Aircraft Meteorological Data Reports

For the eyes of aviators only, others enter here at your own risk :-) ....AMDAR (Aircraft Meteorological Data Reports) is really neat. Some airlines participate in putting a small data gathering device on their aircraft. As the aircraft ascends/descends, a broadcast wind direction, gusts, temperature and more (http://amdar.noaa.gov/FAQ.html gives detail) is sent to a data gathering agency. One of the more important factors transmitted is moisture content. Currently, around 140,000 samples are collected/day. This means wx folks and aviators have access to almost real time radiosonde-like sounding data. One example using this data can be found at http://rucsoundings.noaa.gov/. "RUC" stands for rapid update cycle. If you are not familiar with the display format, take the Texas A & M tutorial (link on bottom of rucsoundings page). The format is a log-p skew-t graph, something that weather experts have been using for years. However, the Java version of this graph allows you to get dew points, temperatures, wind velocity and direction, etc. in the atmosphere over the airport you selected and up to about FL400. You can also lift a hypothetical air parcel to see if it is stable or results in bad things. It's easy to find freezing levels, saturation altitudes (where clouds are liable to form, etc.). Nice stuff for aviators. Even if you only use it in a basic way.

Audio in the Cockpit

I have aways had trouble with recognizing expired timers in the cockpit. Timed approaches, arghhhhh.

I have often wondered why we don't see more integration with timers and audio in the cockpit. Just think about that ILS and the audio (male or female) saying your timer has just expired.

Or how about "time to switch tanks honey" (voice is opposite sex, of course!). Just think about how many tank switches you have screwed up as a pilot (I cannot count). It's not easy to remember to look at the clock which is often located out of the main viewing area of the pilot. Even a yoke mounted kitchen timer doesn't work in a noisy cockpit unless it has a light and it is night time. There has to be a better way!

Modern FMSs have a timer feature, but even then, an expiration message shows up as a visual somewhere you are guaranteed to not be looking when it occurs.

Yes, there are some technical issues like how to handle a coinciding call from ATC, but I am sure that there are solutions. Audio stream mixing at this point would be good. Perhaps one timer's audio can be "critical" and used in situations like timed approaches. Critical time expiration messages would be mixed with ATC voice, perhaps a few "TIMER! TIMER!" shouts or something like that. All other expiration messages can perhaps be deferred until after ATC finishes their voice transmission. A tank switch would be in this category. In other words, non-critical times are deferred in the event of a collision with incoming ATC messages and a critical time expiration message is mixed with the ATC input.

It's about time we quit missing time expiration messages and audio seems like the best way to solve this problem.

Oshkosh 2009

I had a great time. This year I did a lot more socializing with fellow flight instructors whom I know from Palo Alto, CA. In addition, I renewed a lot of OSH-only acquaintances from last year at the house that I stayed at.

Lyle was at the house again and we can never seem to cover enough aviation topics fast enough and Karl, the king of curmungeon'ness was there too (it's a lie, he is really a teddy bear).

This was my 3rd year. The weather was great. Locals told me that it was one of the coolest summers in 50 years. It was cool because I was able to walk to the OSH terminal building (about 4 long blocks) in the morning without being drenched when I got there.

My favorite thing? (What was your favorite thing is everyone's favorite question). I don't know. It's all interesting and I always manage to learn something new. I think I enjoyed getting to know some of my fellow CFIs a lot better. Martin and I had a pen truce which helped and I always enjoy his humor even when the world seems to be melting around him. Terry is a walking encyclopedia on the history of aviation. I hope that some of it rubbed off on me. He also made me come to realize that I may like tail draggers after we both drooled over the large Sherpa with its tundra tires, great weight hauling capacity and it's extremely short field take off and landing specs.

Some say the airshow is Disney Land for aviators. I think it is wish land for aviators: I wish I had that airplane, I wish I had that airplane, etc.

It is special being surrounded by so many folks who have a passion for aviation. We all knew why we were there and we all had that gleam in our eyes.

Vwhy - Vwhynot

Summary: airspeed is a critical resource on go-arounds, touch and gos and IFR missed approaches.

