[the__alchemist]

Some loose thoughts:

Military aircraft cockpits sometimes don't have a great concept of "inside" and "outside", the way a cell, waterproof device, the aircraft's pressure seal etc do. If you drop something (FOD), there may not be a clearly defined boundary to where it can end up, or it may not be possible to see or get to it while strapped in etc. Rudder pedals, or the various mechanical and electrical connections around them, as indicated in the article, are a great example of this. If you can't find it, the AC may have to be grounded and thoroughly searched/panels removed etc.

Military avionics may be missing basic things that an EFB can help with, including maps, nav point and airport databases, weather info, ADSB info etc. EFBs are (IMO) a poor substitute due to the FOD concern here, the clunky touch screen interface (which you probably have to take gloves off for), the risk of getting locked out of important things like checklist and plates by BlackBerry, Foreflight licenses, passcode timers or other security layer etc.

You might have a jet that's 30 years old, just got retrofitted with a really nice radar etc, but the funding didn't make it through for a database, better displays/UI etc that would be better integrated with a jet, so you lean on the EFBs.

There are sometimes EFB mounts that can attach to a canopy via suction cup, clip onto various surfaces etc.

[FabHK]

Near-crash due to dropped pen: Air show plane went into nose dive after loose pen in cockpit jammed the controls

https://archive.is/YmIgB

[bbojan]

There was a helicopter crash in Canada due to an unrestrained tool bag: https://www.google.com/amp/s/beta.ctvnews.ca/local/ottawa/20...

And this one in Ireland due to a rag: https://www.irishtimes.com/news/helicopter-crash-caused-by-c...

[sph]

FOD? EFB? Any explanation of these acronyms for people outside the US military?

[kunwon1]

FOD = Foreign Objects and Debris EFB = Electronic Flight Bag. A flight bag, traditionally, contains charts and checklists. EFB means you have a device that contains those documents

20 years ago, I was an avionics technician on F-16 fighter jets in the USAF. We had 'FOD Walks' daily, which involved slowly walking down the flightline while staring at the ground, and picking up any loose objects

Even a tiny object, when ingested into a jet engine, can cause catastrophic damage. And F-16s have intakes very low to the ground, making them a much higher FOD risk.

The worst FOD events were when something broke. We used bit drivers to remove aircraft panels, and the bits were fairly standard screwdriver bits. Sometimes, one of those bits would shatter when applying force to remove a stubborn fastener. If that happens, you have to retrieve every single piece of metal. If you return your toolbox at the end of the day and it is missing anything that can't be accounted for, the entire flightline could be shut down while a search is carried out.

Dropping things in the cockpit could sometimes be much worse. If it drops down into a void left by removing a control panel, then it could potentially fall to the 'bottom' of the aircraft. If that happens, you'll be taking off all the panels in that vicinity, you'll have multiple people looking with flashlights, borescopes, etc.

If something is dropped but can't be found, that's probably a multi-day event that will involve some fairly high ranking people.

FOD was considered a serious threat, and a tiny piece of metal broken off of a tool could hinder operations for days at a time

[dredmorbius]

A reminder that the fatal crash of Air France Flight 4590, Concorde on takeoff from Charles de Gaulle airport, France, in 2000 was due to tire debris on the runway:

While taking off from Charles de Gaulle Airport, the aircraft ran over debris on the runway, causing a tyre to explode and disintegrate. Tyre fragments, launched upwards at great speed by the rapidly spinning wheel, violently struck the underside of the wing, damaging parts of the landing gear – thus preventing its retraction – and causing the integral fuel tank to rupture. Large amounts of fuel leaking from the rupture ignited, causing a loss of thrust in the left-hand-side engines 1 and 2. The aircraft lifted off, but the loss of thrust, high drag from the extended landing gear, and fire damage to the flight controls made it impossible to maintain control. The jet crashed into a hotel in nearby Gonesse two minutes after takeoff. All nine crew and 100 passengers on board were killed, as well as four people in the hotel. Six other people in the hotel were critically injured.

