Archive for November, 2011
Visual Flying Steep Turns
Posted by wbeard52 in Visual Flying Techniques on November 19, 2011
This was written originally by me on the SkyVector Forum. I’ve decided to place all of my writings on my blog. This will be a part of a visual flying technique series I am working on.
Steep turns were one of the maneuvers I found to be difficult as a student pilot. As a student pilot, I was convinced that I needed to continually watch the flight instruments in my attempt to remain within the Private Pilot PTS standards. It wasn’t till after the practical test that I realized a much easier way of performing steep turns. It just so happens that In instrument training there is a lot of talk about attitude instrument flying but no one ever told me about attitude visual flying and my private pilot flying showed it. This method will make steep turns a purely visual maneuver, which is what the maneuver is supposed to be. I now teach my students to only look inside four times during a turn at each 90° turn.
The easiest way of performing steep turns is to keep the eyes outside the airplane 95% of the time. First setup the airplane; place the nose on a reference point outside the airplane, glance at the altimeter and ensure it is on the assigned altitude and place the nose outside in level flight. In the picture above there is no doubt the plane is headed directly for the mountain top. If the airplane starts pointing directly to the mountain top and end pointing at the same mountain top there is no need to look at the heading indicator to see if you are with PTS standards (±10°). You will be right on.
To get the airplane in level flight outside the airplane you will need to be able to reference something on the airplane with something outside the airplane. In a small aircraft I use the top of the cowling and the earth horizon. Typically, 3-4 fingers between the cowling upward to the horizon will keep level flight.
As you start the steep turn, smoothly apply aileron and rudder till the airplane outside appears to be at 45°. At this point neutralize both controls and glance at the attitude indicator. Immediately pitch up and place the nose of the aircraft on the horizon. Glance at the altimeter to ensure level flight. You may need to add some opposite aileron (small amount) for the overbanking tendency. Notice the two separate maneuvers involved here. The first maneuver is to establish the 45° bank and the second is to pitch up to correct for the loss of vertical lift
If you trim out the airplane, the aircraft should stay at the flight attitude you just setup. If done correctly, the controls can be let go of and you can watch the airplane stay in that flight attitude. Monitor the instruments once every 90° of turn for 1 second to ensure the aircraft is staying inside the PTS standards.
When your previous reference point comes back into view, smoothly apply aileron and rudder to place the nose on the reference point and place the nose again about 3-4 fingers below the horizon. Retrim as necessary.
Steep turns requires the student pilot to be proficient in visual flying (flying purely outside the aircraft), coordinated turns, and proper trimming procedures. This method will introduce a different concept about visual flying. In side-by-side aircraft, the student pilot will perform the steep turns correctly to the left and descend on the right turn due to the reference point on the cowling not being in the middle of the cowling. To correct this, a discussion on parallax should occur.
A smart writer for AOPA Flight Training Magazine, Ralph Butcher has a very good article explaining how his flight school teaches private pilot students. His method is to cover up all the instruments and not to even reference them until the last couple flight before the private practical test. I am not there yet but I like that direction a whole lot more than a generation of pilots looking at their instruments and only occasionally looks outside.
Understanding Weather Reports
I was standing inside the airport terminal and rain was pouring down outside on the tarmac. I figured this would be a good time for a teachable moment with my student who just got inside from pre-flighting the aircraft when the down pour started. I pulled out my cell phone and called the local AWOS phone number to get an updated weather report.
I could almost repeat what the weather is going to be like, very strong winds with gusts a lowered visibility and very heavy rain. What I got, my to my dismay on the teaching moment, was strong winds with no gusts and only light rain. Both my student and I looked at each other puzzled and he asked me why the AWOS weather was not correct. I said, honestly, I don’t know.
A few minutes later, the storm moved quickly through and the wind calmed down and only light rain was falling. I thought to myself and wondered what the AWOS would say. Winds very strong and gusting with heavy rain. TO say the least, I lost my teaching moment and promised my student I would figure out what this all means. I was hoping the AWOS system was out of tolerance and needed repair but that was not the case. A review of AC 00-45 Aviation Weather Services shed clues on what I was missing and it may be interesting to you as well. I was also able to get a copy of the OFCM Surface Weather Observations and Reports Handbook.
Did you know that most of the weather listed above is averaged over a given period of time? If the weather is changing quickly enough, the newly received weather from the AWOS system may be obsolete as it was in my case above. It begins to make you think about the accuracy of the weather for certain situations, doesn’t it?
For example let us examine the wind component. First of, we know that printed winds are always in respect to TRUE NORTH and spoken winds are always with respect to MAGNETIC NORTH (see note in AIM 7-1-10). Did you know the wind shown above is the average wind over the preceding two minutes? It may not even be accurate anymore but we can be assured the new wind is less than 60° from what it says. The VRB wind is used when the wind over the previous two minutes vary more than 60° and the speed is less than six knots.. A variable wind 060V150 is for speed greater than six knots.
A gust is a little more complicated is the AWOS / ASOS system examines all the wind over the preceding 10 minutes and will report a gust if a rapid fluctuation between low speed and high speed has a difference of 10 knot or more. It is quite possible that no gust exists any longer even though the METAR report is only one minute old.
A wind shift happens when the wind changes by 45° in less than 15 minutes with wind speeds greater than 10 knots.
The visibility group is pretty interesting. The weather report can be automated and / or manual by the tower. If it is automated, there is 10 minutes of sensor data used in the prevailing surface visibility.
The present weather group (in this case -RA) has a time frame associated with it as well. For example, over the previous six minutes, the accumulation rate is observed and reported in the METAR. It makes sense now why I first received a light rain when it was a heavy downpour and a heavy rain when it just stopped a couple minutes before.
There are also distance requirements for the prevailing weather group. If the prevailing weather is at the airport which is defined as with a 5 mile radius there is will nothing with prevailing weather as in our case above (-RA). If the prevailing weather is between 5 miles and 10 miles from the airfield, the code VC is used for “in the vicinity” like this: VCSH for there are showers in the vicinity of the airport. Weather greater than 10 miles from the airport uses DSNT for distant weather and is usually associated with lightening.
What does this all mean to me? I know that the currently reported weather may or may not have changed and I should be ready for anything that happens to show up. I much prefer to have a human observer to an automated station and will trust weather from a military station more than a civilian airport. As always, frequent updates from tower personnel is highly desirable.
