Archive for the Aeronautical Knowledge Category

Flight Range Ring is Always a Circle

Robert Chapin
2015-06-17T22:11:56+00:00
Concentric flight range rings with wind.

Even with a strong wind, the range ring is a perfect circle.

I found an interesting error in Flying Magazine today, in which the author described an airplane’s range as being “anywhere from a perfect circle to an egg shape based on the wind conditions.”  Wrong!

Remember, one should think in the most simple terms about the effect of wind on an airplane.  Wind is just motion of the air.  After an airplane leaves the ground during takeoff, it experiences no relative influence from a steady wind because the airplane is flying into the air in a manner that is constant relative to that air.  From any given point in the air mass, the airplane’s range is a perfect circle within that mass.

Wind is important in flight, of course, because it modifies the ground track and speed relative to the Earth’s surface.  This changes fuel requirements, and ultimately the cost and efficiency of flight between points on the surface.  But what the wind does not do is create “eggs” or “semi-oval shapes”.  When the wind is calm, the range circle in the air mass is identical on the ground.  When the wind is 20 kt, the center of the range circle moves 20 NM away from the airplane’s initial position on the surface for each one hour of flight.

The slight asymmetry of two or more range circles is created by the fact that concentric “range rings” will be centered in different positions on the surface.  As described above, if a 1-hour range ring is offset by 20 NM, then a 2-hour range ring must be offset by 40 NM, and so on.  When these range rings are plotted simultaneously, they give a slight illusion of being oblong, when in fact they are still perfectly circular.

If that explanation is too simple, you can verify the wind calculations using some basic high school trigonometry.

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17 Jun 2015

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GPS Flight Planning – WAAS Going On?

Robert Chapin
2015-04-23T23:16:08+00:00

Symbol for Alternate Minimums Not AuthorizedIt’s time to review the rules for planning an IFR flight with GPS navigation.  Maybe the airplane has an old receiver without WAAS capability.  Or maybe the rules have changed too many times to remember the current limitations.  Where to find the answers?

Destination Alternates – Without WAAS

I’m starting with destination rules, because most flight plans begin with that basic question:  Where to go and how to get there?

2013 – If you were aware of these rules a couple years ago, you knew to look them up in Published NOTAM No. GEN13000.  That notice expired in 2014.

2014 – AIM 1-1-18(g)(1) superseded the obscure notice, making the alternate airport rules somewhat easier to find.

2015 – The published 2015 FAR/AIM is already obsolete because the rules changed again on 8 January 2015.  Now, one must look for AIM 1-1-18(b)(5)(c).

I found four basic rules for flying GPS without WAAS:

  1. Pilots “may file based on a GPS-based IAP at either the destination or the alternate airport, but not at both locations.”
  2. Pilots may plan for LNAV or CIRCLING minimums only, unless equipped for baro-VNAV.
  3. A preflight RAIM prediction for the destination or the alternate airport is required.
  4. Language left over from AIM 1-2-3(d) and Notice N 8900.218 indicate the non-GPS approach at the other location is required to “be flown without reliance on GPS.”

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23 Apr 2015

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Re-Thinking Risk Assessment

Robert Chapin
2016-12-24T12:51:16+00:00

Assessing Risk, image from Risk Management HandbookThe best tool available for pilots to quantify overall flight risk is the form found in the FAA’s Personal and Weather Risk Assessment Guide.  However, that form is more than 10 years old and needs many improvements.  It is based on the “PAVE” method or checklist, and enables a pilot to assign a predetermined point value to each area of risk.  This helps to minimize subjectivity and encourages detailed preflight planning.  Using this process in connection with Aeronautical Decision Making is a great idea, but I want to illustrate several ways to make it more complete and hopefully more accurate.

PDF Icon Flight Assessment Form Download (29 KB)

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1 Feb 2015

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Missed Approach Points in Jeppesen Charts

Robert Chapin
2016-12-24T13:19:26+00:00
Legend for the missed approach point symbol.

Jeppesen Chart Symbols

The M.A.P. Study Guide is a list of notes I first developed during instrument-flight-instructor training because I needed a concise explanation of various approach profiles.  Now that I’m considering airline jobs, I’ve decided to adapt my study guide to the chart format used by Jeppesen, which is also used by many airlines.  I find the missed approach procedures slightly more intuitive in the Jeppesen format, but it also presents more information that can become overwhelming at first.

PDF Icon Study Guide Download – Jepp Format (1.2 MB)

You might also want the FAA charts format of the study guide.

Introduction

Reading a missed approach procedure is a critical step toward briefing and flying a complete instrument approach to an airport.  The missed approach point is the position where the pilot must immediately climb away from the airport if the landing criteria of FAR 91.175(c) are not met.  There are two challenges involved in reading the missed approach point:

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1 Jan 2015

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Engine Failure with Runway Remaining

Robert Chapin
2015-05-04T16:03:47+00:00
ATSB said most immediate forced landings do not result in serious injury.

ATSB said most immediate forced landings do not result in serious injury.

One of the most intimidating parts of flight training is the unlikely possibility that a single-engine training airplane could develop a single engine failure, thereby leaving no other engines available to help bring the airplane to a safe landing position.  While engine failures and emergency procedures are widely discussed and practiced within the general aviation community, not all emergencies are created equal.

It seems I may be teaching a relatively obscure maneuver: The engine failure that occurs after liftoff but before passing the departure end of the runway.  It’s not an engine failure during multi-engine training, not an engine failure in the pattern, and not an “impossible turn” situation.  I’m talking about a loss of thrust right smack in that precarious transition from ground effect to a sustained, best rate climb.  I use the word “obscure” here because I have looked through every guide for maneuvers, FAA handbooks, airplane manuals, and online training resources that I could find, and not one of them contains a detailed description of this maneuver.

I am writing this article for the benefit of flight instructors and single-engine pilots everywhere, and it comes with a big disclaimer:  My detailed procedure is not an adaptation of other work and is not based on existing procedures.  If a more official procedure existed, I would use it!  The information below might not be appropriate to your aircraft, and this procedure should never be attempted in an aircraft without a flight instructor.

Below the fold, you will also find a video that shows a very bad example of what this maneuver looks like when it is practiced without careful consideration for safety or personal minimums.

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8 Nov 2014

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Missed Approach Point Study Guide

Robert Chapin
2016-12-24T15:20:14+00:00
Legend for the missed approach point symbol.

FAA Chart Symbols

The M.A.P. Study Guide is a list of notes I first developed during instrument-flight-instructor training because I needed a concise explanation of various approach profiles.  Now that I am instructing instrument students, it seems this guide is the best tool for teaching missed approach identification with FAA charts.  The Missed Approach Point and Missed Approach Track symbols on each chart profile can mean different things depending on the type of procedure.

PDF Icon Study Guide Download – FAA format (2.8 MB)

You might also want the Jeppesen charts format of the study guide.

Introduction

Reading a missed approach procedure is a critical step toward briefing and flying a complete instrument approach to an airport.  The missed approach point is the position where the pilot must immediately climb away from the airport if the landing criteria of FAR 91.175(c) are not met.  There are two challenges involved in reading the missed approach point:

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13 Nov 2013

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New Circling Procedures in Michigan

Robert Chapin
2015-04-23T16:22:42+00:00

New approach minimums format.Starting with the current chart cycle from August 22, the radius of protected airspace for new circling approach procedures has increased.

This change will mainly affect airplanes in approach categories B through D.

While the procedures are flown in the same way, the requirements for a larger protected airspace may result in higher altitudes being flown.

For example, if your destination is the Traverse City (KTVC) GPS RWY 36 approach, the category C minimum descent altitude (MDA) has increased from 1,280 ft to 1,500 ft.  The category D MDA changed from 1,300 ft to 1,720 ft, and so on.  The good news is that this approach was also revised to include an LPV descision altitude of 898 ft.

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2 Sep 2013

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CFIT Training Aid

Robert Chapin
2016-12-24T15:14:24+00:00

Controlled Flight Into Terrain Education and Training AidControlled Flight Into Terrain (CFIT) prevention is one of the main topics of Single-pilot Resource Management (SRM).  As a pilot, I do want to avoid flying into terrain!  I also enjoy studying any aspect of aviation.  Sometimes this means tracking down an obscure publication, and I do enjoy that challenge as well.

I found several mentions of a document named Controlled Flight Into Terrain Education and Training Aid from around 1996.  However, something has gone buggy in the FAA website, and there is no obvious way to find the document.  It looks like someone copied an old CD-ROM to the website and expected it to work without any modernization.

As a service to the aviation community, I have painstakingly reverse-engineered, scraped, edited, and re-assembled the more than 500 individual files to create an easy-to-download version on a single link.

PDF Icon CFIT Training Aid (40 MB)

Important note: The original document was approximately 914 pages long and I have been unable to find at least nine of those pages.  I am also missing the original video.

21 Aug 2013

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The Runway Incursion Avoidance Task

Robert Chapin
2013-01-30T00:25:32+00:00

Page 1 of the new PHAK chapter.I just learned that the FAA published critical safety procedures back in April pertaining to the new runway incursion avoidance standards for pilot testing.  This is a surprise to me because I’ve taken several tests since April.  According to FAA Safety Notice NOTC3863, which I recently surfed into, that new information was removed from the public list of  notices in August.

Here is the critical bit:

A New Chapter has been added to the Pilot’s Handbook of Aeronautical Knowledge (PHAK) entitled, Runway Incursion Avoidance. This chapter, contained in Appendix 1, provides the information pilots will be tested and checked on.

This is where it gets weird.  I went to update my copy of the PHAK today, but found the 2008 version is still the latest copy on the FAA website.  I had also checked for updates in May, August, and October this year, and only found the 2008 version.

A new chapter has been added to the PHAK.  But it hasn’t.  To get the new chapter, you have to visit the link above, or download it directly from PHAK Appendix 1.  I hope the FAA will notice the problem and update the PHAK information. (The PHAK page was indeed updated on 11 Jan 2013 and now it includes the extra link.)

I will take notes from the new material and include them below.  One of the more interesting points is that the runway hold-short position might not be where you think it is!

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29 Dec 2012

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FAA Airplane Categories

Robert Chapin
2014-03-09T14:31:40+00:00

Aircraft categories, with respect to the certification of aircraft, are defined as “a grouping of aircraft based upon intended use or operating limitations.”  This is a topic in need of disentanglement.  I will focus on airplane categories to establish a concise point-of-reference.

Before today, searching for this information could be very frustrating because, officially, it falls under the heading of “Airworthiness certificates: classification,” better known as 14 CFR § 21.175.  This is the only place I could find all eleven categories mentioned.

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20 Jan 2012

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