The Abstract Truth

Archive for the ‘flying’ Category

Flying Car For Sale on eBay

Posted by rbpasker on January 12, 2008

Another flying car-type vehicle that came and went. From reading the comments and Q&A (not to mention the number of hits I get on my blog), there is a tremendous amount of interest in these vehicles!

The last Concept Sky Commuter aircraft in Existence

Posted in flying | 1 Comment »

Another (More Promising) Flying Car

Posted by rbpasker on October 11, 2007

Read about the TerraFugia and visit their site.

This is an FAA-certificated Light Sport Aircraft (LSA), which means it probably has a chance!

Posted in flying | 2 Comments »

For Want of a Nail

Posted by rbpasker on August 15, 2007

One of my favorite books in the world is David Hackett Fischer’s Historians’ Fallacies : Toward a Logic of Historical Thought because it brings the rigor of logic to the study of history. Today I get to take Fischer for a tour of the computer room and show him the errors of his ways.

Under the heading Reductive Fallacies, Fischer writes:


In the computer room, however, broken nails are responsible for lost battles all the time.

In 1985, I was working at the Bank of New York on their government securities clearance system, which failed when a signed 16-bit index overflowed from +32,767 to -37,768, and started overwriting memory. BoNY had to take out a $32 billion overnight loan from the Federal Reserve, and pledge the bank itself as collateral. (Although I was not involved in the application which had the bug, I spent the night in the computer room with the folks who were because I had responsibility for the underlying TP monitor software.)

A few days ago, Los Angeles International Airport was shut down because of the failure of a failed U.S. Customers computer system. Was it a terrorist? A hacker? Nope, it was a failed LAN card. It took 9 hours to fix, and stranded 17,000 travelers.

On the battlefield, there is a tremendous amount of redundancy: troops, ammo, tanks, etc. One guy falls, and there are 5 more to take his place, and the reductive argument doesn’t work.

In the computer room, however, there are lots of nails, the failure of any of which is sufficient to cause catastrophic failure.

As computer professionals, we have a responsibility to build redundancy into our systems.

Posted in flying, work | 1 Comment »

New Challenges for the Flying Car

Posted by rbpasker on August 13, 2007

We’ve seen a resurgence in interest over the past few years of the “flying car,” one which can operate seamlessly in both land and air traffic environments. The idea is that highways would become obsolete for most trips of up to a few hundreds miles, reducing congestion and being able to fly over geological obstacles such as mountains, rivers, and lakes. Some day we will all have these flying cars and go point-to-point by air, as easily as driving down the freeway.

Flying cars can be broken down into two broad categories: car-o-planes (“cars that can be flown” or “planes that can be driven”) and the VTOL (“vertical take-off and landing”) . A car-o-plane is a car you can drive to the airport, take off on a runway, land at another airport, and drive away down the street. There have been a few of these vehicles made, such as the Taylor AeroCar. One brilliant individual even designed a flying car based on the Ford Pinto. I guess the hazard of having the gas tank behind the axle wasn’t dangerous enough. The VTOL flying car takes off and lands vertically, like a helicopter, and doesn’t need a runway, just a parking lot or a field. The Moeller Skycar is the current favorite in this category.

The Taylor AeroCar

The Mitzcar Flying Pinto

The Moeller SkyCar

Much of the work on flying cars has been on mechanics and aerodynamics: how do you make something that fits in both environments, and how does it fly?

Certainly the mechanics and practicalities of a flying car are important, but there are three three big non-mechanical challenges that must be overcome before we can see one of these in every garage: weather, obstacles and terrain, and in-flight emergencies.

