/usaf-peds/0207133f_7_pb_2015.pdf http://www.globalsecurity.org/military/library/budget/fy2015... that says it cost ~2 million to integrate in 2013.

kingkawn 12y ago

Why are we bombing Syria?

rufustherag 12y ago
Google 'isis' aalong with beheadings, rape, child slavery, sex slaves, burning people alive, burying people alive etc. Alternatively buy a newspaper from time to time.
- kingkawn 12y ago
  Funny that you and many others got angry because I asked the question that you want to no longer have anyone ask. Is each bomb going to kill ISIS, or might it do more? Then "why are we bombing syria" never stops being a relevant question to ask, and never one that is fully answered until the answer becomes that we are not.
- kingkawn 12y ago
  Also there are lots of horrible regimes and atrocities around the world at all times. The reason we are bombing this one likely has nothing to do with any of the above, and so remains a valid question.
chrisbennet 12y ago
Jordan is bombing Isis in Syria.

Animats 12y ago

The USAF finally went for that? It was first demonstrated in 1998, and has been used by the Swedish air force for years. Their slogan is "You can't fly any lower". Here's the 1998 writeup, copied from Aviation Leak: http://www.f-16.net/f-16_versions_article8.html http://www.f-16.net/f-16_versions_article8.html The technical paper: http://www.icas.org/ICAS_ARCHIVE/ICAS1998/PAPERS/182.PDF http://www.icas.org/ICAS_ARCHIVE/ICAS1998/PAPERS/182.PDF The actions this system takes are drastic. Roll rates to 180 degrees/sec to get to wings-level, then a 5G pull-up. The pilot's helmet may be banged against the canopy. It's so drastic because flying 150 feet off the ground in mountainous terrain is normal procedure for fighters. If the system has to act to avoid a collision, that action has to be very aggressive. Here's what it looks like to a pilot: https://www.youtube.com/watch?v=aPr2LWctwYQ https://www.youtube.com/watch?v=aPr2LWctwYQ Here, the pilot puts the plane into an insane bank and, as he says, "goes to sleep" and releases the controls.

spyder 12y ago
... and here is a longer video from NASA about their development of collision avoidance system that can work for regular planes too: https://www.youtube.com/watch?v=XWx6-aK8Ick https://www.youtube.com/watch?v=XWx6-aK8Ick
- Animats 12y ago
  That's so NASA PR. About 80% of the stuff in that video was not done by NASA. The F-16 auto-GCAS was a USAF/Swedish Air Force/Lockheed project. The NASA people are just reusing that technology on a model aircraft.

naz 12y ago

The Stuka had a slightly less sophisticated version of this in 1935: http://en.wikipedia.org/wiki/Junkers_Ju_87#Diving_procedure http://en.wikipedia.org/wiki/Junkers_Ju_87#Diving_procedure

cbr 12y ago
Significantly less, but still impressive for its purpose.