This 'n That

The past couple of weeks have been uncharacteristically busy for a flight instructor without a medical certificate, but here's a grab bag of items that some readers might find interesting.

Villa of the Basking Hounds



It's been four months since Rio and Taz came to live with us and there's lots of progress to report. At first, Taz was distant and enigmatic while Rio was fearful, underweight and, frankly, more than a bit neurotic. With patience, a regular exercise routine, obedience training, and some TLC these two have begun to blossom. Taz has revealed her playful and mischievous side. Rio, while still a bit thin, has slowly begun to put on weight. He's also become much calmer and no longer shakes at the slightest sound. In fact, he barely reacted to last night's fireworks.

Part of their transformation is due, in part, to regular romps at Point Isabel Regional Shoreline. Situated on the Northeastern shore of San Francisco Bay and just a few minutes drive from our house, Point Isabel is the nation's largest off-leash dog park with 23 acres of space. Here's a photo of Rio and Taz sitting atop a picnic table with the Oakland/San Francisco Bay Bridge and the San Francisco skyline in the distance.



We've very glad to have these two basenji in our lives and it wouldn't have been possible without Basenji Rescue and Transport and their dedicated volunteers. If you ever have an urge to donate to a non-profit, BRAT would be an excellent choice.

Lights On, Nobody Home?

For many years there have been two navaids at the Oakland Airport that have not been part of any instrument approach, yet they have been maintained and continued to operate. I'm talking about the CASES outer marker and the RORAY (AK) locator middle marker. I regularly flew with pilots who, while on the ILS RWY 27R, would announce the final approach fix when they saw the blue light flash on their marker beacon receiver. I'd point out, often to their amazement, that the outer marker was no longer part of the ILS and, in fact, wasn't part of any approach into Oakland.

CASES (5 DME from the OAK VORTAC) used to be the FAF for the ILS, but that was changed several years ago. The first change was to move the FAF to 5.5 DME from the OAK VORTAC, add the requirement for DME when flying the localizer-only version of the approach, and call the new final approach fix FITKI. If memory serves me correctly, that was about five years ago. A few months later, the FAF was renamed to CUVSA. The new FAF was located at 5.5 DME, yet the CASES OM at 5 DME continued to function. A few months ago, the FAA even issued a NOTAM telling pilots that the CASES OM would be out of service. Did they not know that it wasn't being used or is it part of some procedure not known to me and which is not published on the NACO web site? Or maybe they just forgot? Beats me!

The RORAY LOM also continued to function, something I'd periodically verify whenever I flew an aircraft that had a functioning ADF (which isn't often these days). I'd dial in 341 on the ADF, watch the needle swing toward the approach end of 27R, and hear the Morse code "AK."

Not wanting to rush to a decision or do something rash, the FAA has finally decided to decommission these two navaids.

Runway Re-Numbering

Astute readers know that the earth's magnetic field is constantly and (usually) subtly shifting. This can and has affected runway numbering schemes, which are supposed to be based on the magnetic direction of the centerline, rounded up or down to the nearest 10 degrees. At Tracy, runways 7/25 recently were changed to 8/26. And runways 16/34 at Davis University just became 17/35.

Now Oakland's RWY 27L and 27R centerlines have been 276 degrees for quite a while and I often had instrument students ask why they weren't 28L and 28R. I had to confess that I didn't know. Now it appears the process to renumber those runways may have finally begun. Again, you don't want to rush into anything ...

Draggin, in a good way

The two questions I answer most often are "Have you gotten your medical certificate back?" and "When will you get your medical certificate back?" I've toyed with the idea of having a button made that simply says "October." That way I could wear the button and when asked either of these questions, I could just point to button. I'm trying to not be impatient and mostly have taken my respite from PIC duties in stride, but I will be glad when this is resolved. It is a reminder to all pilots out there, young and old, to relish all of your flights because we are all just a medical exam away from losing our privileges.

So I decided that resuming the Citbria check-out I started over a year ago might be just what was needed to lift my spirits.



All of my previous tailwheel time was in a 152 Aerobat Texas-Taildragger conversion and I was fortunate to have Ben Freelove as my inital tailwheel instructor. Ben liked to refer to the 152 Texas-Taildragger as the "Scare-o-bat" because of it's occasionally hair-raising takeoff and landing characteristics. By comparison, the Citbria is well-mannered and stable with plenty of rudder and aileron authority.

My instructor for the recent Citbria flights was Jeff Reeder, a seasoned banner-tow pilot who's flown a variety of tailwheel aircraft. Jeff put me through the paces, which culminated in the trifecta: Multiple successive landings on Oakland's 27L - the first a wheel landing on the left side of the centerline, the second a wheel landing on the right side of the centerline, and a three-point landing to a full stop with 2000' of pavement still remaining.