Have you ever taken a car trip where the day starts off reasonably nice, and somewhere down the road, the weather starts to look threatening. First the sky starts to get cloudy. Nothing mean, like a big thunderhead, just some overcast or maybe some fair-weather puffy “Simpson’s clouds.” Fifteen minutes later, the wind picks up, not too strong, maybe 15 miles per hour, and a little gusty. Then there’s the smell of rain. Have you ever smelled an approaching rain storm? It happens a lot in the summer, when the air is moist. Here come a few drops. The wipers go on intermittent, to match the speed of the drops, and soon you realize they have to go on full time, first slow, then fast. Before you know it, you’re in the middle of a rainstorm. At this point, you have a few options: pull over, turn around, or keep driving. How many times have you actually pulled over or (less likely) turned around because the storm was too strong? How many times have you driven on, thinking to yourself, “I should have pulled over when it started, but I’m almost through it now”? Such a storm, which thousands of drivers survive every day somewhere in the world, would be disastrous in a flying car, but certainly no more
disastrous than for a week-end pilot in his Cessna. Forecasts and live weather information in the cockpit help, but they don’t prevent people from flying into bad weather. Even experienced pilots licensed to fly in bad weather are caught off guard and get killed. As the saying goes, “its better to be on the ground wishing you were in the air, rather than in the air, wishing you were on the ground.” Amen.

The second issue with which pilots have to contend is hitting something, either an obstacle like a tower or a bridge, or terrain, like a mountain. In the flying community, this is called “controlled flight into terrain” (CFIT). With cars, we know that if we stay on the road, we won’t hit a tree or a mountain. (What amazes me is how many 50 mph roads there are with no center divider, and how few head-on collisions there are.) With flying vehicles, we can fly anywhere, even right into something. The latest technology, which is now required equipment in almost all jets and turboprops, is called the Enhanced Ground Proximity Warning Systems (EGPWS). EGPWS, however, doesn’t prevent the pilot from flying into things, its just alerts him to the danger. Experienced pilots still fly into things.

Imagine yourself driving along and your car fails. Probably 99% of the time, you can just throw on the flashers and pull over (or coast) to the side of the road. Sure, the engine isn’t running, but you know what to do: turn the wheel and head for the side of the road. Now think about a failure at 5,000ft. What do you do? You either fix the problem and continue on your merry way or land. Most pilot training (initial and advanced) is spent learning to deal with in-flight emergencies because how one reacts in an emergency has a lot to do with getting on the ground safely. Some airplane manufacturers have installed the “get out of jail free card”: a ballistic parachute that can be activated in flight and will lower the plane to the ground even if a wing falls off. They claim on their website to have save 203 lives, but what they don’t say is that may lives have been lost in planes equipped with this system, even when the parachute was deployed. Even Cory Lidle’s plane had such a parachute.

Some people will see this post as pessimistic, thinking that I believe flying cars will never happen. What this post really about is identifying the challenges that a flying car would face if it ever became possible to put one in every garage. I am hoping to spur debate and research on solving these problems so that when the flying car becomes a reality, it will be for a much wider audience than just the trained pilot.

Posted in flying | 1 Comment »

Smoke City

Posted by rbpasker on August 9, 2007

In Fog gets in your eyes, Roger Shuy writes:

Fog, 83 degrees, winds west at 13 mph, humidity 16%.

Fog? When I looked outside, for the life of me I couldn’t see any fog. That black stuff in the air is smoke from the huge forest fires about 30 miles from here, dangerously close to Language Logger Sally Thomason’s summer cabin home… The reporter’s choice of “fog” to report “smoke” made me wonder about the inventor of weather reporting terms.

The reporting terms for weather are highly stylized and transmitted in a cryptic meteorological report called a METAR
These are METAR visibility definitions
b. Fog. A visible aggregate of minute water particles (droplets) which are based at the Earth’s surface and reduces horizontal visibility to less than 5/8 statute mile and, unlike drizzle, it does not fall to the ground.

c. Smoke. A suspension in the air of small particles produced by combustion. A transition to haze may occur when smoke particles have traveled great distances (25 to 100 miles or more) and when the larger particles have settled out and the remaining particles have become widely scattered through the atmosphere.

If the weather observation was made by an unmanned station, then the station may not have had the ability to differentiate between smoke and fog. Or the observation was made by a person, who was trying to communicate to the reader that the visibility was “less than 5/8 of a mile,” a condition is particularly important to pilots. Smoke , on the other hand, doesn’t specifically imply any loss of visibility. 

In either, case, the repertoire of terms available to the meteorologist is quite broad, but they are also meteorology terms of art, and not English.

