Professional investigator concludes - "what's the fuss about?"

[Brojon]

A frozen turkey does not have metal parts. One errant screw, nut or bolt in a turbine engine can be catastrophic.
The anodized aluminum props on many smaller airplanes (including many turboprops) could easily be bent, throwing the prop off-balance, necessitating a shutdown of the engine.
A pitot tube and/or static port could be damaged, resulting in the loss of indicated airspeed and/or altitude and vertical speed.
I could go on, and on.
I am a FAA certificated airplane pilot, instrument and instructor rated. I also worked in aerospace for decades as a MSC to many projects including the Boeing 777.
Anybody who says drones pose no threat to airborne aircraft are simply full of it.

While respect your opinion I think that speculation is vastly overrated as a convincing argument - especially the part about errant screws and such. My dad was a crew chief in the USAF and he has shared plenty of stories with me on the stuff he's had to deal with - much of it from Vietnam where the aircraft endured some pretty extensive abuse.

 

[lisadoc]

Anybody who says drones pose no threat to airborne aircraft are simply full of it.

I don't believe anyone is advocating the position that drones pose no threat to airborne aircraft. However, the risk mitigation efforts should be equivalent to the actual risk posed to aircraft, not the perceived risk.

In safety terms, risk = probability x severity. Which means that in order to assess the overall risk to aircraft, we need to assess the probability of a strike with a drone occurring multiplied by the severity of that strike if it does occur. I would argue that the probability is likely very low, with minimal voluntary guidelines in place. The severity portion, for a large commercial aircraft, is also very low, since even if a strike occurs, likely it will cause little to no damage.

The issue is whether or not we mandate Draconian laws and regulations to control an industry that thus far, has posed little risk to the aviation sector (thereby killing the commercial benefit and economics of the drone industry). This is currently what the FAA and other regulators are faced with. If we wished to eliminate the risk entirely to commercial aircraft, the answer is simple: ban all drones and throw in jail anyone caught using one or manufacturing one. That will prevent any accidents from ever occurring. Or do we allow for the rational expansion and development of a large sector of the economy that ultimately may benefit society far more than we can imagine thus far (e.g. the Internet), with some reasonable guidelines? In fact, if you want to save more people's lives, ban cars. Or prevent them from driving within 5 miles of a school. Or limit their speed to no more than 20 miles/hour. You can do the same with a million other risky things that we take for granted on a daily basis.

Humans are terrible at personally assessing risk and even worse at enacting policy to deal with those risks. Politicians, and thereby the general public, have overreacted to the risk (and I mean that in the empirical sense) posed by small commercially-available drones and have pushed both the FAA and others to placate their fears. There are wise people within the FAA that realize this but they are also confronted by the political reality of being a federal agency ruled by the politicians and their budgets.

In fact, if you want to argue about the risk, as some have pointed out, the risk to small single-engine aircraft is far greater than the risk to large commercial aircraft. What we should be doing therefore is to ban drone flights near small, GA airports, rather than large, commercial airports. But again, this isn't what we're doing.

So far, reasoned discourse in the public and political forums has been in short supply and the end result is the desperate overreach by the FAA to control the backlash and the media to fan the flames.

 

[Brojon]

I don't believe anyone is advocating the position that drones pose no threat to airborne aircraft. However, the risk mitigation efforts should be equivalent to the actual risk posed to aircraft, not the perceived risk.
...

Perfectly stated - the whole thing.

 

[Marko9219]

While respect your opinion I think that speculation is vastly overrated as a convincing argument - especially the part about errant screws and such. My dad was a crew chief in the USAF and he has shared plenty of stories with me on the stuff he's had to deal with - much of it from Vietnam where the aircraft endured some pretty extensive abuse.

Overrated? Really? I personally saw a F-100 engine from an F-16 that was destroyed by a video cassette tape being dropped as the pilot was preparing to launch, and ingested by engine. A small, plastic video cassette. About the size and weight of the Mavic Pro. Go to YouTube and search for "F-18 FOD out". You'll see another jet engine destroyed something much, much smaller than a Mavic. Ever heard of a FOD walk? Ever done one? I have. Lots of them.

 

[Brojon]

Overrated? Really? I personally saw a F-100 engine from an F-16 that was destroyed by a video cassette tape being dropped as the pilot was preparing to launch, and ingested by engine. A small, plastic video cassette. About the size and weight of the Mavic Pro. Go to YouTube and search for "F-18 FOD out". You'll see another jet engine destroyed something much, much smaller than a Mavic. Ever heard of a FOD walk? Ever done one? I have. Lots of them.