Mountain High

Lastly, here are some photos from a recent mountain check-out flight I did for a former student to Reno-Stead. The winds aloft were fairly calm and we only saw some light turbulence over the Sierra Nevada.





Later this week I'll post a review of ReadyProcs, a slick application for downloading and viewing terminal procedure charts. Until then, here's wishing you a pleasant summer and safe flying.

Flying in the (Alphabet) Soup

NOTE: For a more up-to-date discussion, see Understanding RNAV Approaches.

NDBs are being phased out, GPS manufacturers are claiming that soon everyone will fly precision approaches to airports with virtually no specialized equipment on the ground, GPS approaches with vertical guidance are being created at an impressive rate, Garmin has finally certified the long-anticipated WAAS upgrade for their popular 430/530 GPS receivers, and the FAA says in the Instrument Rating Practical Test Standards that a GPS approach with vertical guidance is still considered a non-precision approach.

Yes, the aviation world has gone crazy.

If you need more evidence, look at this approach chart and you'll see three different approach minima: LPV, LNAV/VNAV, and LNAV. To understand which minima apply to the aircraft you are flying, you'll have to jump into the alphabet soup. First, here's my take on the history of RNAV which I think is relatively accurate.

Back in the late 1970's and early 80's, RNAV units (think "aRea NAVigation) like this King KNS-80 were the coolest thing since sliced bread because they allowed a pilot to create waypoints (colorfully referred to at the time as "phantom stations") based on DME distances (called Rho) and VOR radials (called Theta). And no one seemed to mind much that using these units often required a lot of button pushing and knob twisting. And as reliable and affordable Rho-theta navigational systems became available, the FAA began developing approach procedures for these units called RNAV approaches.

In large, expensive aircraft, multi-sensor Flight Management Systems (FMS) became widespread. These FMS utilized a variety of ground-based navigation aids, combined with inertial reference units, to provide seamless and accurate navigation.

When IFR-certified GPS units came along and the FAA began creating GPS approaches, they were worried about reliability. So they created GPS approaches that overlaid existing VOR or NDB approaches and required the pilot to have the other navigational equipment on board and to monitor that equipment during a GPS approach. Gradually the FAA became convinced that GPS was maybe pretty good, they no longer required the pilot to monitor the other navigation systems, and they even created (gasp!) stand-alone GPS approaches where GPS was the primary means of navigation.

I won't even go into LORAN, a land-based radio navigation system that seemed to fall out of favor for air navigation quicker than you can say "decommissioned NDB." And as FMS and IFR-certified GPS units became widespread, the FAA decided that it needed a broader category that would contain Rho-theta systems, FMS, and GPS. Rather than come up with a new term, the existing term RNAV was redefined to include them all.

To accommodate both FMS and GPS-equipped aircraft, approaches started being created with titles like RNAV (GPS) RWY 31. In some cases, there was more than one version of an RNAV (GPS) approach to the same runway and the title had to have a suffix added like Z or Y added to the end to get around the limitation in many FMS databases that precluded more than one approach having the same name.

ICAO standards began to be formed for Required Navigational Performance (RNP) to describe the accuracy required of air navigational systems for different phases of flight. Recently, RNP approaches have been created for specially authorized aircraft and flight crews that combine curved approach and departure paths with reduced obstruction clearance that some might call spine-tingling. And in classic, confusing fashion, the term RNP, initially developed to describe the accuracy of navigational systems, was appropriated as an approach classification, too.

The nice thing about standards is that there are so many of them.

So where are we today? RNAV includes any IFR-certified GPS, multi-sensor FMS (many include GPS in the array of navigational sensors), or approved Rho/Theta unit (like the now ancient KNS-80). I won't go into which equipment suffix you add to your aircraft because that depends or whether or not your aircraft meets the new Reduced Vertical Separation Minima standards. We now have RNP approaches (requiring special aircraft and aircrew training and certification), RNAV (GPS) approaches that can be flown with an IFR-certified GPS or the appropriate FMS, standalone GPS approaches, GPS overlay approaches (with titles like VOR or GPS A), and all the standard VOR, ILS, LOC and NDB approaches. Eventually, all standalone GPS approaches with names like GPS RWY XX will be renamed RNAV (GPS) RWY XX. So now that it's established, at least for now, what RNAV means, take a look at the different minima on RNAV (GPS) approaches.

For aircraft with older IFR GPS units certificated under TSO C129A1 (not WAAS-enabled), you're stuck with LNAV - lateral navigation - minima. This means you'll fly a non-precision approach with a Minimum Descent Altitude (MDA) and a visibility restriction. In the U.S., visibility ultimately determines whether or not you can legally descend below the MDA and land. If you have a GPS certificated under TSO C145A or C146A (WAAS-enabled), you can use the LNAV, LNAV/VNAV, or the LPV minima. In case you're wondering, LPV (according to the Aeronautical Information Manual's glossary of terms) stands for "Localizer Precision with Vertical guidance." There is also the acronym APV - which seems to be a broader category - Approach with Vertical Guidance. Interestingly, the FAA's Instrument Procedures Handbook says that LPV is not an acronym - our tax dollars at work! Anyway, the topic at hand is knowing which set of minima to use.



Since I have yet to fly an aircraft with a GPS unit certified under TSO C145A or C146A (aka WAAS-enabled), I have been reading the new manual for the Garmin 530W (WAAS-enabled) and it contains some enlightening details. Using the 530W, you load the KSLE RNAV (GPS) approach just as you would any other GPS approach, specifying the Initial Approach Fix you wish to use to transition to the approach or the Vectors-to-Final option if ATC is guiding you to the intermediate approach course.



Two miles from the Final Approach Fix (LOTKE), the CDI sensitivity will begin to change from TERMINAL mode (full scale CDI deflection representing 1.0 nautical miles) to an angular course width of 2˚ or the width specified for the approach. Sixty seconds from LOTKE, the receiver will check the Horizontal Arm Limit (HAL) and Vertical Arm Limit (VAL) to determine if there is sufficient GPS course integrity to perform the LPV approach. If there is sufficient integrity, you'll see the TERM annunciation in the lower left of the 530's display change to LPV and that, along with a glide slope indication on your CDI or HSI, is your cue to use LPV minima. You should intercept the LPV glideslope just as you would an ILS glideslope and descend to the Decision Height shown on the chart before landing or executing the missed approach procedure.



If there isn't enough course integrity to provide an LPV approach (did you check GPS NOTAMs prior to takeoff?), the annunciation will change to LNAV and you'll see a message "Approach downgraded - use the LNAV minima." The Garmin manual refers to an LPV approach as a "precision approach" in spite of the fact the FAA currently still considers an LPV approach to be a non-precision approach. And if the course integrity isn't sufficient for an LNAV approach, you'll see a message telling you to abort the approach, the annunciation will change to TERM sensitivity, and you should climb, fly to the Missed Approach Point, and then execute the missed approach procedure.

Since you might not know which set of approach minima will apply to your approach, how do you request the approach? The FAA's Instrument Procedures Handbook says that if the approach has a title like "OAK RNAV (GPS) RWY 27R", you should tell ATC "request the Oakland RNAV 27 Right approach." Yet when I've done this, the NORCAL controllers seem a bit confused and ultimately clear me for the "Oakland GPS 27 Right approach." The bottom line is that as far as ATC is concerned, you are flying an RNAV approach. It's up to you to fly the appropriate minima.

While it strikes me as an odd design choice to have a GPS receiver that doesn't know which type of approach you will be flying until 60 seconds before the final approach fix, I like the fact that this emphasizes something many pilots fail to grasp: GPS is not infallible. An unwelcome increase in workload for GA single-pilot IFR comes from having to brief more than one set of approach minima, depending on the GPS receiver's performance. Crossing the FAF is not the right time to throw the pilot a curve, but there's more, unfortunately. Here's a quote from the Garmin GNS530W Pilot Guide and Reference:

GPS approaches with vertical guidance may be either LNAV/VNAV or LNAV approaches with advisory vertical guidance. LNAV-only approaches with advisory guidance only have LNAV minima listed on the bottom of the approach plate. The glidepath is typically denoted by a light dashed line on the vertical profile (Jeppesen only) with an associated glidepath angle (usually in the 3.00˚ range). These approaches are indicated with "LNAV/+V".

For approaches with LNAV/VNAV minimums, those will be controlling. For LNAV approaches with advisory vertical guidance, the LNAV minimums will be controlling. Approaches confirmed as "LNAV/VNAV" approaches in the Jeppesen NavData are indicated with an "L/VNAV" annunciation. At the time of this publication, not all of the LNAV/VNAV approaches have been identified as such in the Jeppesen NavData, therefore some LNAV/VNAV approaches may still be identified with "LNAV/+V" annunciation.

Riiiight!

You can download newer versions of the Garmin 430 and 530 PC simulators that have updated databases (spring of 2006), but they don't appear to let you experiment with any of the LPV or LNAV/VNAV behavior. Oh, and on my PC the simulator constantly displays a message that the GPS processor needs servicing.

If you've waded through all this mess, let me offer my last observations. Designing instrument approach and departure procedures has become increasingly complicated. While new technology promises to make instrument flying safer, it's not clear to me that this is actually happening. A pilot's job in the cockpit has become a morass of details and minutiae. Many of the systems pilots are being forced to use seem to have been designed by people who like puzzles and who are probably not pilots themselves. So if you are an instrument-rated GA pilot who flies single-pilot IFR, your work could end up being more complicated than ever. The more things change, the more they stay the same, I guess.