Posted in flying | Leave a Comment »

Flying at High Density Altitude

Posted by rbpasker on August 9, 2006

[Before reading this article, it might help to review the definitions of indicated , ground, and true airspeed]

High density altitude (DA) affects both aerodynamic and engine performance.

In terms of aerodynamics, the difference you will see at high density altitude (DA) is your true airspeed (and, with no wind, ground speed) will be higher than at sea level, for the same indicated airspeed. For example, you when you rotate at 67knots indicated, at sea level, you will be at 67 knots TAS. At 8,000ft DA, however, 67KIAS is 76KTAS. With no wind, you’ll be rotating 9 knots faster ground speed. Try this TAS calculator.

Some things to watch out for:

  • You will have a longer take-off and landing roll than at sea level. Expect that the ground will be moving past you much quicker on take off and landing.
  • Your turning radius will be higher than at sea level (for the same indicated airspeed and bank angle) because your ground speed is higher. This means you will need to start your turns in the pattern EARLIER, since you don’t want to slow down or increase your bank angle in the pattern.

From an aerodynamic perspective, your plane is certificated upto its gross weight. there should not be any difference when landing at 0’DA versus 8000’DA.

From a POWER perspective, your non-turbocharged airplane will not produce as much power at 8000ft DA as it does at sea level. It is especially important not to be behind the power curve at high DA is because POWER equals ALTITUDE. Remember your slow flight? Pitch controls airspeed, power controls altitude. If you get behind the power curve, you may not have any reserve power to climb or arrest your descent, even if you firewall the throttle.

Carburetors and most fuel-injection systems mix air and fuel by VOLUME, not weight. But your engine cares about the weight of air, not the volume, because weight is a measure of the number of air molecules. At high DA, therefore, there are many fewer air molecules in the same volume of air, so using the same air-fuel mixture at high DA means that your engine will be running much richer. You need to learn how to lean your engine to produce best power. Best power is the term used to describe the air-fuel mixture ratio at which the engine produces the best amount of power.

In a nutshell:

  1. expect longer landing and take-off rolls
  2. make your pattern turns earlier, so you don’t have to increase bank angle
  3. stay ahead of the power curve
  4. lean to lean for best power

Posted in flying | Leave a Comment »

Do you have a jet rating?

Posted by rbpasker on December 17, 2004

When I tell people that I’m a pilot, I’m often asked a questions like: “Can you fly big airplanes?” “Do you have a jet license?” or “Now that you’re a commercial pilot, can you fly 747s for United?”This is my opportunity to explain some of the mysteries of a pilot’s license.

The FAA recognizes three different kinds of credentials for pilots licenses: certificates, ratings and authorizations.


Certificates are the level of license the pilot holds. The four most common certificates are: Student Pilot, Private Pilot, Commercial Pilot, and Airline Transport Pilot (ATP). [1]

Student pilots may not take any passengers and must obtain permission from his instructor even to fly solo.

Private Pilots may take passengers, but cannot be paid for the flight.

Commercial Pilots may be paid for pilot services, like transporting passengers and cargo, towing banners and gliders, or spraying crops.

And an ATP may fly for the airlines.

A Student certificate is easy to get: you just fill out a form and get a flight physical. To get a private, commercial or ATP certificate, you have to take a check ride, the “final exam” for the certificate.

The check ride consists of two parts. The oral part of the test is a Q&A on your piloting knowledge, and the practical test is where you actually fly the aircraft (or a simulator) with an FAA-authorized examiner on board. The maneuvers the candidate has to perform, and the criteria for evaluating the maneuvers are are specified by FAA regulations. For example, for the Private Certificate, you have to demonstrate that you can land an airplane within 200 feet of a chosen spot on the runway. For the Commercial Airplane, you have to land within 100 feet of the spot.

But before you can take the checkride, though, you have to jump through a lot of hoops.[2] First, you have to obtain a certain amount of flying experience. For example, you need 40 hours of flight time for the Private certificate, and 250 hours the commercial certificate. Second, you have to pass a written test with at least 70% of the multiple-choice questions correct. Third, you have to receive ground and flight training from an FAA-authorized instructor. Fourth, you have to get your instructor to “sign you off” with an “endorsement,” meaning he signs your pilot’s logbook with a note that says you have received the required training, and you are prepared to take the checkride.