<https://en.wikipedia.org/wiki/Air_France_Flight_4590>

The debris was a metal strip "435 millimetres (17.1 in) long, 29 to 34 millimetres (1.1 to 1.3 in) wide, and 1.4 millimetres (0.055 in) thick", which had detached from a DC-10 which had taken off five minutes prior to the Concorde.

[kunwon1]

It is my understanding that, after the loss of the Concorde, one of the resultant advisories mentioned an automated FOD detection system, which did not exist at the time. There are now multiple companies selling such systems, using radar and optical sensors, and the FAA has advisories related to same [1] (pdf link)

The best possible outcome from a fatal crash is regulation that will prevent similar accidents in the future. I don't think automatic FOD detection is mandatory (at least, I can't find any evidence of a mandate) - but I assume that it will eventually be mandated, as costs come down.

[1] https://www.faa.gov/documentLibrary/media/Advisory_Circular/...

[bozhark]

Safety paved in blood

[dredmorbius]

As is so often the case.

"Why would anyone make a dumb rule about X?" can almost always be rephrased as "how many souls wrote this rule?"

Mercaptan-oderised natural gas is one example that stands out to me. The 300 souls of New London School, Texas, authored that one, in 1930.

[still_grokking]

At least those people take security really serous!

Compare to usual practice around IT…

Broken IT can in today's world directly or indirectly cause death of people. Some current examples:

https://www.bbc.com/news/world-australia-66130105

https://www.bloomberg.com/news/features/2023-04-20/tiktok-ef...

Still nobody cares!

[K0balt]

Im onboard with examining the social costs around technology, and business should be held accountable for the harm and costs that they externalize in the name of quarterlies. That is long overdue.

But to shoehorn it into the actionable and very direct context around aviation safety is a bit disingenuous. When a server crashes, the normal result is that it costs money. When an airliner crashes, hundreds of people die.

It doesn’t seem that they make a good metaphorical pair.

[still_grokking]

> When a server crashes, the normal result is that it costs money.

IT security isn't only about "not crashing servers".

> When an airliner crashes, hundreds of people die.

I've just showed examples where likely hundreds of people died because of missing impact evaluation on IT systems.

I think this is related.

As long as people don't see this nothing will change.

So yes, maybe my context switch is a little bit drastic. But this was the intend: To show similarities in outcomes and at the same time the hubris that things aren't taken seriously in the one case where they are taken very very serous in the other case, regardless of identical outcomes.

[K0balt]

I’m with you on the impact, especially going forward, of overall data infrastructure integrity. Failures in this realm will increasingly put the well being of people at stake.

My objection was more of the “catastrophic IT failure rarely causes direct physical harm, whereas catastrophic failures in aviation almost always results in fatalities” variety.

But yes, data infrastructure integrity is definitely an issue that must be treated as critical, and increasingly, as a life safety issue in some cases.

Although I feel like referencing self harm is not really in good faith here , because if that was a rational connection we should also be talking about treating interpersonal relations and good manners as a life safety issue in the same way that we regulate aviation.

[d1sxeyes]

Foreign Object Debris (shit that’s not supposed be there) and Electronic Flight Bag (an iPad or some other type of device which replaces paperwork)

[fullstop]

FOD = Foreign Object Debris

EFB = Electronic Flight ~Book~ Bag

edit: https://en.wikipedia.org/wiki/Electronic_flight_bag

It's bag, not book.

[foobarbecue]

The article says the B in EFB is "bag." Seemed strange to me, but I'm not familiar with the term. Do you think the article got it wrong?

