Ask a Flight Instructor

From all of us at askacfi.com, ‘Happy holidays to all, And to all a safe flight”

Charles, a 2000+ hours ATP asked the following:

“Hi, I have a question about GPS approaches. Why are LNAV and LNAV/VNAV minima different on RNAV GPS Approaches?”

Great question Charles. Things are changing so fast in the GPS world that it’s hard for instrument pilots to keep up with all of the new acronyms and just what they mean. But you want to understand them before you’re stuck in the clouds, furiously twisting knobs, while hoping to avoid an encounter with a cumulo-granite cloud (Ouch!).

I’m going to be self-serving–since it will save me a lot of typing–and quote directly from two of my books and CDs. Many readers may not be familiar with LNAV/VNAV minimums for a GPS approach, so let me quote from my new Max Trescott’s GPS and WAAS Instrument Flying Handbook (which I might add would be a great Christmas gift for pilots to buy now for themselves!):

“As previously mentioned, airliners with special equipment fly to LNAV/VNAV minimums and now you can too with a WAAS-capable receiver. From a practical standpoint, however, you’ll probably use these minimums only on the handful of approaches for which no LPV minimums are designated, since LNAV/VNAV minimums are almost always higher than LPV minimums. In very rare cases, LNAV/VNAV minimums can be lower than LPV minimums, due to differences in how obstacles are evaluated for these approaches. So surprisingly, a GA pilot’s WAAS-capable receiver that can fly to LPV minimums is far more versatile than many airliners’ equipment, which cannot go lower than LNAV/VNAV minimums. Like LPV minimums, LNAV/VNAV minimums are specified with a DA or decision altitude.”

Charles, you wanted me to contrast that with LNAV minimums. Let me briefly explain to readers that LNAV, which stands for lateral navigation, is the tradition minimums to which we’ve always flown GPS approaches. Originally there was only one minimums type for a GPS approach, so those minimums didn’t need a name. Now that there are 5 different minimum types available for GPS approaches, the original ones needed a name so they’re called LNAV. LNAV minimums are basic, non-precision minimums. Just fly to the MDA (minimum descent altitude) specified and don’t go an inch lower than that altitude!

Now we need to know how what pilots call the “protected area” differs for LNAV/VNAV and LNAV minimums. This time let me quote from the audio track of one of my computer courses, Max Trescott’s WAAS and GPS CD-ROM Course (another great gift idea for a pilot to get him or herself for Christmas).

“Let’s talk briefly about the protected areas for LNAV/VNAV approaches. First, the horizontal protected area is the same as that used for constructing a LNAV approach, so the equipment required to fly these approaches only has to meet the TSO-C129a, which is the standard for non-WAAS capable receivers. Since the navigation will therefore be less accurate, larger protected areas are needed than for an LPV approach.”

Now we know that the horizontal protection areas are the same for LNAV/VNAV and LNAV minimums. So essentially your question would be identical to “Why are the minimums different between an ILS and a localizer approach.” The answer is of course the glide path (or in the case of an ILS, the glide slope). Non-precision approaches resemble the steps in a flight of stairs and pilots can immediately descend down to the next altitude at each step. But the glide path of a RNAV (GPS) approach more close resembles the handrail for a flight of stairs. It provides a smooth, continuous descent path. The glide path can be designed to avoid obstacles that might force a higher MDA for a non-precision approach. So the answer to your question is that LNAV/VNAV minimums are usually lower than minimums LNAV minimums since it incorporates a glide path, helping it avoid some obstacles.

A couple of months ago, I shared with you some illustrations that I found on the back cover of some older FAA Aviation News. These illustrations were done by the illustrator and cartoonist Robert C. Osborn. Little did I know that finding and preserving more of these illustrations would turn into my new hobby.

Since my first Osborn post, I have learned a great deal about the artist and his other work. I’ve learned that Osborn contributed to FAA Aviation News for nearly 25 years from the early 60s to the mid 80s. I’ve also learned that Robert Osborn was the creator of the first and original “Dilbert” cartoon character. Osborn drew nearly 2,000 safety posters for the Navy during WWII that featured “Dilbert the Pilot” and “Spoiler the Mechanic”. Dilbert and Spoiler were both the ambassadors of carelessness and recklessness. “Don’t be a Dilbert” was a popular phrase used among pilots to encourage others to think about safety continuously.  Did you know that the popular comic strip Dilbert actually borrowed it’s name from the Dilbert drawn by Osborn?  According to Scott Adam’s blog, the name Dilbert was given to him by a co-worker who later confessed that he saw the name on some of his dad’s military memorabilia.

As I promised earlier, here are some more Robert Osborn illustrations from the FAA Aviation News. You’ll notice a theme with these particular illustrations…winter flying! Unfortunately, that season is upon us and it’s time that we all started thinking about the dangers and complications of flying in icing conditions.   This would be a great time to grab that POH and look over cold winter operation notes and any other limitations that colder weather may pose to your upcoming flights.

Fly Safe (and enjoy)

Flying in a new or different airplane is always fun.  Such is the case with Jacob who had the joy of flying in his friend’s Mooney.   Unfortunately, the technique that his friend used to start the Mooney’s engine left him a little confused about starting techniques so he writes in asking:

I was flying in a friends plane the other day, a Mooney Ovation 2gx. When he started the airplane he had full mixture, with his hand on the throttle and the ignition. I didn’t ask him why the plane starts that way. I fly a 172. Whats the difference? Why do you start the 172 the way you do(prime, mixture lean, then upon starting full rich)? Would a “mixture full rich” start work on a 172?  Just curious.

Hi Jacob,

Aren’t Mooneys great? I’ve had the opportunity recently to fly a Ovation 2GX once as well. Man, was it a FAST airplane. Mooney’s really do seem like the “Porsche” of the general aviation fleet. Very slick.

There are obviously a lot of differences between your airplane, a Cessna 172, and your friend’s Mooney (as I am sure you noticed). However, I am a little curious about the starting technique that you use in the Cessna.  I’m going to assume for a second that you have a carburetor equipped Cessna and every carb equipped Cessna I’ve ever flown in you DO start with the mixture in full rich.  I am sure your instructor or FBO has a good reason why you start your particular airplane leaned out, but without further information about your particular model 172,  I can’t really tell you much more.  The only exception to a full rich start that I know of is a hot start or when attempting to start at an high altitude airport.   In both cases, you want the engine leaned out to prevent flooding due to the decreased density of the ambient air.

If in fact you are not a high altitude airport or conducting hot starts, then I’m a little worried about the condition of your carburetor.  It might be worth checking out the condition of your float.   The FAA just released a Special Airworthiness Information Bulletin on October 16, 2009 that addresses this exact issue.  You can check out the Airworthiness Bulletin for yourself at FAA.gov.  The service bulletin is NE-10-05 and the subject is “Control/Reciprocating Engine – Float-type Carburetors”.    This bulletin recommends that pilots “examine the engine area for evidence of fuel leakage.  During engine start be alert for carburetor flooding or the need for excessive leaning.  Hard starting might be an indicator of a deteriorating or damaged carburetor float”   The service bulletin also warns that “improper metering of fuel or fuel leaking from the carburetor…can lead to complete loss of power or engine fires.” I’m not saying that there is something wrong with your engine (especially if you are at higher altitudes or practice a lot of hot starts) but it might be worth checking out.

Feel free to respond with any particularities that might help us figure out why your aircraft engine starting technique is a little different.

UPDATE: Shortly after posting this article I have received several comments about the starting procedures on the newer fuel injected Lycomming engines.  I haven’t flown one in a while and forgot that yes, you do indeed start with the mixture leaned and slowly increase the mixture during the start sequence.  Why Lycomming and Continentals have different starting techniques is inherent to the design of the engine.  I’m still looking up specifics and will post this information when I find out more.  Still, if you have a carb equipped C172 and are starting full lean, you might need to get something checked out.

Fly Safe.

Kent wrote me this morning asking:

While flying recently with my friend a question came up which has come up for me several times in the past. I firmly believe that while flying VFR practice approaches (as published) into an uncontrolled airport that radio communication with the controlling ATC needs to be made-I always thought the approached as published is their approach. My friend firmly believes that as long as it’s VMC and uncontrolled airspace that one does not need to be talking to ATC. I do agree that it seems to be common practice to fly these on your own without ATC but is this really appropriate/legal?

Hi Kent,

This might be one of the cases where what is legal isn’t necessarily safe. The safe thing is always to contact ATC and request flight following / radar services when practicing any kind of approach.  Remember, that’s why they are there (and for now it’s still a free service). Even if you aren’t receiving radar services it would be prudent to at the very least monitor the appropriate frequency.  The reasoning of course is that if an airplane comes along that really does need to shoot that approach (corporate, airline, etc), your presence on the approach might make the required IFR separation difficult if not impossible for ATC.   Also, having that second (or third set) of eyes is always a good backup in case both pilots become preoccupied with the technicalities of the approach.  How sad would it be if ATC could have stopped the collision of 2 VFR aircraft…if only they were talking to them!  That brings up another point too, what if there is another aircraft on the same approach that has a pilot with the same mentality of your friend?   Now you have 2 VFR airplanes, practicing the same approach and neither of them are talking to ATC…that’s just asking for something to happen!

However, according to the AIM Chapter 3 Section 2, in uncontrolled airspace or class E (as I’m guessing your approach is in) there is no communications requirement for VFR aircraft.   I find nothing else published saying that you have to establish contact with ATC just because you are on a segment of an instrument approach.   Technically your friend is right but that doesn’t mean that would be the safest operating practice (I’d rather be safe and alive then dead and right).

As a pilot (and PIC) you have every right to stand up for yourself and establish your own operating procedures.  Let everyone you fly with know that your rule is to contact ATC on VFR practice approaches.  Don’t let yourself be lead down the path of least resistance!  A good pilot listens to his gut. If something doesn’t feel right, STOP!  Don’t continue.  Figure out what you don’t like about the situation and correct it.  If you don’t like practicing approaches without contacting ATC, then don’t do them!  There are plenty of times in my career where I’ve had to stand up for a situation I thought was unsafe, even if it was “legal” to continue.

Fly Safe.

Bill writes me asking:

How do I select a flight instructor? I’m 49, good health, been around aircraft my whole life and finally beginning to find the time to learn.

Great question Bill. Choosing the right flight instructor is the first step in a successful flight training experience.  Your flight instructor will influence your attitude and approach towards all your future flying.   It is important that you take some time and choose an instructor wisely.  I’ve had a few flight instructors since I started flying and most of them have been great and some…well, not so much.  Here are couple recommendations to avoid the later:

I would begin your search by visiting local area airports.  Most airports have a flight training program available and many airports have several flight schools to choose from.  You’ll notice that flight schools are typically located at an FBO (fixed based operator).  An FBO is the business at an airport that provides services such as fuel, maintenance, hangar rental and flight training.  I would recommend calling the schools ahead of time and asking some general questions to get a good feel for the school. Here are few questions to get you started:

• What type of flight school is offered?  Flight schools are broken down into 2 categories:  Part 61 or Part 141 (accelerated).  If you are in a hurry and plan on pursuing multiple certificates within a short time period you’ll want to focus your search for a flight instructor at a Part 141 accredited schools, otherwise an instructor at a Part 61 school would be just fine.
• How many instructors are there? The more instructors a school has  the better chance that you’ll be able to find an instructor that has availability and a similar schedule as you.  Many instructors (especially in today’s environment) have an additional job besides flight instructing, so you’ll have to make sure the schedules mesh.
• How many training airplanes do they have?  Again, if a flight school only has 1 airplane, there is a good change it will be flying all the time which makes it harder to schedule your lessons and also harder to schedule re-flights in case a flight gets canceled due to maintenance or weather.
• What flight training courses are offered?  If you find a good flight instructor or a school that retains good flight instructors, you might want to pursue additional ratings and certificates after obtaining your private pilot’s license.
• What about the costs?  You’ll want to make sure you ask about both the airplane and flight instructor rates.  Typically, a flight school will charge one rate for flight instruction and another rate for ground instruction.  Be sure to ask about both.

Once you have some preliminary questions answered, make a list of the schools or airports that meet your criteria and start planning some visits.   I would recommend visiting during the week (if you can) as you’ll have a better chance of meeting the chief instructor or catching an instructor between flights.  A good chief instructor will want to sit down with you and discuss their program and your schedule.   The instructor you meet with might be even be able to suggest another instructor that has a similar schedule as you. Extra tip!  When you are in the parking lot of the school try and get a recommendation from another student that might be going (or coming) from a flight.

After visiting several flight schools, narrow your list down to no more than 1 or 2 schools.  Call these schools and schedule an “introductory flight”.  This flight consists of a casual half hour flight in the local area.  Try and schedule this flight with the instructor who was recommended and that you are considering.   During your flight, try and get a sense of the instructor’s professionalism and teaching style.  Here are some more questions to consider:

• Was the instructor on time to the flight?
• How was the instructor dressed?
• Does the instructor seemed organized?
• And most of all, do you feel safe?  Is this someone you would let take your kids or spouse on a flight?

If you don’t feel comfortable with this instructor, don’t schedule any lessons until you’ve flown or talked with an instructor you do feel comfortable with.

An important note: Once you have chosen an instructor, you are allowed to change.  This isn’t a marriage and choosing a new instructor does not constitute a divorce.  It is best obviously to stay with one instructor through a course or program but if for some reason you and your instructor aren’t “clicking” then it is recommended to find a new one.  For some, this can be a bit awkward to do, but it is important to understand that at the end of the day, you are the paying customer and as a customer you deserve to be satisfied with the services you are receiving from the school or instructor.  I have been on both ends of this for as a student pilot, I had to request a new instructor and as an instructor, I have had to recommend that a student continue his program with an another instructor.

There are a couple of online resources to help you in your search:

• Flight School Reviewer.com This site is a source for current or ex students of particular programs to offer written reviews of flight schools they attended.  Not all flight schools have been reviewed (there are thousands) but there are several that have received reviews and it might be worth checking out.
• NAFI. NAFI is the National Association of Flight Instructors.   NAFI offers a “Find a Flight Instructor” feature on their site.  You can search for a “Master CFI” which is a nationally accredited designation for those flight instructors that have reached “the highest level of instructional activity, educational experience and professional service”.  Not all flight instructors are NAFI members, but many professional and career flight instructors are NAFI members.
• AOPA.   The Aircraft Owners and Pilot’s Association has several tools and tips for choosing a flight instructor or school.  They offer both “Find a flight school” and “Find a Flight Instructor” as well as the article “How to choose a flight school / instructor“.

During preflight this morning I came across an interesting NOTAM:

SGH 11/011 SGH AIRSPACE HIBAL SGH202011 E BND REACHING FL600
WEF 0911141600-0911141800

So what does HIBAL stand for ?

HIBAL is the Notam contraction for high altitude balloon. Most likely, a National Weather Service balloon with radiosonde.   A radiosonde is a small device that is suspended about 80 feet below a 6 foot hydrogen or helium balloon.  The radiosonde consists of sensors and a small radio transmitter.  The sensors are able to read temperature, pressure and relative humidity.  The on board transmitter sends this data back to sensitive ground based equipment for recording.  By recording the GPS coordinates (if equipped) and the direction of the data using radio directional finding antennas, it is also possible to record wind speed and direction.

To learn more about Radiosondes and their uses, NOAA National Weather Service has put together this radiosonde fact sheet.

Back to the NOTAM:

SGH 11/011 SGH AIRSPACE HIBAL SGH202011 E BND REACHING FL600
WEF 0911141600-0911141800

This NOTAM says that between 1600 Zulu and 1800 Zulu on the 14th of November, a high altitude balloon (HIBAL) is being released on the SGH VOR radial 202 at 11 DME (202011).  The balloon is expected to go east bound and reach 60,000 feet (FL600).

Fly Safe.

Robert wrote me this morning asking:

I stopped flying over 20 years ago and would like to start again. What do I need to do to get reissued my license?

Hi Robert,

First off, congratulations on making the decision to start flying again. There have been some really neat advances in technology since 1989, especially in avionics. If you get the chance to fly a newer airplane, it’ll blow your socks off!

There are 4 different federal aviation regulations that pertain to your question:

1. § 61.19 Duration of pilot and instructor certificates
2. § 61.2 Exercise of Privilege
3. § 61.23   Medical certificates: Requirement and duration.
4. § 61.56 Flight Review
5. § 61.57 Recent Flight Experience : Pilot in command

I know it sounds like a lot of boring legalize to go through, but it’s really not that bad. Let’s take these one-by-one and then make a plan-of-action to get you back in the cockpit.

Read the rest of this post by clicking the “continue” link:

Read the rest of this entry »

Here is a question from a new CFI concerning practicing approaches with a student pilot:

I am a new CFI-A, and currently finishing up one of my first students. While just buzzing around with the student under the hood performing unusual attitudes, climbs/ descents and turns, I would like to introduce to my student a little bit of the instrument approach procedures. To me it seems a little bit better with “If you enter IMC while VFR, here is how you can get out…” Can I do this as just a CFI-A and not a CFII-A?

This is a great question, and one that I’m sure a lot of newly minted CFIs have wondered.  There are actually two different approaches to this question.  First is the legal answer (what can you do) and second is the prudent answer (what should you do…IMHO).

Legally

According to 61.109 (Aeronautical Experience) Private Pilot applicants are required to have 3 hours training of simulated instrument training.  Here is the current wording:

3 hours of flight training in a single-engine airplane on the control and maneuvering of an airplane solely by reference to instruments, including straight and level flight, constant airspeed climbs and descents, turns to a heading, recovery from unusual flight attitudes, radio communications, and the use of navigation systems/facilities and radar services appropriate to instrument flight;

While it doesn’t specifically say “instrument approaches”, I think most people would consider an instrument approach procedure to be practicing the use of a navigation system or facility.  Also, while you are receiving vectors for an approach, you would be reviewing “radar services” right?

The other regulation to consider is the flight instructor privileges and limitations.  For this, we look at 61.195 subparagraph (c) which specifies when a CFI must have a instrument rating (on the flight instructor certificate):

(c) Instrument Rating. A flight instructor who provides instrument flight training for the issuance of an instrument rating or a type rating not limited to VFR must hold an instrument rating on his or her flight instructor certificate and pilot certificate that is appropriate to the category and class of aircraft in which instrument training is being provided.

So as long as the instrument training you are providing is not for the issuance of instrument rating, then yes, I believe you could practice instrument approach procedures with your student pilot.  But should you?

Prudently

I would highly suggest that you not practice approaches with a student pilot.  And here is my reasoning:

Inadvertent IFR or VFR into IMC accidents are still a huge problem area for General Aviation as the current AOPA Nall report indicates.  (see chart) The solution however isn’t found by introducing primary students to complicated approach procedures.  The solution is teaching students 1) how to avoid getting into this situation altogether and b) how to overcome disorientation, maintain aircraft control and get the assistance from ATC that they need to find VMC conditions.

Sudden fear and panic is the feeling that will grip your student if they accidentally encounter IMC during a flight.  It is imperative that your student know how to maintain positive control and how to request assistance from ATC.

And that’s the other thing, if ATC is contacted by a VFR only pilot who is stuck in accidental IMC, ATC is not going to entertain the thought of that student shooting an approach (unless absolutely necessary and even then probably a radar approach).  ATCs’  focus and task will be on getting that pilot back to VMC conditions so that the pilot can visually acquire a airport and land.

I would also be nervous about introducing this to my student for fear that they might use this knowledge to overestimate their own ability which could lead to a false sense of confidence.  I could just hear my student thinking, “Weather isn’t that great at my destination, but Ill be fine if does deteriorates because I know that if I really really had too, I could do an instrument approach.”

Again, I would suggest using the required 3 hours with your student to thoroughly cover the basics of instrument flight.  Make sure they know and understand that maintaining aircraft control is critical and that ATC is there to help steer the pilot back to VFR conditions.

“Safe to Solo – What every young aviator should know” by Frederick M. Reeder and Robert C. Osborn.  This was published by Harper and Brothers in 1947 (now HarperCollins) but I dare you to find anything in the following paragraphs that isn’t true today.  If you read nothing else on this entire site, please read and think about the following paragraphs.  Your life may depend on it:

Aviation is safe.  It is also safer for some than for others.  The papers say that foolproof planes have been invented and soon everyone will take to the air.  Doubtless this is so, and in the not too distant  future everyone will fly, especially that fool who is going to disprove the foolproof airplane.  Flying is much safer today than it was even a few years ago, and it will become safer and safer as time passes.  However, airplanes are still machines and no one has successfully trained one to think yet.  That is supposed to be where the pilot comes in. If he doesn’t think or is unable to, he is a bad risk regardless of how smart his plane is.

It would be nice if we could tell you that aviation has now reached the point where it is so completely safe that there are no accidents, that you don’t even have to consider safety because that has all been worked out for you by someone else.  However, that is not the story and it never will be.  You must become safety-conscious.  Not so much that you worry yourself or go around tense with fear that something awful is going to happen.  It won’t if you learn to take proper precautions and can think.  You probably have noticed that the word “dangerous” appears frequently in this book, that there are many cautions and warnings regarding safety.  All of these have been derived from personal experience or that of close friends.  When you come across those portions, it will be a good idea for you to keep the subject matter in mind and review it from time to time until you understand it.

…We used to speak of the “Automatic Eliminator” which got rid of the poor pilots.  Not those who were slow learning; those who shouldn’t be flying at all.  Perhaps the foolproof plane will help them some, but the “flying fool” is a dangerous breed and should be avoided like the plague.

Remember that about 80 percent of all aviation accidents are caused by pilot error.  Sometimes accidents can’t be avoided.  However, if you are alert and understand what you are doing, you can probably avoid them entirely.  If you go around showing off in your plane, your chances of having an aviation accident increased immeasurably – leave it alone.

Please, fly safe.