Taxiway Lighting Systems

Taxiways - Lost and Found

First, a taxiway is a communication path on an airport connecting runways with ramps, hangers, terminals and repair facilities. Larger airports the taxiways are hard surfaced to support heavy aircraft.

The Blue Lights mark Taxiway Edge lights and emit blue light. They make finding your way around easier. Jeppeson Charts have taxiways well marked for the pilots benefit.

Jet Ports have high-speed exits off the Main Runways to facilitate moving large planes. Once off they use the taxiways.

The center of the taxiways have a single yellow line to help you center your plane for taxiing.

The taxiway edge markings have two different purposes. If they have two solid yellow strips it marks an edge of the taxiway that separates the taxiway from a surface that doesn't, for instance, support a plane straying into that area.

The second is two broken double yellow strips that separate a surface that does support a plane crossing over onto it's surface but is not the actual taxiway.

Taxiways have Yellow Information Blocks as they approach a runway. The blocks contain black lettering and numbers that provide taxiway information when erected signs are not possible.

The lighting and informational choices expand as the complexity of the airport increases. Night increases the possibility of confusion. 

If  you fly into busy airports the following link is complete and will help you in the identification possibilities before you actually take off and, of course, is a part of your pre-planning. Airport Lighting Systems.

Garmin Pilot for I-Phone and I Pad - Possible Problems

Garmin Pilot

As a backup, in private aircraft flying, the I-Phone screen is quite small. In turbulent conditions, during IFR approaches, controlling and reading the device is nearly impossible.

As a flight planning device it has exceptional features. Use a  Search Engine to find test results and/or detailed information on the Standard or Pro versions of the Garmin App and the many features the Garmin device offers.

The I-Pad has a larger screen. Easy to read screens, in flight, are a blessing. Information is available and good.

There are still some disadvantages that interfere with the I-Pad.

A common one is glare. Ever try and read a modern gas pump screen if sunlight is hitting the screen? You get the point. Glare on the I-Pad screen makes use almost impossible. Later models of the I-Pad have brighter screens that make use possible. Changing the position of the I-Pad screen helps. Ton of kneeboards and mounts that alleviate some of the glare drawbacks.

Electrical discharge in the latest and greatest I-Pads, controlled by fast processors, adds up to heat. Heat will cause an I-Pad to shut down when you need it the most. Aircraft cockpits in direct sunlight and dark surfaces allow heat to build quickly inside the plane. Couple this with any heat producing electrical device and shutdown can occur. 

When an application uses more power than what is supplied from a charger, the time of operation is compromised. The power required to operate all the bells and whistles is greater in the latest models. Cutting the power to some features will eliminate the discrepancy between power out (device) and power in (charger).

The trade off between size of the I-Pad and placement in the plane may present problems. If the device covers instruments that is a no-no. Yoke mounting can eliminate the instrument problem. A neat idea is mounting the device on the co-pilot yoke. Aiming the device at you makes reading the information provided easy. Placing the I-Pad on the floor and bringing it up to view charts is another solution. Be careful, if unsecured by a retaining structure, the I-Pad slips behind the seats. Moving your head about to find the I-Pad can result in disorientation.

Finally, trying to use any device in turbulence is very difficult when your holding the I-Pad with one hand and inputing information with the other hand. A dash or yoke mounted I-Pad is safer to operate.

Modern gadgetry is great but a few problems exist. Keep in mind, though, the many great features that exist to make the purchase of the App a wonderful addition to flight safety.

Pussy Footing Around - Detecting a Cushion

Sensing Float (Buoyancy)

In landing an airplane sensations you receive from the plane to you are very important. Short fields require sensitivity to the subtle clues that affect lift. Floating is not nice as you run out of runway.

You want a slight cushion, when you land, to flare out, check the descent of your plane and contact the ground. This is the very slight touch of your wheels in a perfect landing. The "Ahh, what a landing" reaction from pilot and passengers. 

This is "flying the edge" to some folks. To arrive at the edge and not drop off the cliff is the goal in every landing.

We talked about lift reserve before. The perfect landing results from a cushion of reserve lift that allows the plane to touchdown quickly with as little float when you pull back on the stick or wheel and stall.

When you pull back on the stick you don't want to feel a surge of lift that requires a checking of the descent from you!

At altitude you can test the effect by flying a slow glide at the very edge of a stall. When you pull the stick back a few inches the flight path of the plane does not go up. Instead the plane begins to stall and settle. The flight path goes down. In a fast glide, with lots of reserve lift, when you pull back on the stick a few inches, the plane balloons with a firm push into your bottom. Net result is an upward flight path and a much longer movement forward before the plane settles down to land.

At altitude you can't  really see the deflection of the aircraft upward. You feel it. In an actual landing flare, near the ground, the slightest ballooning or settling of the plane is very apparent to the eye. You feel the changes you make in the stick position by sensing the slight weight changes (lightness or heaviness) that occur from stick handling.

If a pull back on the stick makes you feel slightly heavier you are gliding too fast and the plane "floats" until the glide slows.

If you pull back on the stick and you feel lighter, like going down in a fast elevator, your reserve of lift is limited and you descend.

Your perception of weight change is very sensitive. You make a conscious effort to pay attention to that "sense" and act accordingly. If you are a passenger in the right seat of a small plane during the final stages of a landing you will see the pilot make small changes in the stick position (both back and forward) as he "senses" the planes descent to a perfect landing.

This gives credence to the term "flying by the seat of your pants" when landing an airplane.

