Urban Air Mobility

It is further away than most people will tell you. 

Everyone sees the electric quad-copters, like DJI and such, and wishes they could ride on one. It seems so simple, just scale it up, and it can carry you, and a friend. Easy enough to fly, it will be fantastic, they go fast, no congestion in the sky, life is good. Lets do it!

Wow, there is a lotta money being spent on these vehicles, and not just from dreamers and hobbyists, but real live aerospace companies. Bell, Airbus and Boeing are all looking at the space, and at least throwing out drawings of stuff that might work. To be honest, you'd be silly to not be looking at this space, just in case.

What few people are saying, though, these little multi-copters that do vertical take-off and landing are not going to be main stream. If you can't afford to fly around in a helicopter today, you will not be able to fly in one of the passenger carrying multi-copters either. The cost will be similar when all is said and done, to flying in a modern helicopter.

Right now the batteries are the limiting factor. Even with a DJI or other "drone" type multi-copter it takes at least twice as long to charge the battery as the flight was. A 15 minute flight will take about 30-45 minutes to charge the battery for the next 15 minute flight. If you are Uber or some other air taxi service, this will kill the economic model right away. Every vehicle will spend over 2/3 of it's time charging between flights. Swapping battery packs may be an option, since the operator can have multiple packs charging at each station, but that will preclude landing in your neighborhood.

The multi-copters are noisy! People complain about jet noise around airports, so they don't live near any. Imagine you neighbor flying to work at 5:30AM everyday in one of these multi-copters. You will be up at 5:30AM yourself, and might as well go to work, you are up anyway. Having dozens of these flying over a venue you are at will certainly be annoying, plus think of the congestion that may occur for concerts and sporting events. Yup, it will be like the roads, with vehicles flying in to pick up passengers, blocking the vehicles with passengers trying to leave. With 3 or 4 pads near a arena will certainly be a limitation.

There is talk about putting pads on top of buildings, or at least high up. Winds are usually stronger higher up. Near the ground you might only have a 10kt wind, but up 20 stories (200ft) the winds may be 30-40kts. There will be turbulence for sure, but imagine the up and down drafts around buildings, and each landing and takeoff will be quite treacherous. Bad weather will be a whole other challenge, with heavy snow or ice storms, these vehicles won't be flying at all.

The multi-copters have multiple single points of failure. If a single motor fails on a quad-copter, the vehicle is coming down, the other three motors will not keep the craft flying. A hex or octa-copter will survive a single engine failure, but will probably not be able to complete the mission. Motors are electro-mechanical devices, they fail in different ways (bad bearings, broken wires, etc). Electronics fail, sensors fail, batteries fail. There is only so much redundancy that can be added to the vehicle to make it safe enough.

(Helicopters have many single points of failure as well, but there are usually ways to at least get the aircraft on the ground safely when any of them fail. An example is fuel exhaustion, when the motor(s) quit, the rotors can store energy. The pilot can pitch the craft down, such that the rotor is collecting energy from the movement through the air, that just before touching down, the aircraft can use that energy to slow the craft down and land soft enough-autorotation).

The propellers on the multi-copters are typically fixed pitch light weight affairs. Being fixed pitch means they are optimized for one realm of flight, typically for creating lift (forward motion, is more lift in the rear propellers, than the front ones). Should an engine fail, they have no mass to store energy, and will probably spin the wrong way in descent to be used for autorotation. Being light weight, they can be damaged easily by foreign objects, including birds, rocks, hail, trees, and people.

Commercial certification

Five years is very optimistic certification timelines people are pushing today for these urban air vehicles. If people where flying in these vehicles everyday, even experimentally, I could see maybe something could get pushed through in 5 years. As things are, maybe there is a Chinese company that is occasionally flying with people semi-regularly.

The FAA, EASA and the other regulating bodies will not let one of these vehicles get certified until it has proven capable through rigorous testing. That includes off normal operations, high winds, poor weather, and broken systems. It will take years of testing to get one of these vehicles certified to carry paying passengers.

Plan B

As a pilot you are always taught to look ahead, and consider your options. If an engine fails, where will I go, if a bird crashed through the windshield what will I do. If another aircraft is near me how do I avoid it, etc. The multi-copter pilot or automation will need to consider all of these things as well.

The vertical takeoff/vertical landing craft will need a plan B for the vertical part. While the vehicle is between 20 and 75 feet off the ground, no parachute system will save the occupants. If the vehicle has a failure, and it is coming straight down, the people in the vehicle will get hurt. I think even 75ft is optimistic, and more likely 200 feet or more will be needed to operate a parachute to save the occupants from injury. Parachute fail occasionally, that is why skydivers carry 2, and a spare chute won't save a crashing vehicle below 200ft.

In horizontal flight, if a propeller is damaged or an engine is down on power, the vehicle will need to land soon. Is there a safe place to put down over an urban area? The planning needs to be done before the flight, or for sure before the event occurs. Weather changes sometimes quickly, can the vehicle handle the unforcast weather properly? The hybrid winged vehicles are better in some respects. They can usually glide in an engine failure situation, but is there a suitable place to land near where this happens?


We need to let the smart people look at this carefully, so that we don't hurt folks.

1500 hours or Nothing

 We seem to be at a weird crossroad. Congress is trying to mandate that the first officers, if they are in the cockpit must have 1500 hours for safety reasons. They are also being pushed to keep both pilots out of the cockpit, and leave them on the ground.

The UAV or drone folks want to keep the people out of the cockpit, while the safety people want more hours for the folks in the cockpit. I kind of get it, I guess, pilots are highly paid people, and technology is getting better, such that UAVs are pretty reliable. If only drones are in the air, then they should all cooperate, and everyone should be happy.

Well, how would you feel about a cockpit with no one in it while you were being whisked on your vacation in the Bahamas? There is someone on the ground paying attention to your airplane, should anything be out of the ordinary. They are paying attention to six or seven other flights as well, heck aircraft on autopilot re all pretty reliable.If the autopilot notices anything unusual, the pilot on the ground will control the aircraft to a landing.

Ice seems to be a common failure mode for recent passenger aircraft crashes. The Colgan 3407 had a captain that had switched aircraft types, and may have been confused about proper action with ice. The Air France 447 crash had ice that caused the autopilots to give up, and ask the less experienced co-pilots to fly the airplane. It is probably good that the FAA mandate more experience to crews, to insure that should something out of the ordinary happen, they will be able to take the proper action.

How much experience should someone on the ground have, if they are needed? Based on recent incidents, they ought to have lots of experience. They will not be dealing with "normal" flights, only abnormal situations. Maybe they will trying to get an ice laden commuter to a safe place at an airport, or a larger transport aircraft through a massive thunderstorm with no reliable airspeed indication. Either way, they will need all the feedback they can get to know what the situation is.

Airplanes are built on many systems. The pilots job is to be able to manage all these system in all situations. Sometimes the indications are providing questionable feedback, and correlating different dis-separate systems can yield hints to the true trouble. The human brain is still better at tasks where the data is really fuzzy.

There are arguments, should pilots be trained in full motion simulators, or are fixed simulators good enough. Well there certainly is a good bit of seat of the pants information that is available in a full motion simulator, but for many situations, the basic procedure trainer will get the normal flying situations covered.

 Should the remote pilot be in a full motion cockpit to help fly this broken airplane? I don't think anyone is considering that. Mostly the remote pilots are going to be expected to fly from a desk in an office somewhere.  Typically it will be a cockpit looking desk, but the chair will probably be on wheels, and just a couple computer displays will be in front of the pilot.