You mean the one that clearly states they never ascertained what the object was?
My dad was absolutely the hardest on the airmen that didn't account for their tools. His #1 rule.
Also when aviation mechanics talk nuts and bolts we ain't referring to an 8-32.

PS: a videocassette isn't *anywhere* near the size and weight of a Mavic.

 

[Marko9219]

You mean the one that clearly states they never ascertained what the object was?
My dad was absolutely the hardest on the airmen that didn't account for their tools. His #1 rule.
Also when aviation mechanics talk nuts and bolts we ain't referring to an 8-32.

PS: a videocassette isn't *anywhere* near the size and weight of a Mavic.

So tell me how much difference in size and weight a VHS video cassette is from a Mavic? No matter what you say, after 30 years on an Air Force Base, I'm here to tell you that a Mavic presents a clear and present danger to a jet engine. Argue if you must, but as I type this, I'm within 200 ft of a whole BUNCH of active duty Air Force personnel including F-35 pilots at Hill AFB UT and

You mean the one that clearly states they never ascertained what the object was?
My dad was absolutely the hardest on the airmen that didn't account for their tools. His #1 rule.
Also when aviation mechanics talk nuts and bolts we ain't referring to an 8-32.

PS: a videocassette isn't *anywhere* near the size and weight of a Mavic.

So, as I was answering you just now, a squadron safety officer with the 34th FS here at HILL AFB just walked in. He's also a F-35 pilot. I brought him onto the conversation and he laughed. He said it's a HUGE topic of concern. I rest my case

 

[sar104]

So tell me how much difference in size and weight a VHS video cassette is from a Mavic? No matter what you say, after 30 years on an Air Force Base, I'm here to tell you that a Mavic presents a clear and present danger to a jet engine. Argue if you must, but as I type this, I'm within 200 ft of a whole BUNCH of active duty Air Force personnel including F-35 pilots at Hill AFB UT and
So, as I was answering you just now, a squadron safety officer with the 34th FS here at HILL AFB just walked in. He's also a F-35 pilot. I brought him onto the conversation and he laughed. He said it's a HUGE topic of concern. I rest my case

A typical video cassette weighs 200 - 300 g, depending on tape length etc. A Mavic weights about 750 g, and also contains metal parts. All of which supports your argument - if we are concerned about cassettes then we should certainly be concerned about Mavics, and Phantoms even more so. But you are trying to argue with an acute case of confirmation bias, so good luck with that.

 

[Marko9219]

... But you are trying to argue with an acute case of confirmation bias, so good luck with that.

That is until an actual F-35 pilot and safety officer weighed in on the topic, then I was arguing with expert opinion on my side.

 

[sar104]

That is until an actual F-35 pilot and safety officer weighed in on the topic, then I was arguing with expert opinion on my side.

No - you misunderstood - I agree with your argument. I should have said that you are arguing against an acute case of confirmation bias - that would have been clearer.

 

[Marko9219]

No - you misunderstood - I agree with your argument. I should have said that you are arguing against an acute case of confirmation bias - that would have been clearer.

Ahhh...Got it. Thanks. But, I agree, on this topic I am biased. Albeit, I am biased based on my 30 years on an Air Force base, time spent on a carrier flight wing and many, many friends that were military pilots, many of who now fly commercial jetliners. So, my bias is based on my past experiences and part of those experiences are seeing first-hand what a small object can do instantly to jet turbines. It was too funny actually, an hour ago as I was typing the above response and in walked Capt. Walz, the F-35 pilot. Talk about great timing! I said "Hey...Read this thread and tell me your thoughts about hobby drones and the threat to you guys." He actually laughed when he read it. He said they have briefings on this exact topic very frequently.

He literally said "They pose a huge threat if they are anywhere near our take-offs or landings."

On another very related threat, a good friend of mine was an A.F. instructor pilot at Luke AFB in T-38s. He had a bird come through the canopy and caused him to have to make an emergency landing from the back seat of the T-38.
How can people think a drone isn't a threat, when a bird...You know...All soft and fluffy and with hollow bones and all that, can do that to a jet canopy? He was afraid the student pilot had been seriously injured or killed, because he couldn't get him to respond at all for about 30 seconds. Turns out he was absolutely fine, but it scared him so badly he couldn't even voice a response to his instructor pilot for a bit.

 

[Brojon]

So tell me how much difference in size and weight a VHS video cassette is from a Mavic? No matter what you say, after 30 years on an Air Force Base, I'm here to tell you that a Mavic presents a clear and present danger to a jet engine. Argue if you must, but as I type this, I'm within 200 ft of a whole BUNCH of active duty Air Force personnel including F-35 pilots at Hill AFB UT and
So, as I was answering you just now, a squadron safety officer with the 34th FS here at HILL AFB just walked in. He's also a F-35 pilot. I brought him onto the conversation and he laughed. He said it's a HUGE topic of concern. I rest my case

I'm not sure what that means in the grand scheme of things. The whole reason we're discussing this is because a bunch of people have decided it is a "topic of concern".
So I'm to take an anecdotal response from some jockey as The Word? Sorry - I used to work on the range in Tonopah and "other" locations and I know firsthand what kind of men fly fighters.
Ask any of the jockeys that are old enough why they used to have Red Flag training - it was because they had their shorts handed to them in Vietnam from primitive tech. Seriously. Pilots are famous for being concerned with the wrong things. In Nam it was SAM sites that they worried about. What took them out in droves was a lowly triple A van using optical tracking. But oh man - those missiles were scary. SO scary they forgot about everything else.
This wasn't to run down pilots, I admire them no end - just pointing out they are humans too with flaws and predilections to their own beliefs not necessarily grounded in facts or experience.
You do seem convinced that a video cassette tape can take down any plane so I'll just leave you to ponder these test procedures by GE on their comnmercial engines.
Be sure to think hard (pun intended) about large balls of ice being shot into an engine at velocity. I'm thinking the Mavic might be a tad softer than that.

Watch GE Test Its Jet Engines by Putting Them Through Hell

 

[Brojon]

On another very related threat, a good friend of mine was an A.F. instructor pilot at Luke AFB in T-38s. He had a bird come through the canopy and caused him to have to make an emergency landing from the back seat of the T-38.

LOL- a T-38 *trainer*? Those things have one of the lightest canopies in the inventory. The whole plane is a lightweight for training in maneuvers.
The pilots in Iceland hated them with a passion and the canopies were always a large part of that with ravens the size of pitbulls flying around.

 

[sar104]

I'm not sure what that means in the grand scheme of things. The whole reason we're discussing this is because a bunch of people have decided it is a "topic of concern".
So I'm to take an anecdotal response from some jockey as The Word? Sorry - I used to work on the range in Tonopah and "other" locations and I know firsthand what kind of men fly fighters.
Ask any of the jockeys that are old enough why they used to have Red Flag training - it was because they had their shorts handed to them in Vietnam from primitive tech. Seriously. Pilots are famous for being concerned with the wrong things. In Nam it was SAM sites that they worried about. What took them out in droves was a lowly triple A van using optical tracking. But oh man - those missiles were scary. SO scary they forgot about everything else.
This wasn't to run down pilots, I admire them no end - just pointing out they are humans too with flaws and predilections to their own beliefs not necessarily grounded in facts or experience.
You do seem convinced that a video cassette tape can take down any plane so I'll just leave you to ponder these test procedures by GE on their comnmercial engines.
Be sure to think hard (pun intended) about large balls of ice being shot into an engine at velocity. I'm thinking the Mavic might be a tad softer than that.

Watch GE Test Its Jet Engines by Putting Them Through ****

At the strain rates involved the hardness of ice is not a significant factor and, in very high-speed impacts, such as with turbine blades, its behavior is largely hydrodynamic. That's not true of some of the component materials in a UAV. I'd suggest that you read more papers and watch fewer videos. The survivability of turbine blades under ice ingestion is a poor indicator of survivability with other materials.

So I'm to take an anecdotal response from some jockey as The Word? Sorry - I used to work on the range in Tonopah and "other" locations and I know firsthand what kind of men fly fighters.

So your anecdote is better than his? That's pretty funny.

 

[Marko9219]

At the strain rates involved the hardness of ice is not a significant factor and, in very high-speed impacts, such as with turbine blades, its behavior is largely hydrodynamic. That's not true of some of the component materials in a UAV. I'd suggest that you read more papers and watch fewer videos. The survivability of turbine blades under ice ingestion is a poor indicator of survivability with other materials.



So your anecdote is better than his? That's pretty funny.

... You do seem convinced that a video cassette tape can take down any plane so I'll just leave you to ponder these test procedures by GE on their comnmercial engines.
Be sure to think hard (pun intended) about large balls of ice being shot into an engine at velocity. I'm thinking the Mavic might be a tad softer than that.

Watch GE Test Its Jet Engines by Putting Them Through ****

you're danged right I'm convinced! I saw the destroyed engine with my own eyes. Had that jet been flying, it would have crashed. No doubt. That's not speculation, that's a fact. The engine did not survive ingesting a VHS cassette tape.

 

[Marko9219]

LOL- a T-38 *trainer*? Those things have one of the lightest canopies in the inventory. The whole plane is a lightweight for training in maneuvers.
The pilots in Iceland hated them with a passion and the canopies were always a large part of that with ravens the size of pitbulls flying around.

How does that reflect on the fact that a drone is a threat to an aircraft?

 

[Marko9219]

I'm not sure what that means in the grand scheme of things. The whole reason we're discussing this is because a bunch of people have decided it is a "topic of concern".
So I'm to take an anecdotal response from some jockey as The Word?

Anecdotal response by "some jockey"? That's pretty funny, considering that "jockey" is a wing safety officer.

 

[Lon Denard]

As an airforce brat, my dad served as an aircraft mechanic WWII, Korea and Vietnam and as a US Army veteran, 11B airborne, B4 cert, 16R Gunner and air defense/anti aircraft trainer for 3 systems 16C, 16S and 16P. I have some knowledge and experience in what it takes to down a plane. My dad would tell stories of what planes looked like after bombing runs and I know from first hand experience trying to down aircraft how hard it can be. I fully recognize that there are scenario that could cause a catastrophic failure during a drone/ aircraft collision. I'm stating that if such an occurrence was staged randomly 100 times you might get one compete engine failure. Maybe. I think it would have to be a perfect situation.

I personally stay away from airports anyway and wouldn't be opposed to an actual law that mandated that.I'm sure even airforce pilots would agree that the possibly of danger to them would be all but eliminated with a five mile rule.

 

[sar104]

As an airforce brat, my dad served as an aircraft mechanic WWII, Korea and Vietnam and as a US Army veteran, 11B airborne, B4 cert, 16R Gunner and air defense/anti aircraft trainer for 3 systems 16C, 16S and 16P. I have some knowledge and experience in what it takes to down a plane. My dad would tell stories of what planes looked like after bombing runs and I know from first hand experience trying to down aircraft how hard it can be. I fully recognize that there are scenario that could cause a catastrophic failure during a drone/ aircraft collision. I'm stating that if such an occurrence was staged randomly 100 times you might get one compete engine failure. Maybe. I think it would have to be a perfect situation.

I personally stay away from airports anyway and wouldn't be opposed to an actual law that mandated that.I'm sure even airforce pilots would agree that the possibly of danger to them would be all but eliminated with a five mile rule.

Probability is another thing altogether. There is no question that a UAV could hit an aircraft, any aircraft, and not bring it down. A lot depends on what gets impacted and so worst case is generally assumed - windshield, rotors, fan blades etc., But the probability naturally convolves the location of the impact and the outcome of the impact at that location. It is important, but if it is anything other than vanishingly small then it is going to be regarded as unacceptably high in the aviation world.

 

[Marko9219]

And lest we forget, let's remember that Air France flight 4590 (Concord SST) was brought down by a 200 gm piece of fod on the runway. 4 gigantic engines on a big airliner and a piece of metal that weighed a fourth of what the Mavic weighs. Oh... But that's different, right? The point is, small objects can, and have, taken out jets.

 

[Brojon]

And lest we forget, let's remember that Air France flight 4590 (Concord SST) was brought down by a 200 gm piece of fod on the runway. 4 gigantic engines on a big airliner and a piece of metal that weighed a fourth of what the Mavic weighs. Oh... But that's different, right? The point is, small objects can and have taken out a jet.

If you have an example make it a *pertinent* example

On July 25, 2000, an Air France Flight 4590 departing Charles de Gaulle International Airport ran over a piece of titanium debris from a Continental DC-10, shredding a tire and slamming rubber debris into the plane’s fuel tank. The subsequent leak and fire caused the Concorde to crash, killing 100 passengers, nine crewmembers, and four people on the ground.