When leaving the runway environment, airspeed is a critical resource. This is a no brainer when doing take offs from a full stop, but for some reason, many pilots unnecessarily let airspeed decay when conducting a go-around or touch and go by not adding take off power immediately. When deciding to climb in a draggy configuration (flaps down, gear down) it is important to immediately add power, then clean the airplane in order to minimize airspeed loss. In one extreme case, I was with a pilot doing a touch and go on a short runway who spend what seemed like an eternity looking for the flap switch, then he radioed tower to let them know he was going around. I am sure it was obvious to the tower a go-around was in progress. First fly, then talk! I teach my students that if you are not flying safely you have no reason to be talking unless perhaps it is a directive to avoid a collision. Do not be afraid to use the term "stand by" if your are in a heavy workload dealing with an "aviate" problem. Controllers will know that you are busy and will get back to them as soon as workload permits.

I teach the 5 C's which I learned from my instructor. Note the adherence to the all important priorities: aviate, navigate and communicate in that order:

1. Cram it. Don't stab the throttle - be nice to the engine, but don't wait either).
2. Climb it. When the flaps are down and the pitch is trimmed for landing, this means push on the yoke to prevent a trim stall. Eventually you will want to attain a balked or a short field airspeed, followed by Vy.
3. Clean it. Reduce flaps to manufacturer's balked landing setting or the setting used for short field take offs. Memorize your balked T/O or short field airspeed and keep this speed. Do whatever your AFM says about flap vs. gear up order - memorize this!
4. Cool it. This usually means open cowl flaps if the airplane has cowl flaps.
5. Communicate it. If this was an unplanned go-around, let tower know.

If you not aviating and navigating, you should not be talking. Never tell tower you are going around after being cleared to land until you have completed items 1-4.

Regarding IFR missed approaches, the 5 Cs apply with one twist. Upon reaching Vy, maintain it until you are absolutely positive you are clear of the highest obstructions within a conservative distance of the airport. (Study approach plates, VFR charts, MSA values, etc. for the lay of the land before your flight.) After this point, pitch the nose down and attain a cruise climb speed. At all times your climb rate must meet, preferably exceed, the minimum required climb rate for the missed approach being executed until reaching a specified level off altitude.

A mistake I see IFR pilots make frequently when executing a missed in the muck is a tendency to cram in full power, but not pitch up to attain Vy afer cleaning up and in a fast airplane this leads to a lot of scary horizontal, rather than climbing flight. Remember altitude is your friend. Once the decision is made to execute the missed, not only is it important to have memorized the first few items on the missed approach, but it is equally, if not more so to execute the 5 C's first with emphasis on attaining a Vy airspeed as soon as safely possible.

Propeller Bending

Wow, was I wrong (this is the first mistake I have ever made :-).

Propeller bending as shown in the picture below is an artifact that has something to do with the way digital cameras capture images and is not really due to the prop bending. At least not all the bending you see in the photo is real propeller bending.

Thanks Andrew for the education.

Some bending does occur, but not as much as my digital camera indicates, and this is what makes prop edge dings so dangerous. Think about steel wire. With a file make a small score perpendicular to the wire's axis. Start bending the wire. Where the break will occur? At the score. As a kid, I worked on farms, this is how I would cut fence or bailing wire that was too thick to cut with pliers. I used the cutter on a plier to score the surface, not cut it, and bend it back and forth until it broke. Think of a ding then as a stress point that over several bending sessions could lead to a propeller break. AOPA says that if a ding (also called a nick) is less than 1/32" wide or deep it can be deferred to next maintenance. However, I say that if an AP is nearby holding a file in his/her hands - why not ask? :-)

Lost Procedure vs. Diversion

Prop Bending Forward on Take Off (digital camera artifact)


Diversions and lost procedures often cause students grief on the private check ride because they are high work load items. High work load items are not an uncommon occurrence for the pilot. For example, the instrument approach is a high work load item. There is a lot of preparation and situational awareness activity on the pilot's part to make sure that the approach is successful.

Executing a lost procedure for real is also a high workload activity with added element of fear that comes from not knowing where you are located (how much fuel do I have? Do I fess up? Help!).