Depending on how bad the broken airplane is broken, it may not be able to provide any feedback. Maybe sensors have gone bad, and that is why the autopilot has given up would be the primary reason the remote motion cockpit will not work. Sometimes the computers in the aircraft don't work, and the remote pilot is going to rely on backups to backups.

Datalinks go bad. We are all used to always on internet, but how often does your internet go out? Your home internet isn't moving, so it should be very reliable. If you have satellite TV when it rains, what happens? Well, imagine flinging through the sky at 40000 feet, in a thunderstorm, 1500 miles from any land, how reliable will the communications link be there? Satellite is pretty reliable, especially in the rain? How about ground links, 1500 miles from the nearest based station, VHF and above won't cut it, and HF is too slow. So the autopilot should be 100% reliable, after getting struck by lightning 2 or 3 times? maybe.

Look I love technology, but I like to relax on my vacations. I don't mind paying a few bucks for the pilot to be sitting up in the front of the airplane. He has some skin in the game. If he messes up, he gets as hurt as me. A guy sitting in an office, might not think things are so important.

What do you think?

Drones In Airspace

There seems to be a huge "land grab" trying to happen these days. Drone builders are wanting their products to be sold at all cost. I don't blame them, who doesn't want their product to sell. There are a couple issues to work out before we have our sky's filled with buzzing aircraft.

1. Safety
The airspace already has many aircraft in it. People fly their personal airplanes everyday, and there are airliners flying others even more. How are we going to insure these different aircraft don't come in contact with each other. To keep the "little guys" out of the way of the "big guys", there are specific rules. There is positive controlled airspace (the airspace between 18,000ft and 60,000ft) where anyone flying there is required to have altitude reporting transponders, and IFR flight plans and ATC is responsible for separating aircraft.

Below 18,000ft, the rules are different. Pilots are to see and avoid each other as the first line of defense. Aircraft flying easterly are to use odd thousand altitudes (IE 7000ft, 9500ft, etc), and flying westerly even thousand feet (IE 6500ft, 10,000ft). That helps separate aircraft, and mostly avoids head on collisions. The pilots are responsible for their own separation, when flying on visual flight rules (VFR). Pilots flying on  instrument flight rules (IFR) with a flight plan have ATC keeping an eye on them, as long as they are above the altitude that the RADAR can see them.

Piloted aircraft have great visibility, usually. The windows allow a wide field of view, and the pilots can rely on peripheral vision to see what is happening around them. Pilots are taught to scan the sky, and can usually pick out another aircraft well before most of the passengers even know it is there. If there is more than one pilot, the second pilot is also scanning, and the two pilots will be able to keep each other aware of any hazards.

While it sounds pretty fool proof, there are still mid-air collisions. Transitioning altitude accidents are the most common. Climbing from the departing airport to 10,000ft an aircraft will transition several even and odd thousand altitudes. If one of the pilots in that altitude, or the climbing aircraft isn't scanning, they may miss the climbing aircraft. Similar with descending from cruise altitude to the arriving airport, there may be conflicts. There are differing speeds of aircraft as well, and this can cause issues. If a 200mph aircraft is converging on a 120mph aircraft, at a 90 degree angle, even if both aircraft are going westerly, for instance, they may be in conflict, and have to avoid each other.

Drones whether remotely piloted or autonomous may pose a greater risk. They may fly following all the same rules as piloted aircraft (even/odd altitudes,see and avoid, flight plans, and ATC separation) they don't have the same capabilities. There are limitations of cameras if so equipped, communication latency, and other sensors are lacking.

The field of vision for most cameras isn't anywhere near the 180 degrees most people have of peripheral vision, and that is the biggest trouble. What the pilot can't see, they cannot avoid.  Radio waves can only go at the speed of light, maximum (roughly 1 foot per nano-second, 5280 feet in a mile = 5280 nano-seconds or about 5 micro seconds, then a thousand miles would be 5 milliseconds). What the pilot sees will have to be send via some radio from the aircraft to the pilot.

Being thousands of miles away from the actual aircraft that the pilot is flying will cause latency to the controls, that is basic physics.  It doesn't sound like much, but it matters, since what the pilot sees is from say 5 milliseconds ago, and what the pilot does takes another 5 milliseconds to start the affect. If the aircraft is satellite linked, start making that seconds, since satellites are thousands of miles up and the radio signal is not going straight up and straight down.

Communication links fail. They just do, it may be something completely random, like a backhoe taking out a ground based link. An antenna may break or fail due to ice or other cause, and sometimes radios just quit. Who controls the drone then? Maybe the drone should stop or fly in a circle until control comes back, it isn't on a flight plan at that point so what should ATC do about it? What happens when it runs out of gas, or battery? Can a drone call mayday?

There is lots of talk about aircraft broadcasting satellite based location information. The technology is there to do it, and many aircraft will in the future do that, but not all aircraft will ever. It is still legal to fly an aircraft without an electrical system. The systems to broadcast satellite based location are still thousands of dollars ($5000-10000), and this can sometimes represent more than half the cost of a whole aircraft (yes, you can buy an airplane for under $20,000), not everyone flies a multimillion dollar jet. How will the drones ever see one of these non-GPS equipped aircraft? (how about if the drone manufacturers develop a small, battery powered  $500 ADS-B in/out system that they can give to the general aviation community?)

In the current situation, a collision scenario is not an if but a when. Will it be a 747 with 300 people and a drone, or will it be a commuter jet with 50 people? Does it matter? Who will get the blame, the people who pushed the bad legislation through, or the poor pilot of the drone (could you live with yourself?)


2. Privacy
What are people wanting to do with all these drones. The manufacturers have all kind of ideas, like launching weapons, and surveillance. I don't think we need some municipality having armed drones, and the local sheriff deciding they need to get the drone out to control the crowds. 

Who will be buying and operating these drones. The manufacturers want nearly everyone to have one. More users mean more money. So maybe the local newspaper will use them to help get to a newsworthy site quickly, that seems good. What about the gossip paper, who might be nosey, or someone fishing for something to report, should they be able to go look for stuff to report?

You say, you don't have anything to hide, so it shouldn't bother you. I normally don't have anything to hide, but I don't really want free reign on people just looking! Not that anyone would want to see me naked, but do I need to close all the shades every time I am changing clothes in my bathroom with only a window well above me? Say I do something that may look shady to someone who flies over at the wrong time, might they report that?

Imagine the drones are connected with surveillance devices besides video cameras? Listening devices and radio scanning devices come to mind. Maybe someone wants to listing to what is happening below. Never mind bugging cell phones, that is too complicated. Detect things from the source. Think it can't happen?

3. Noise
The folks who don't like airports in their back yard should be all up in arms about dozens of these drones taking off and landing in their neighborhood. Many of the bigger drones will need real airports, and make real airplane noises. Smaller drones may may buzzing noises, that may not be as loud as real airplanes, but could still be annoying.

Remember the plan is to have more drones than current piloted aircraft. Lots of quiet things make a noise, anyway. What will people do about that problem. More make more noise, it all adds up.


Thoughts about solutions.

I am not totally against drones. They will have their purpose. Mostly in combat situations, not spying on the general citizens. The test areas should be out over completely unpopulated areas, like the ocean, or wide open desert areas where people don't typically fly.

If the drone builders can come up with a workable solution for the see and avoid problem, that doesn't cost the people in the civilian airspace then I could see limited mixing. It doesn't seem reasonable to make people who have nothing to do with this technology pay to make them work. (the old change the laws until your business plan works model, shouldn't apply in this situation)

Armed drones should never be allowed over civilian population, in the US or any other country. Armed drones should only be allowed in front line combat. This bit of common sense will be ignored, and people will get hurt, but it will be justified to most people.

Aviation is expensive. There are limited exceptions, but to play with the big boys, it will take real money.