[modernerd]

> The EFB gets its name from the traditional pilot's flight bag, which is typically a heavy (up to or over 18 kg or 40 lb) documents bag that pilots carry to the cockpit.

https://en.wikipedia.org/wiki/Electronic_flight_bag

[theolivenbaum]

It used to be an actual bag full of paper: https://en.m.wikipedia.org/wiki/Flight_bag

[theolivenbaum]

It used to be an actual bag full of paper https://en.m.wikipedia.org/wiki/Flight_bag

[PlatinumHarp]

No it's not wrong. The EFB replaces the contents of a traditional physical flight bag: binders full of charts, manuals for the plane, Airline documentation etc.

[fullstop]

I could be wrong, for sure.

[0ct4via]

Neither of these terms are unique to the US, or the military, or indeed the US military specifically.

FOD = foreign object debris... basically anything loose that can end up somewhere it doesn't and cause Foreign Object Damage - https://en.wikipedia.org/wiki/Foreign_object_damage

EFB = electronic flight bag ... basically using screens/displays (and more recently, the likes of iPads issued to Students / Flight Officers/ Pilots) which carry things like aircraft manuals, checklists, airport procedures, airport and aerodrome diagrams, etc. -- so called because they're designed to replace the "flight bag" that could be filled with over half a dozen (or more)heavy, chunky-as-heck books and binders containing the same information in paper form.

This becomes especially relevant when commercial aviation requires flight deck personnel to carry significant amounts of information like that with them, like train drivers can also have to do (rule books, locomotive / rolling stock manuals, track/depot diagrams, etc.)

Again, not remotely limited to the US military, or to the US or military in general -- these terms are common for those in aviation :)

[0ct4via]

In-cabin FOD can be things like loose pens (or even just pen lids/caps), iPads/books, etc. - which is why there are generally rules (admittedly more in the military, because they like that sort of thing) about ensuring things either meet certain FOD requirements/regulations (i.e. pens with screw-on caps, fitted in specific pen pockets, rather than one with a cap that could slide off, loose in a regular pocket), so ensure they don't end up interfering or blocking controls, etc.

As for outside the aircraft, FOD can cover anything from loose rubber / screws, etc. on the runway that could end up damaging the tires or being taken through the engines, to in-flight FOD risks like bird strikes and volcanic ash - which obviously are also foreign objects that risk damage to the aircraft.

[guestbest]

Funny thing is that these terms are just as familiar outside the air wing of the military as civilian aviation. If you used these terms with infantry, they’d just look blankly at you.

[dopamean]

FWIW these are aviation terms not military.

[pmarreck]

FOD = Foreign Object Damage, or in general, any object that could become a projectile when behind a jet or inhaled into it when in front of one.

EFB is actually defined in the article

[foobarbecue]

FOD is foreign object debris. EFB, "electronic flight bag" is discussed in the article.

[black6]

Foreign Object (Debris|Damage)

Electronic Flight Book

[mmaunder]

FOD? “EFBs are (IMO) a poor substitute due to the FOD concern here, the clunky touch screen interface (which you probably have to take gloves off for), the risk of getting locked out of important things like checklist and plates by BlackBerry, Foreflight licenses, passcode timers or other security layer etc.”???

This is basically just wrong. EFBs like ForeFlight are an incredibly rich and indispensable suite of tools from approach plates to a huge range of charts to log books to synthetic vision to adsb-in and much more. And operationally they’re very reliable and robust. I’m instrument rated, fly with a primary and backup iPad and have mine clamped to the yoke and it ain’t going anywhere.

ForeFlight licenses? What are you even talking about? In North America FF is almost a standard among GA pilots.

[civilitty]

The GP is talking about them in an operational military context, not a GA. I'm not too familiar with helicopters but see the L39 Alabtross or T38, for example. Even in trainer jets that are optimized for keeping students alive, the PIC can barely fit an iPad mini anywhere in the cockpit and there are tons of little places for things to fall and jam any number of mechanical linkages.

[scarier]

For perspective, the thing EFBs primarily replace is paper charts and approach plates, which are probably a worse FOD hazard due to how many different ones you have to use on a long flight. Most military pilots are trained to “dummy-cord” or otherwise secure anything that can become a FOD hazard inside the cockpit. There are plenty of products out there that let you strap a tablet to your leg at least as securely as a traditional kneeboard or IFR strap.

[rsynnott]

> If you can't find it, the AC may have to be grounded and thoroughly searched/panels removed etc.

_Why_ is this? Weight reduction or something? On the face of it it sounds like a design flaw.

[PuffinBlue]

I think the article and this mishap is an example of the reason why - if you can't find a dropped and loose object in the cockpit then you can't fly the aircraft because it may move in flight to somewhere where it can interfere with the controls.

In writing this answer it struck me you might be reading AC as Air Conditioning, instead of AirCraft, which I suppose could have lead to your question asking about weight reduction.

[lukeschlather]

Out of context I read AC as "alternating current" with "grounded" taking on a totally different meaning.

[dylan604]

Hopefully, we never need an aircraft to be fully grounded with a tethered cable. That'd be ridiculous. As a kid, I had a plane that was tethered and would only fly in circles. Oh, where the mind wanders on a Friday

[chipsa]

When planes are on the ground, they usually are fully grounded with a tethered cable for ESD reasons.

[Arrath]

Its standard to ground out a helicopter carrying a sling load before the load is touched/handled (it may even have a longer grounding cable that drags across the ground as it descends) because it can gather some pretty dangerous levels of charge.

[WastingMyTime89]

> Hopefully, we never need an aircraft to be fully grounded with a tethered cable.

That’s one way of landing an helicopter on a boat in a rough sea. It works surprisingly well.

[dylan604]

Speaking of grounding a helicopter, it reminded me of the Hunt For Red October scene of trying to get a person from a helicopter to a submarine. It always seemed like such a complicated something as opposed to just putting someone in the water to let a diver collect them, which is precisely what wound up happening anyways

[rsynnott]

Oh, sure, I get that if something gets lost you need to find it. My impression from the comment was that military cockpits were designed such that it was easier for stuff to get lost than it might be, tho, which is what I was curious about.

[bitwalker]

I worked on F-16 avionics (in aircraft maintenance, on the flightline), there are a lot of little nooks/holes/slots/gaps where small bits of FOD can fall and be incredibly difficult to extract, and the fear of that FOD causing a jam, flying around the cockpit, or getting wedged and causing unexpected wear on wiring harnesses and then shorting out (or worse, arcing) during flight was a _big_ deal. FOD in the cockpit was basically the worst thing that could happen during routine maintenance, because if you couldn't see it, and either couldn't get to it with a magnet (or the FOD wasn't metal), it might require pulling _a lot_ of stuff out of the cockpit before you could reach into the area where it fell. The worst case that could easily happen was having to have Egress come out and pull the ejection seat so you could get under it.

I always figured that all of those little gaps/etc. were due to a couple factors:

1.) the aircraft are constantly being upgraded/modified, so even if you designed the aircraft to be gap-free initially, there will inevitably be changes that introduce them. The cockpit itself is basically a frame with racks that hold all of the avionics, seat, etc.

2.) in conjunction with the above, ease of maintenance was somewhat important, so they tried to leave at least a little room to maneuver in the cockpit where possible (though there were plenty of places which were a nightmare to work regardless), but that comes at the cost of introducing areas where things can fall.

3.) some components have to be regularly removed and worked on outside the aircraft, or must be free of obstruction during flight, e.g. the ejection seat. So you end up with plenty of gaps where things can fall.

[HumblyTossed]

Why would one waste money (and weight) building a cockpit that was more than just utilitarian? It is a war machine which may get lost in war (or war practice).

[sitkack]

Sounds like a design flaw if there is so much open machinery that a dislodged part can jam everything up. Stuff comes apart.

A general engineering design principle is that things degrade smoothly so that there aren't abrupt changes in performance.

The aircraft controls should be protected such that foreign objects should have a low likelihood of jamming them. That there aren't things preventing someone from clearing any blockages and there aren't places where they could lever themselves in.

My car has a design flaw with respect to the floor mats and the accelerator pedal (its not a Toyota). Between how the lever arm and the pedal surface itself are design and the aftermarket floor mat, if the mat slides forward it can jam the accelerator down. These are the deep groove mats for catching mud and water. The designers didn't think of this, if the pivot point for the pedal was further up the firewall. The pedal also has a hard square edge. Both of those things are in general a design flaw for pedals. The NHTSA (National Highway Transportation Safety Administration) should and maybe they have (my car is old) the design of the pedal linkage and the shape of the pedal to reduce this kind of risk. The hooks for securing floor mats should also be standardized to help keep them in place.

The hard mount points for child seats are a great positive example of this.

[civilitty]

> The hard mount points for child seats are a great positive example of this.

You're comparing child seats built for the greatest common denominator to high tech war machines that were built on the principle of "kill or be killed" for the best funded and most advanced armed forces on Earth. Every kilo of paneling is another kilo that slows down the aircraft, reduces its range, and changes its balance/maneuverability.

Aircraft technicians are just expected not to drop pens and other crap in cockpits and engines on a regular basis. It's a completely different operational context.

[rsynnott]

One way to get lost, in war or otherwise, feels like someone dropping an iPad where no iPad should be. And these things aren't _generally_ exactly built on the cheap.

[dTal]

Avoiding the need to ground and strip the aircraft every time someone drops a pen seems pretty utilitarian.

[TylerE]

Military cockpits are a moving target in more ways than one. The cockpit of an aircraft like the B-52 is unrecognizable from when it was built.

[83]

Because while the FOD might not be an immediate problem, it could bounce around and get caught in a mechanical linkage causing a fatal crash, could be rubbing against wires causing a fatal crash, could start on fire (if it has lithium battery) causing a fatal crash, could cause a huge delay when maintenance finds a random part bouncing around later on and they don't know what it's from... you get the idea.

[ta123456789]

I thought the question is not why this is a problem, but rather why is it possible at all for a loose object to end up in the depths of the AC to cause problems. Is there some reason we cannot avoid this?

From a laymans perspective I think of a car, where dropping something small while driving is unlikely to cause problems in the machinery.

[bitwalker]

Cars have a lot of trim/seals/insulation/carpeting to reduce road noise and be aesthetically pleasing, and military aircraft cockpits don't care about either of those things, and are largely just a metal tube with racks on which all of the avionics and other cockpit equipment are mounted, with holes in a handful of places where wiring harnesses enter/exit the cockpit. All of that equipment is regularly worked on, removed/replaced, and so it is necessary that it be (relatively) easy to access and remove.

The equivalent would be like if you had to pull all of the instruments, electronics, and seats out of your car every 1000 miles, clean them up, replace faulty bits, and then put it all back again. All of the fancy trim, carpeting, etc., just makes that job harder, so you would probably want a car that doesn't have any of that, and is designed to make doing that kind of work easier, better still if you can avoid having to remove everything, and only have to remove the bits individually that need to be maintained. The down side of course, is that without all of the fancy trim and stuff, there would be gaps where things could fall and be hard to reach, and holes where wiring travels to the engine compartment/trunk/etc. Of course, FOD presents way less of a danger in a car than it does an aircraft, so you might not care if you drop something there, but aside from that, I think the analogy holds up.

[r3trohack3r]

Depending on your definition of “small” this is not true. I used to slide my flip flops off while driving until one got wedged under the break pedal and prevented me from breaking.

[HeyLaughingBoy]

Well, for starters, cars are designed to only travel in two dimensions, so that limits the problem quite a bit.

[maushu]

Because the missing device might cause something similar to this crash but instead with a internal mechanism. You really don't want loose stuff around moving mechanisms.

[awhow]

You don't want a screwdriver, or anything else, pressed up against a control rod or a rotating component.