In conclusion, sensing the cushion effect is important to a good approach and landing. Your senses become very sensitive as you glide lower to the ground and control movements are limited to prevent major changes in flight attitude (up and down).

The Breakdown of a Spiral Turn Before the Breakup

The Breakdown:

Something disturbs the plane in straight and level flight at cruising speed. The right wing drops slightly. The plane enters a gentle sideslip to the right. In a slip a crossflow of air initiates a dihedral response to pick up the right wing.

The vertical tail fin responds, simultaneously, by yawing the plane slightly to the right. If the plane is spirally unstable the rudder (tail fin) forces the plane around before the dihedral had time to pick the right wing up.

The rudder produces a yaw which introduces an over-banking tendency while the plane turns. In a turn to the right the left wing is moving, at the moment, faster through the air and generates more lift. At the same time the right wing is slowed a bit and generates less lift. The net result is the left wing goes up slightly and the right wing drops. The over-banking tendency cancels out the attempt of the dihedral to the right wing to return the plane to level flight. Net result the right wing stays down.

The slight sideslip to the right continues and the dihedral tries again to right the right wing to stop the sideslip. The vertical tail again over-rides the dihedral and the plane enters a new over-banking effect. This process will repeat itself unless stopped.

If this isn't stopped the plane enters a steeper bank and a tighter turn. This continues if you don't interfere. 

The g-load increases due to the centrifugal force build-up. The increase in load forces the plane to drop its nose and pick up speed. The plane has a built-in tendency to keep itself at a constant Angle of Attack. The extra load, created by the centrifugal force build-up, creates a situation where the plane can only maintain a constant Angle of Attack by picking up additional speed. The dive combines with the spiral turn to create a spiral dive.

When an increase in the bank reaches a certain point another effect forces the nose of the plane downward toward the earth. In this deep bank the earth is on the right side and the sky is on the left side. The rudder (vertical fin) continues to push the plane around to the right. It now is pushing the plane into a dive toward the earth.

In summary, this is what a plane "wants to do" once it is in a turn. The plane wants to do this even when the pilot is on the controls. 

This, in previous posts, is the anatomy of the "death spiral" that causes many lost lives where instrument flight skills are lacking and/or the pilot tries to fly an airplane so it makes him "feel good or more 'natural'."

Flight Controllers have testified about their inability to talk an untrained pilot out of a "death spiral." They try to put the aircraft into a flight attitude where their sensations are "more natural." In effect, they don't believe what the plane's instruments are telling the pilot about the actual attitude of the plane (a deep spiral dive).

This is a safety lesson on proper instrument pilot training. Knowing the normal tendency of a plane, in a turn, can set you up for a vestibular illusion that may end your and your passengers lives in a needless spiral dive accident.

No Controls Touched - Will a Plane Fly Straight?

Will a plane fly straight or turn away from it's cruising straight ahead attitude of flight , if you release the controls?

What does an airplane really want to do concerning the direction of its flight? 

Unfortunately, aircraft built to American specifications don't have the stability to remain straight and level with the controls released.

A pilot knows this if he experiments at a safe altitude. Release the controls and the plane will enter a turn. Pilots say the reason a plane enters a turn is because of:

• Torque
• Stiff controls
• Wing heaviness

Planes will enter a turn. Once into the turn they will keep increasing the angle of bank, the rate of turn, the speed and the rate of descent. This results in a true spiral which is an ever tightening turn combined with an ever steepening dive.

The end result, if the plane is left to its own fate, is the plane will break up in this tight corkscrew because of excessive g forces that exceed the aircrafts maximum load limits.

The spiral looks like a spin except the plane's controls will function in a normal manner and no stall is involved. You can recover from a spiral dive any time you elect to use the controls.

The entrance into a spiral begins when something disturbs the plane's right-left sense. The aircraft will respond to the disturbance in two different ways simultaneously. One is a planes vertical tail will yaw the plane around to point itself into the direction it was actually moving. At the same time its tendency to refuse to sideslip, due to the dihedral angle of its wings, will cause the plane to lift one wing and drop the other to regain its lateral balance. Both events occur together. 

The turn causes the relative wind, to blow slightly crosswise at the plane to affect both the vertical tail and the wings dihedral at the same time. A plane will respond to a disturbance depending on weather the yaw effect or the wing-righting response is quicker and more forceful.

Think about a plane that has a very small tail and a pronounced dihedral. If a gust throws the ship into a slight sideslip the right wing will pick itself up before the small tail has a chance to yaw the plane around to the right. After the disturbance the plane will resume its flight in the origiinal direction.

Now think of a plane with no dihedral and a large vertical tail fin. The gust above will cause the plane to turn entirely from the yawing. If it does recover, it will head in a different direction. 

Students think the vertical tail fin is there to keep the plane flying straight. Instead, it actually makes the plane turn.

All of the above also depends on tail length and wing span. The density of the air plays a role in the dampening effect. A gust may cause a quick response but the air density will damp the quickness. A short tail and short wings will react quickly. Slower for a long tail-long wingspan aircraft.

Designing a stable non-spiraling plane is not worth the time for aircraft designers. They design a plane to actually help a pilot in controlling the aircraft. They contend that a spirally stable airplane is hard to fly in rough air. It will tire the pilot out over a long period of time.

To a pilot, in a steep spiral turn, is that tendencies that exist in a plane with controls released will be noticeable when the pilot flies the turn.

Plane design should make stability a priority.