Once you are beyond an initial difference, lost procedures and diversions are one in the same activities. The initial difference is that with the diversion you know where you are located on your flight plan (we hope) and for the lost procedure you do not know your location. Once your location is known, processes for a successful outcome are identical: turn the airplane towards a desired position, estimate time and fuel required to get there. The lost procedure is covered in all basic aviation texts. You start by circling, climbing and determining your position. Circling keeps you over the same place. Find a ground reference and keep it in sight. A barn, a pond, etc. work fine. In short, if you don't know where you are at, don't go somewhere else - keep your present position. A circling strategy for most small GA aircraft is to reduce power (around 2200 RPM in most 160-180 horsepower engines)and attain an airspeed of around 90 KIAS. Add necesary power to keep 90 KIAS, but don't get carried away because you are trying to conserve fuel and you aren't going anywhere because you are lost. Bank about 15-20 degrees which tends to form a rather stable bank and do a gentle slow climb. You can do a faster climb with more power if you know that mountains will block VOR reception. You climb to see more things and get better radio reception. If you see something you know is on the chart, point the aircraft at that object until the magnetic compass is stationary and note the heading on the compass, then resume your position hold by restarting the bank you had a moment ago. If you use the reciprocal of the direction to the object you aimed at, you can draw a line of position (LOP) on your chart from that object. You are on this line. A VOR radial will do the same. Crossing two LOPs or using a radial and a range (DME value) will allow you create a position on your chart.

Ok, now we are past the initial difference. From this point on the diversion and the lost procedure are the same.

1. Determine where you wish to go from here - the desired position

2. On your chart, position a straight edge between current position and desired position

3. Obtain the magnetic direction to the desired position (see below)

4. Turn the aircraft towards the desired position and maintain the determined magnetic direction using your heading indicator (make sure your HI is correct!)

5. As soon as you turn from your known position, start a timer

6. While enroute to your desired position, determine the amount of time and fuel it will take to get there. Can you make it? No, then start circling and come up with a better plan

7. If an airport is your desired position, then start preparing - see below

Obtaining magnetic direction:
The best device I have seen for this purpose is a multifunction tool one my students devised to simplify the determination of direction, time and fuel. It is a transparent straight edge. Note that distance, time and fuel are linearly related to each other for a given airspeed (at a given power setting). My student used indelible ink to tick off 5 NM increments on the rule (sectional scale in her case). On a row immediately below each 5 mile tick, put amount of fuel consumed and on another row below that put time in minutes.

Ok, I realize that "speed" really means ground speed. If you use the ruler in a no-wind situation, it will tell you how far, how much fuel and how long with no math - one value below the other. If you know that you will encounter head winds (or tail winds) estimate the percentage difference. For example, I expect to fly over the ground about 10% slower than my true airspeed. This means you add about 10% to time and fuel. Of course, if you have an air data computer on board, use the wind/ground speed data to estimate the effects of wind. If you only have a GPS, start heading to the desired airport and once you have cruise airspeed look at the estimated time enroute value (ETE) and reassess remaining fuel - will you make it?

Borrowing from marine charts, magnetic direction is obtained by lining up your straight edge on your current position and your desired position (creating a desired track). Taking great care, move the straight edge towards a VOR magnetic rose keeping the edge parallel to the desired track (mariners use parallel bars). Obtain your magnetic heading off the VOR rose. With some practice it is amazing how accurate this can be as long as your ground track is reasonably short (perhaps less than 25-30 NM).

Preparing for an unplanned airport after departing from a known position
So far, so good. Now the workload really starts. Here are the essentials perhaps in the correct order:

1. Obtain the CTAF and automated weather frequency if available

2. Obtain the automated weather or contact the UNICOM or traffic at the airport to get traffic/pattern advisories.

3. Determine pattern altitude at the airport

4. Determine other pattern characteristics (left, right, obstructions, etc.)

5. When do I start my descent? Do I intend to overfly the airport at TPA+1000' to inspect windsocks and runway conditions or will I want to be at TPA 2-3 miles from the airport? Use the 4 NM/1000' rule of thumb for descent planning purposes. If you are at 5000' MSL and you need to descent to 1500' MSL subtract: 5000-1500 = 3.5 thousand feet. Multiply: 3.5 * 4 = 14 NM. This rule of thumb is based on a 120 kt ground speed and a descent of 500'/minute. If you plan to be at 1500' at the airport, then start the descent 14 NM from the airport. If you plan to be at 1500' 3 NM miles from the airport, then offset the descent slope by 3 miles and start at 17 : 14+3 = 17 NM.

6. After how many minutes from my departure point will I cross 10 NM from the airport? Announce my intentions on the CTAF to airport traffic at 10 NM, or have a handy 10 NM easy to identify ground feature in mind to clue you when to report. This can also be a VOR cross radial. If you are using GPS then look at the distance to destination value

7. Estimate how and where you will enter pattern before you arrive

8. Estimate a drop dead time - I missed the airport and it is behind me. Start another lost procedure process and find the airport from this new position. Another procedure is to use a "sentinel" which can be anything that "guards" the backside of your route. A VOR radial, a highway, a railroad, etc. Once you have crossed your sentinel, you know you missed the airport - stop, do not keep going.

The Main Message
The lost procedure and diversion are both high workload activities and can lead to significant stress, especially if you are lost because of the fear factor, and in both cases you have likely opened yourself to unknowns such as new airports, new terrain, will I have enough fuel, etc. Success depends on your ability as a pilot to keep a cool head and carefully follow the recipe (a procedure) for success. Using a diversion or lost procedure check list is a good idea. Success in all aviation high work load situations have the same demand: a cool, analytical head and clean execution of the proper procedure, one step at a time.

Be nice to your engine - some tips

Runway 17, Alpine County (M45)

Reciprocating engines use petroleum oil to lubricate surfaces. A running engine's critical surfaces are kept apart by a very thin film of oil. A piston pushes on a rod which pushes on a crankshaft bearing surface (called a journal). This is where reciprocating movement is changed into rotational movement. The downward force by the fuel burn on the top of the piston is tremendous. It's 0.5-2 thousands of an inch of oil that keep metal-to-metal contact from occurring at the bearing surface when these forces occur. Also, protection of this surface under high load conditions requires that the oil is warm (usually around 180 degrees F.). Putting a high load on a cold engine immediately after starting is destructive because oil that was on the surface when the engine last ran has drained off, it is hard for the pump to move viscous cold oil to the bearing surface and when the oil flow reaches the surface its lubricating properties are poor until it warms up. Learn to position the throttle so that when the engine starts RPM is around 1000 or less.

On cold days with cold engines, prime the engine early, right after checking fuel quality. An engine will not start unless vaporized fuel is available to the cylinders. An engine will not start well or at all on atomized or liquid fuel. Trying to start an engine without vaporized fuel and flooding are the common causes of pilots grinding on the starter motor to get the engine to start. Grinding a starter motor for extended periods can deep cycle the battery. On a cold day with a cold engine, an early prime allows time for fuel vaporization. By doing this you will usually find that your engine starts up easily with very little load on the battery. Be sure to skip the priming item in your check list if you do an early prime. If you would rather to do it according to an approved check list, then prime, but wait a minute or so (with the master switch off!) before activating the starter motor. Large, high horsepower engines start noticeably easier when primed in this fashion. Bonus question: why wait until after checking fuel quality before doing an early prime?

Airplane batteries are not made for deep cycling. This means that if you severely draw an airplane battery down a few times, it's ready for the trash heap because it will never again hold a charge. (Cruising sailboats have deep-cycle batteries because they are drawn on for many hours between engine operation when the battery is recharged. Automotive batteries will fail after about 30 deep cycles whereas they will last for thousands of cycles if only used for starting, a 2-5% discharge. Marine batteries are designed to handle 80% discharges over and over.). If you find this topic electrifying, see http://www.windsun.com/Batteries/Battery_FAQ.htm.

If you have cowl flaps and it is a cold day, don't open the cowl flaps during start, taxi and run up. Most manufacturers state something to the effect: open cowl flaps as required. Watch your temperatures. Cowl flaps are required with high cylinder head and oil temperatures, not likely for a first start of the day and several minutes after on a 40 F. morning. With the cowl flaps closed, your engine oil will heat faster. Run ups should be done with the oil temperature needle in the green and this can take time with a cold start on a big engine especially on a cold day. When you cycle the prop you are making sure the governor and prop are functioning and at the same time applying warm oil to the prop hub cylinder. That oil isn't going to be very warm if you do the prop cycle with cold engine oil. (I won't get into the religion of prop cycling during run up)

Be kind to your engine and it will be kind to you (and your wallet).