Just because you have, say, a commercial certificate, it doesn’t mean doesn’t mean you can fly any old kind of aircraft. On every certificate there is a list of Ratings, which specify the kinds of aircraft you are allowed to fly. Ratings are broken up into 5 categories: Airplane, Glider, Rotorcraft, Lighter-than-air (LTA), and Powered Lift.[3]

Certain categories have classes, which further subdivide the kinds of aircraft :

  • Airplane — Single-engine Land (ASEL), Multi-engine Land (AMEL), Single-engine Sea (ASES), Multi-engine Sea (AMES)
  • Rotorcraft includes Helicopters and Gyroplanes. A Gyroplane has both a rotor for generating lift, just like a helicopter, and a propeller, like an airplane, for moving forward.
  • LTA includes Airships (blimps) and Balloons (both gas and hot air)

When someone says he “working on his pilot’s license,” he usually means he has a Student Pilot Certificate, and is working to get a private certificate with an ASEL rating.

Once someone has at least a private pilot certificate, he can add to that certificate as many other ratings as he likes, simply by training, getting signed off, and taking another checkride in the category and class desired. Getting a rating within the same category (e.g., someone who holds ASEL wanting to add AMEL) is easiest, because you just have to learn the differences between the single-engine airplane and (typically) a twin-engine airplane. Getting a rating in a different category (e.g., holding ASEL and adding Rotorcraft-Helicopter) requires a lot of flight time because it requires the pilot to log the same amount of flight experience in copters as a student pilot. For example, when I added on a single-engine seaplane rating to my private certificate with a land plane rating, it only took 5 flights and 7 hours of flying. To add on a Copter rating, it took 50 of flying hours because I had to have the same number of hours as any other novice copter pilot. When getting such an “add-on” rating, the examiner may omit many portions of the exam that were already covered in a previous checkride, like weather knowledge, flight planning, and navigation.

So, now that you have that coveted multi-engine rating in airplanes, does it mean you can fly a 747? Unfortunately not. The ratings described above are only good for aircraft up to 12,500 pounds maximum weight. To fly an aircraft that weighs greater than 12,500 pounds, you must be rated for that exact type of aircraft, so all 747 pilots must have a 747 Type Rating.

People also ask about a “jet rating.” There isn’t any such thing as a generic jet rating, but the regulations do say that to fly a turbojet aircraft, the pilot must have a type rating for that particular jet. So even though the Cessna Citation weighs less thatn 12,500#, the pilot-in-command must hold a Citation Type Rating.

There are some special pilots out there who have so much experience in flying that the FAA will issue them an All Types rating for a particular category and class. If you ever meet one of these people, be duly impressed, as they are the true masters of the sky.

Ratings may also have limitations. For example, student pilots must have a certain amount of night flying experience before taking the checkride. But that would be impossible in Alaska, where the sun never sets in the summer. So the FAA makes an exception for Alaskan pilots, and issues them a license that says “Day VFR Only” until they successfully complete the night flight training requirement either in the lower-48 or the next winter.


An Authorization is an entry in your logbook (also called an endorsement) signed by a flight instructor stating that you are authorized to perform certain special operations:

  • High Performance — required to fly airplanes with more than 200 horsepower per engine
  • Complex — required to fly airplanes with retractable landing gear, flaps, and a controllable propellor
  • Tailwheel — required for airplanes that have a wheel on the tail instead of under the nose
  • Glider Tow — required to tow gliders into the air
  • High-altitude — required to operate pressurized aircraft at 25,000ft and above.
  • Category II and III — required to fly an airplane that can land itself in the worst weather

  • So, next time you meet a pilot, ask him “What type of certificate do you have?” and “What ratings do you hold?”

    [1] In addition to the Commercial or ATP certificate, Instructors also hold a certificate called a Flight Instructor Certificate. This identifies the kinds of instruction the pilot may give.
    [2] The requirements here are when you’re getting the certificate in Airplanes. They could be different for other aircraft.
    [3] There is also a rating called an Instrument Rating, which permits the holder to fly solely by reference to instruments, which is how you can fly in clouds.

    Posted in flying | 2 Comments »

    %d bloggers like this: