Saturday, June 23, 2012

ALERT! Federal aviation regulation requirement to operate on the airway center line may contribute to threat of mid air collisions!

"§ 91.181   Course to be flown.
Unless otherwise authorized by ATC, no person may operate an aircraft within controlled airspace under IFR except as follows:
(a) On an ATS route, along the centerline of that airway.
(b) On any other route, along the direct course between the navigational aids or fixes defining that route. However, this section does not prohibit maneuvering the aircraft to pass well clear of other air traffic or the maneuvering of the aircraft in VFR conditions to clear the intended flight path both before and during climb or descent."

The current Federal Aviation Administration regulation 91.181 requires pilots to operate their flights along the course centerline of their cleared routing.  I would like to suggest this may actually enhance the possibility  of a mid air collision occurring.  The reason for this is the recent availability of Wide Area Augmentation Systems for the Global Navigation Satellite System.  In addition, the European Geostationary Navigational Overlay System obtained fully operational status making the same accuracy of navigation available in European airspace.The accuracy of both these systems is plus or minus one meter, never worse than two meters.

An article written more than 50 years ago that appears in Wikipedia is entitled "The Paradox of Navigation," The author concludes that the "more accurately we navigate, the more likely mid air collisions will occur."

Also see a previous post on this Blog entitled "Randomness is Good!"

Pilot flight proficiency - Each pilot is individually responsible to maintain his hand flying skills. Period!

Airbus A-330 - Flight 447 Rio to Paris
Fatalities - 216 passengers, 12 crew
June 1, 2009

The crash of Air France Flight 447 on June 1, 2009 as well as the Colgan Air Flight 3407 Buffalo, New York crash  on February 12, 2009 has caused the subject of pilot  flight proficiency to be discussed with increasing frequency in the media. This has caused me to do some thinking about it and I have concluded that each pilot has the primary role in determining his level of proficiency in hand flying his aircraft.

Prior to each flight, the pilot should pose this question to himself and decide whether he is proficient to take on the tasks associated with the flight. If he decides his proficiency has suffered to the point where he is not proficient to take on the flight, he should remove himself from the flight.  He should request the necessary training to reestablish his hand flying proficiency.

How do you insure your hand flying proficiency is maintained? Only you know if you are proficient or not...  

There are already established regulations to make sure the pilot is proficient.  The regulations that come to mind are the minimum required instrument approaches to be accomplished in a six month period as well as the one that requires pilots to have a minimum number of landings before he can carry passengers. Both requirements are found in the Code of Federal Air Regulations, Part 61 CERTIFICATION: PILOTS, FLIGHT INSTRUCTORS, AND GROUND INSTRUCTORS, Section 61.57.

I personally ran into the question of my hand flying proficiency in my last two years of my career at Trans World Airlines.  I was very senior and able to hold a flight pairing that only flew nonstop to Tel Aviv, Israel from New York.  The schedule was only flown once per week.  This meant I only flew one leg per week or 4 times per month.  As a result, in order to maintain my hand flying proficiency I maximized the amount of time I actually hand flew the Boeing 747-100.

I would hand fly the aircraft for the takeoff and climb to cruise altitude and hand fly the aircraft at the cruise altitude for a period of time that might amount to a time of about 45 minutes to as long as an hour before reengaging the autopilot. When I reached the point when it was time to initiate my descent, I would disengage the autopilot and hand fly the descent all the way to the landing.

This enhanced my hand flying proficiency to such a degree that I was always able to answer the question as to my proficiency, with "Yes, I am proficient."

Reduced Vertical Separation Minima

In 1997, as the result of the implementation of Reduced Vertical Separation Minima, I encountered a conflict in my attempts to maintain this proficiency. As you may know, in order to operate under the provisions of the Reduced Vertical Separation Minima you should have the autopilot altitude hold engaged while in Reduced Vertical Separation Minima Airspace.  This includes the initial level off maneuver at cruise altitudes.

There is a provision that will permit me to disengage the autopilot if the aircraft is out of trim due to fuel burn off or changes in indicated airspeed or power changes.

 It is permissible to disengage the autopilot and retrim the aircraft manually and then reengage the autopilot when the trimming process is completed. I took some liberties with this provision in order to extend the time I was gaining proficiency in my hand flying skills.

The increasing emphasis on use of the automated capabilities of the aircraft computerized flight management systems is contributing to the lack of proficiency. In other words, there is in unintended consequence of following the fully automated operational practice. On some aircraft today, the standard operational procedures requires the pilot to engage the autopilot at 400 feet on takeoff and continue use of the autopilot all the way through the landing at the destination. Total time of hand flying under that procedure can be less than one and a half minutes.

How can a pilot using the autopilot in this manner  retain his hand flying skills?  It is impossible!
Please recall that a pilot in command is the final authority and responsible for the operation of his flight.  The Code of Federal Air Regulations  Section 91.3 states this very, very clearly.  He is authorized and able to take whatever action he determines operationally. See:

Title 14: Aeronautics and Space
Subpart A—General 

Browse Previous | Browse Next
§ 91.3   Responsibility and authority of the pilot in command.
(a) The pilot in command of an aircraft is directly responsible for, and is the final authority as to, the operation of that aircraft.
(b) In an in-flight emergency requiring immediate action, the pilot in command may deviate from any rule of this part to the extent required to meet that emergency.
(c) Each pilot in command who deviates from a rule under paragraph (b) of this section shall, upon the request of the Administrator, send a written report of that deviation to the Administrator.

I believe many pilots have misinterpreted the above words to cause them to believe it only applies to emergency situations.  The words do not say that to me. What do you think they say about the pilot in command's authority? Does it only apply only during an emergency?

By the way,
Acronyms Suck!!!
Thanks for taking the time to read this post and I would appreciate  your comments. Please note no acronyms were used in this post.  This was deliberate on my part.  I feel acronyms are not of value when attempting to communicate and especially in the learning process.  I would appreciate any comments from you concerning my effort to eliminate acronyms. Do you think acronyms should be eliminated?  If so, why? Or why not?

Knots are for boats!
And while I have your attention, I have been bothered by the change from miles per hour to knots for speed values for aircraft for more than 35 years.   Lets bring back miles per hour for aircraft.  For example, since most people reference speed using miles per hour, advertising a speed in knots for new aircraft is penalizing their perceived capability.

527 knots does not sound as impressive as 605 miles per hour.

Monday, February 13, 2012

Using the Global Positioning System (GPS) as Backup in Instrument Meteorological Conditions (IMC) When Instruments Fail

                 Garmin GPS 150

I am shocked how many pilots are unaware of the seriousness of the situation when all gyro-derived information is lost while flying in Instrument Meteorological Conditions  (IMC). If you are unable to determine whether your aircraft is turning, you will shortly end up in a fatal spiral. It doesn’t matter one whit whether you are a brand new instrument pilot or whether you have 3,000 or 4,000 hours of instrument time under your belt. You will be dead shortly.

I have had many opportunities to demonstrate this to numerous student pilots as well as to my high-time pilot friends. My demonstration begins by failing all the gyros including the turn coordinator (or turn-and-bank) while in trimmed level flight, with the pilot under the hood. 

In every case, the flight appears to continue normally for a short period of time. Inevitably one wing or the other will drop and a small turn will develop. Having no turn information, no corrective action is taken. As the turn develops, the nose begins to drop and the airspeed begins to increase. The pilot will usually recognize those cues that something is happening and will increase the back pressure on the yoke in an effort to stop the increase in speed and loss of altitude.
Cessna Skymaster
Cessna 337 Skymaster

This is the beginning of the end. As he pulls back on the yoke, this causes the bank angle to increase. When the bank angle increases the airspeed accelerates even faster. By now altitude is being lost at a greater and greater rate and he begins to pull back on the yoke with an ever increasing force. 

This can generate enough load to fail some portion of the aircraft structure resulting in loss of control of the aircraft and certain death.

In order to maintain control of our aircraft while in Instrument Meteorological Conditions  (IMC) conditions, it is absolutely necessary to have turn information. We normally obtain this information from the directional gyro with supporting information from the attitude indicator and turn coordinator instruments. But what if they fail?
Lets see if there is another source of information in our cockpits that can provide turn information. There are in fact, several in most of today’s aircraft.

Global Positioning System (GPS) as a heading indicator

Like many of you, I was an early adopter of Global Positioning System (GPS) navigation for aircraft. And it did not take me long to see the value of using the turn information created by these systems as a substitute for turn information generated by gyros.

In fact, I just returned from a flight in my Cessna 182P that validated the theory. I had a flight instructor as a safety pilot. While flying solely by reference to instruments, the attitude indicator, heading indicator, turn coordinator and magnetic compass were all covered. My sole source of turn information was the left/right "needle" of the Course Deviation Indicator (CDI) built into my Garmin GPS-150. And this proved sufficient information—along with the altimeter, airspeed and vertical speed indicators—to prevent the aircraft from entering deadly spiral.

In fact, I had the instructor simulate moderate turbulence with inputs from his yoke and was able to maintain straight and level flight. Like most GPS receivers, my Garmin GPS-150 is equipped with the ability to update information at the rate of once per second. This rapid update ability gave me the sensitivity needed to prevent the spiral developing. 

In fact, I believe that any GPS receiver could serve in this capacity, even the portable hand held units as long as it had the rapid update capability. Even a LORAN would probably work, although not as well because it’s update rate is slower.

Recently, I purchased a Garmin GPSMAP-195 handheld. This magnificent device combines an extraordinary 12-channel GPS receiver with a remarkable high-resolution graphic display. And one of the "pages" that the device can display is an electronic Horizontal Situation Indicator (HSI) display which mimics the functionality of a panel-mounted HSI with uncanny precision…right down to its settable heading bug! 

In the event of a pitot tube or airspeed indicator failure, the GPS groundspeed could be used as a rough speed reference. And if the static system or altimeter failed, the GPS altitude readout can provide an adequate altitude reference, give or take a couple of hundred feet.

Clearly, a modern GPS receiver is useful for more than its intended navigation purpose and could serve a pilot well in the event almost any conceivable flight instrument failure. And now that GPS is found in almost every aircraft, pilots should be trained in using the GPS for this purpose.

Interestingly enough, there has been some experimental work done recently with GPS-based attitude indicators. If you mount a GPS antenna on each wingtip and program a GPS receiver to monitor both antennas and compare the "GPS altitude" of the two wingtips, the GPS can display roll attitude quite accurately. It turns out that Selective Availability and other GPS errors cancel out, since you're only interested in the difference between the altitudes of the two wingtips, not the actual altitudes! 

So it's entirely within the realm of possibility that GPS may replace all gyros in our panels of the future...or that gyros may be considered backups for the GPS (instead of the other way around).

The "whiskey compass" as a backup

The magnetic compass is another source of turn information that is little used. The reason is that most pilots promptly forgot everything they learned about magnetic compass turning and acceleration errors about five minutes after they passed their instrument checkride.

The most important thing to remember about the magnetic compass turning errors is what the compass does when you’re on a southerly heading in the northern hemisphere: the compass leads any turn by approximately your latitude. (I.e., if your present location is 30 degrees north latitude, the compass will lead your turns by approximately 30 degrees.) 

The amount the compass leads your turn is not nearly so important as the fact that it is indicating a turn in the correct direction.
In other words, the magnetic compass can and does provide correct turn information while on a southerly heading. If you can manage to turn your aircraft to a southerly heading before all your gyro-derived information is lost, you should be able to prevent the development of the deadly spiral by reference to the magnetic compass.

Whenever I demonstrate the ability to maintain control under the hood solely by using the magnetic compass, I usually end up flying a series of shallow banked turns to the left and to the right, but in general maintaining a southerly heading. These are the result of using the compass to indicate when it is necessary for me to input aileron control to stop any turn that develops. 

When the compass stops indicating a turn, I neutralize my aileron input. However, I have usually input more control than necessary to stop the turn and end up making a turn in the opposite direction.

Boeing B-17

I must give credit for my source of information about using the magnetic compass as a turn information source to a World War II B-17 pilot whose name I have forgotten. He was a featured speaker at some long-ago luncheon and related how this technique got more than one battle damaged aircraft to safely descend through IMC conditions to Visual Flight Rules (VFR) conditions where they could then safely navigate to their home bases.

To complete this discussion of the magnetic compass, you will recall the magnetic compass will lag any turn while on a northerly heading. In fact it will not indicate any turn at all while on a northerly heading until a heading change of approximately of 30 degrees has occurred if the turn is a very small bank angle.

The magnetic compass will, while on an easterly or westerly heading, incorrectly indicate a turn due to acceleration or deceleration. If you are on a westerly or easterly heading, acceleration will indicate a turn towards the north. Conversely, if you are on an easterly or westerly heading, deceleration will cause the magnetic compass to indicate a turn towards the south.

It is important to note that there is no acceleration or deceleration turning error while flying either a northerly or southerly heading. While flying a southerly heading (in the Northern Hemisphere) the magnetic compass will actually lead any turn and indicate the turn is occurring in the proper direction. In fact, you might consider the compass as extremely bank-angle-sensitive in the proper direction while on a southerly heading.
Automatic Direction Finder (ADF) By King Radios

To complete this discussion of alternative turn information sources found in today’s cockpits, I would point out the Automatic Direction Finder (ADF) found in many aircraft is an excellent source of heading information in the event of loss of all gyros. Simply tune the radio to some facility more-or-less ahead of the aircraft and use the needle to provide your needed turn information.
This article was published by Avweb in 1998 and can be viewed at:

Monday, January 16, 2012

Flight Under Visual Flight Rules (VFR) in Class A Airspace? Is it legal?

Airspace Classifications

     Every pilot is taught flight operations in Class A airspace must be conducted under Instrument Flight Rules (IFR.) No exceptions. Right? Wrong! There are circumstances under which Visual Flight Rules (VFR) operations in Class A airspace are not only appropriate but required.

     I'll bet most of you who have read the title of this article are already saying to yourself, "Visual Flight Rules (VFR) flight in Class A airspace is not permitted and you must have an Instrument Flight Rules (IFR) clearance to operate at or above FL180. This author must be crazy to try to write an article about a  procedure that is definitely not permitted!"

This reaction is typical of pilots to whom I have presented the question outlined in the title. The correct answer to the question, however, is yes! There is a set of conditions when not only is it legal  but you have no choice in the matter and you must conduct your flight under Visual Flight Rules (VFR) while in Class A airspace.

     The set of conditions I am referring to applies in a situation where you lose all two-way radio communications while operating on an IFR clearance in Airspace A.

     The reason for writing this article is that I believe I have discovered a gap in pilot knowledge. This gap reveals that most pilots are not aware it is possible to fly under VFR while operating in Class A airspace. The crew's experience level — whether a 20,000-hour airline captain or co-pilot, a military crew or a freshly minted instrument-rated private pilot — does not matter, nor does it matter if the aircraft is a C-5A transport, a F-15 Eagle or a Cessna Citation.

     I first became aware of this gap approximately 30 years ago. At that time, I was the head of a company in the business of providing ground instruction for pilots and writing a course outline for my instructors to teach. The ground instruction was directed toward those pilots who desired to obtain an Instrument Rating or Air Transport Pilot certificate. While researching the loss of communications, I discovered the provision for VFR flight in what is now defined as Class A airspace.

    The Scenario:
Level at FL350 Just East of PIT
    Let us imagine you are the captain of a Boeing 747-100 headed to Los Angeles (LAX) and have just leveled off at your cruise altitude of FL350 after taking off from  John F. Kennedy airport (JFK.) In this case, I will put a little more pressure on you and include the situation that there is a very knowledgeable additional crew member on board your flight:  a Federal Aviation Administration (FAA) Air Carrier Inspector on a routine line check of you and your crew.

The clearance you received before departing JFK is the following:

     "TWA 841 is cleared to the Los Angeles Airport via the Kennedy Seven Departure, with a Canarsie climb, direct to RBV J230 AIR J80 MKC J24 SLN ALS J44 FMN J64 CIVET, maintain FL350, squawk 6221"

     The takeoff and departure are routine and you level off at FL350, approximately 50 miles west of Harrisburg on J80. The weather is "severe clear" and from your altitude, Greater Pittsburgh International Airport (PIT) will, very shortly, be in view. Now comes the fun for you and your crew as you discover that you have lost all communication capability.

     No member of your crew or passengers has brought along a handheld VHF transceiver or cellphone. You are truly without communication capability. The proper setting of the transponder to code 7600 is one of the first items to be handled. What is the next proper course of action? (Remember, one of the FAA's finest is seated right behind you in the jump seat.) When I ask this question, most pilots will initially say that they are going to continue on to LAX via the routing and assigned altitude in the clearance that was last received.

The Regs
I take the position with the pilot that this is not the correct course of action. I then remind him that a violation of the FARs filed by the Air Carrier Inspector will most likely result in spending a month on the beach without pay. At that point, most pilots will take out their Jeppesen Manuals to do a little "open book" research and will correctly turn to the page containing FAR 91.185 which says, in part:

91.185 IFR operations: Two-way radio communications failure.
(a) General. Unless otherwise authorized by ATC, each pilot who has two-way radio communications failure when operating under IFR shall comply with the rules of this section.
     (b) VFR conditions.  If the failure occurs in VFR conditions, or if VFR conditions are encountered after the failure, each pilot shall continue the flight under VFR and land as soon as practicable. (emphasis added)

     Usually, the pilot will gloss over or not even read paragraph (b) which is the controlling part of the FAR. Note that it contains the word "shall," which when used in a regulation, gives the reader no option other than to comply. When directed to reread paragraph (b) very carefully, usually a look of consternation appears on the pilot's face when confronted by the word "shall."

     The Airmans Information Manual (AIM)
     The discussion then takes on a note of interest or puzzlement for the pilot because he has apparently never considered it before. It also gives me the opening to ask if we are in fact in "VFR" weather conditions. Most pilots answer, "We are in Class A airspace and no VFR operations are permitted here." This gives me the chance to direct the student to the Airmans Information Manual (AIM), which offers an expanded discussion about two-way communications failure in VFR weather conditions while in Class A airspace. The part that applies is in chapter 6 and reads as follows:
6-4-1. Two-way Radio Communications Failure...
2. VFR conditions. If the failure occurs in VFR conditions, or if VFR conditions are encountered after the failure, each pilot shall continue the flight under VFR and land as soon as practicable.

     NOTE :  This procedure also applies when two-way radio failure occurs while operating in Class A airspace. The primary objective of this provision in 14 CFR Section 91.185 is to preclude extended IFR operation by these aircraft within the ATC system. Pilots should recognize that operation under these conditions may unnecessarily as well as adversely affect other users of the airspace, since Air Traffic Control (ATC) may be required to reroute or delay other users in order to protect the failure aircraft. However, it is not intended that the requirement to "land as soon as practicable" be construed to mean "as soon as possible." Pilots retain the prerogative of exercising their best judgment and are not required to land at an unauthorized airport, at an airport unsuitable for the type of aircraft flown, or to land only minutes short of their intended destination.

     Obviously, the note in the citation above specifically states VFR flight is permitted in Class A airspace if there is a two-way radio communication failure.
     More Regs...
     Occasionally a pilot will ask, "What is the minimum in-flight visibility and cloud clearance while in Class A airspace?" This can be answered by suggesting a close look at FAR 91.155, which says:

      Sec. 91.155 Basic VFR weather minimums:
More than 1,200 feet above the surface and at or above 10,000 feet Mean Sea Level (MSL), 5 statute miles visibility, 1 mile from clouds and 1,000 feet below clouds and 1,000 feet above clouds.

     By now, many pilots are convinced that you can operate under VFR in Class A airspace. I take this opportunity to suggest that it's time to reconsider our original course of action in light of these discoveries. (As you may recall, Flight 841 was going to proceed on to LAX via the original routing and at FL350.) Most pilots will look outside the window, spot  Greater Pittsburg Airport (PIT) and announce they are going to proceed under VFR and land at PIT. I agree this is the correct course of action.

VFR and Part FAR Part 121 operations.

*Formerly Air Transport Association
     For the benefit of those who are not airline pilots, recognize that some airline pilots never get to experience VFR operations while flying the line. Many have mistakenly interpreted their company's operating procedures as well as the FARs as mandating no VFR operations while carrying passengers. This may not be true. The matter of VFR operations is the subject of an agreement among members of the *Air Transport Association (ATA). (Note:  The name change from Air Transport Association to "Airlines for America" occurred late in December 2011).The ATA for all practicable purposes comprises all major U.S.-based airlines. If the individual airline incorporates the ATAagreement into its Operating Policy Manual, VFR flight by that airline is permitted under the FARs.

This agreement essentially permits VFR flights operating within the terminal area, for good reason (such as ATC delays, excessive rerouting, etc.) to cancel their IFR flight plan or accept a VFR restriction for flights provided certain criteria are met. These criteria include VFR cloud clearance and visibility requirements and that the aircraft is receiving radar vectors by ATC. At uncontrolled airports, the pilot must be in direct communication with either tower, approach control, or departure control, etc.

More Food For Thought

     No Radio communications (NORDO) In The Terminal Area...

     We are now in agreement that proceeding to and landing at PIT under VFR is the proper course of action. But we now need to review the rarely-used procedures for landing at a major airport without an operating two-way radio. These include a discussion of the method of determining the proper runway (observe the windsock and the runway in use by existing traffic) and a review of the light signals (Airmans Information Manual chapter 4-3-13) expected to be seen in this situation (a steady green light means "cleared to land").

...And The Proper Altitude

     The landing at PIT covers the situation where a suitable airport is nearby when we experience our loss of communication. But what if the communications loss occurs when the nearest suitable airport is, for example, 600 miles west of our position? Of course, our last assigned altitude, FL350, is an IFR altitude. Since we must proceed under VFR, an altitude change is in order.

     Some pilots suggest a descent be made to permit flight beneath Class A airspace. Although this would indeed be a legal course of action, the greatly increased fuel consumption at this lower altitude would not permit us to complete the flight with safe fuel reserves. The procedures concerning loss of two-way communications takes this situation into account by permitting us to maintain a higher, more efficient cruising altitude. The correct altitude for our continuing flight would be found in FAR 91.159:

Except while holding in a holding pattern of 2 minutes or less, or while turning, each person operating an aircraft under VFR in level cruising flight more than 3,000 feet above the surface shall maintain the appropriate altitude or flight level prescribed below, unless otherwise authorized by ATC:

a) When operating below 18,000 feet MSL and—
   (1) On a magnetic course of zero degrees through 179 degrees, any odd thousand foot MSL altitude +500 feet (such as 3,500, 5,500, or 7,500); or
   (2) On a magnetic course of 180 degrees through 359 degrees, any even thousand foot MSL altitude +500 feet (such as 4,500, 6,500, or 8,500).

(b) When operating above 18,000 feet MSL to flight level 290 (inclusive) and—
   (1) On a magnetic course of zero degrees through 179 degrees, any odd flight level +500 feet (such as 195, 215, or 235); or
   (2) On a magnetic course of 180 degrees through 359 degrees, any even flight level +500 feet (such as 185, 205, or 225).

(c) When operating above flight level 290 and—
   (1) On a magnetic course of zero degrees through 179 degrees, any flight level, at 4,000-foot intervals, beginning at and including flight level 300 (such as flight level 300, 340, or 380); or
   (2) On a magnetic course of 180 degrees through 359 degrees, any flight level, at 4,000-foot intervals, beginning at and including flight level 320 (such as flight level 320, 360, or 400).

     FAR 91.159 clearly indicates a choice of a cruising altitude of FL360 would be more appropriate for our direction of flight. Possible choices would also include FL 185, FL205, FL225, FL245, FL265, FL285, FL320, FL400, FL480, FL520, FL560 and, of course, FL600 and above. Most pilots will agree that climbing to FL360 is a proper course of action.

Summing Up

    Without the benefit of the above knowledge, most pilots would continue their flights after loss of two-way radio communications all the way to their destination. This would mean they could be operating in the system for as long as five hours or more without communications capability. This would cause ATC untold hardships as well as possible altitude and routing restrictions to other flights operating in the vicinity.

     In addition, if your destination airport has no radar coverage, ATC is not permitted to authorize flight by other IFR aircraft in its airspace for a period of time of 15 minutes prior to your ETA and for as long as one hour after your ETA. If you continued on to your destination when a landing could have been made safely under VFR at an airport short of your destination, I can guarantee a greeting committee of an unfriendly nature upon your arrival.

     To sum up, if you are operating in the Class A airspace and experience loss of two-way communications, you must proceed under VFR and land as soon as it is practicable. Provisions have been incorporated into the FARs to permit this safer course of action. The AIM actually encourages operation under VFR.
      Lastly, I must add that all situations are different and it is up to the pilot-in-command to determine whether to use the pilot's emergency authority. Would you actually fly VFR in Airspace A to follow these procedures or would you chose not to? Why?

     You can find this article originally as published by Avweb in the year 2000 (five years prior to the implementation of Reduced Vertical Separation Minima (RVSM) at: