Monday, March 30, 2009

'Chute First ...

I've read with great interest some assertions about Cirrus aircraft, the pilots who fly them, and whether or not the airframe parachute makes the Cirrus pilot safer or just emboldens them to take risks. By now most of you know that on Sunday, March 15, 2009, a 64-year old instrument-rated private pilot flying a new Cirrus SR22 elected to deploy his aircraft's airframe parachute shortly after takeoff from Montgomery County Airport in Gaithersburg, Maryland. He departed runway 34 and his plane came to the ground about a half mile from the airport, no injuries were reported on the ground, the pilot walked away, and the aircraft was substantially damaged. It's dangerous to generalize, but I feel compelled to make some observations about this particular accident, the pilot's decision to launch into the weather, the efficacy of Cirrus door latches, and under what conditions a Cirrus pilot should consider deploying the 'chute.

The pilot involved in this particular accident was reported to have had 320 hours total time and I'm assuming, given his age, that he came to flying later in life. None of the reports I've read give any specific numbers, but given his total time and the fact that his last certificate was issued in June of 2007, it seems reasonable to assume that he didn't have much experience with solo flying in IMC. A low time pilot with a powerful and capable aircraft can be a dangerous, sometimes even deadly combination, and this accident would seem to reinforce that belief. And let's be clear that while this accident happened to involve a Cirrus, most any brand of high-performance aircraft will do.

An important part of instrument training involves making a competent go/no-go decision. Heck, it's explicitly called out in the Instrument Rating PTS as something the candidate must demonstrate. I sat on the ground a few years back with a Cirrus owner while we waited for the weather to clear. The radiation fog was thick and the surface winds were gradually starting to increase and mix out the fog, which made waiting all the more uncomfortable. But wait we did because, parachute or not, the conditions did not meet my minima for departure.

Turn in your hymnals to 14 CFR 91.175 and you'll find specific departure weather restrictions for aircraft operating under 14 CFR 135 and 121. Taking off under conditions with zero visibility and zero ceiling is not expressly forbidden when operating under part 91, but that doesn't mean it's a good idea nor does it mean that if you do so and you run into problems that you won't be scrutinized for violating 14 CFR 91.11 (Careless or reckless operation) - endangering the life or property of another. In our Me First society, it is easy to forget that our actions may indeed have adverse effects on others. This is where an instrument instructor's job of teaching risk management begins.

The accident pilot elected to launch with a reported ceiling of 400 feet and 2 miles visibility. Shown above are the takeoff minima published for Gaithersburg, which don't specify any ceiling or visibility. That means the 14 CFR 91.175 standards of 1 mile visibility for aircraft with two engines or less apply to part 135 and 121 operators. Technically the accident pilot was not prohibited from departing since he was operating under part 91.

The absolute lowest personal departure minima for a single-engine aircraft that I recommend to pilots I train for the instrument rating are pretty simple: The surface weather observation must be equal to or better than the highest circling minima (ceiling and visibility) for the airport, just in case an emergency return is required. In a twin-engine aircraft, I'm still pretty conservative and recommend the conditions be no lower than the highest straight-in minima of all non-precision approaches available at the departure airport.

When I flew freight in the Caravan, my company's procedures allowed us to depart in some really crummy conditions. On several occasions, I departed when the greater Bay Area was blanketed fog and with low IFR conditions at all nearby major airports. And you know what? It gave me the creeps every time I did it.

I've never flown into Gaithersburg, but a quick review of the available approaches show the following circling minima.

GAI NDB RWY 14 - 1 SM vis & 1380 feet MSL, 841 feet Height Above Threshold
GAI VOR RWY 14 - 1 SM & 1200 feet MSL, 677 feet HAT
GAI RNAV (GPS) RWY 14 - 1.5 SM & 1020 feet MSL, 481 feet HAT

In case you're wondering what I'm getting at, the low-time instrument-rated accident pilot took a pretty big risk when he chose to depart with 2 miles visibility and an overcast ceiling of 400 feet at an unfamiliar airport.

I've written before about my experiences with the door latches on a Cirrus SR22 that I used to fly. Quite frankly, I found the performances of these door latches stinks. Cirrus, in an apparent quest to make the aircraft seem as much like an automobile as possible, tried to implement a slam-and-shut-style automobile door. This just in: A high-performance single-engine aircraft is not a car. My experience showed me that the latches on an SR22 G2 must kept adjusted just right by a mechanic and the pilot had best ensure the doors are secured, top and bottom, before taking off. Interesting, the door latches on an older SR20 that I used to fly had a very positive door mechanism with a latching handle.

So a door popping open on a Cirrus is not uncommon and the AFM even has a procedure for handling it - abort the takeoff if you can, otherwise reduce your speed and land as soon as practical. A door popping open can be distracting as hell, especially to a low-time pilot, but the slipstream will keep the door mostly shut. You just need to reduce the airspeed and return to land. Of course, returning to land is going to be a lot easier if you at least have circling minima.

When I flew the Cirrus regularly, I followed all the recommended Cirrus Airframe Parachute System (CAPS) procedures. This included removing the safety pin from the activation handle before takeoff and installing the safety pin after landing. If you don't remove the pin, you simply can't be ready to deploy the parachute quickly in an emergency. I've read of several fatal accidents involving Cirrus where NTSB investigators, combing through the wreckage, found the CAPS safety pin firmly in place on the deployment handle.

Even though I followed the CAPS procedures and I regularly reviewed the deployment procedures, my mindset when flying the SR22 was that CAPS deployment was going to be an absolute last resort. The AFM gives some suggested situations where CAPS deployment is warranted:
  • Mid-air Collision
  • Structural Failure
  • Loss of Control
  • Landing in Inhospitable Terrain
  • Pilot Incapacitation
After the door opened, the accident pilot reported that his intention was to turn back and land at Gaithersburg. The accident pilot says the plane entered an unusual attitude and he let the airspeed get low, the aircraft stalled and started to enter a spin. The accident pilot said he had pressed the magic button (the autopilot Level button) to get the plane stabilized, but decided he couldn't wait for the magic button to do its magic. He was also concerned about entering restricted airspace nearby and was unfamiliar with the Gaithersburg airport environment. So he pulled the 'chute.

I'm glad he's okay and that no one on the ground was hurt, but this all seems so preventable. Low time pilots in high-performance aircraft with airframe parachute systems can learn a lot from this accident. "'Chute first" is a potentially dangerous and definitely expensive procedure. The hard questions need to be asked and answered on the ground, before the clouds are approaching, the door has opened, or the engine has quit and you feel the urge to pull that T-shaped handle.

Tuesday, March 24, 2009

New Advanced Avionics Handbook

For many years it seemed that the FAA's handbooks on aircraft flying, aeronautical knowledge, instrument flying, and weather were hopelessly outdated. Yet in the last two years there have been several updates to these publications that included new graphics and information on the latest equipment, theory, and sources of weather data. All of these books are available in PDF format at no charge, which helps reduce the cost of learning to fly or earning an instrument rating.

One of the books that caught my eye when it first came out was the FAA's Instrument Procedures Handbook. This completely new publication provided much needed information on ATC procedures, instrument approaches, and other stuff that was missing or inappropriate for inclusion in the Instrument Flying Handbook.

The latest new release from the FAA is the Advanced Avionics Handbook, which provides a lot of good conceptual information on the use of GPS and RNAV. This book does not depend on any particular brand of GPS or glass cockpit, which makes it great introduction to pilots who are considering or curious about glass cockpit or GPS training. This book touches on GPS and RNAV procedures, pitfalls, and recommended practices in a way that is independent of the model of GPS, PFD, or MFD that you might use.

While this book is not a substitute for thorough training in the use of your particular brand of avionics, it's a great way to get a leg up on transitioning to a glass cockpit or to a GPS-equipped aircraft. Even if you are experienced in using advanced avionics you should find this book contains good advice and explanations on pitfalls and common errors.

And did I mention you can download it for free? I think I did ...

Sunday, March 22, 2009

Hold Everything, Part III

For being so simple, holding patterns are a surprisingly deep topic. In this installment I'll cover some subtle points like orientation on the outbound leg, when to start timing, the 5 Ts, Dealer's Choice Entry, wind correction, station side holds, and the so-called Crisis Entry.

You Gotta Believe
When a photojournalist is mired in a crowd of people and is unable to see the subject they are trying to photograph, they often hold their camera up, point it in the generally correct direction, and click the shutter in hopes of getting a usable shot. This used to be called a Hail Mary, a term also applied to a quarterback throwing a football a great distance downfield in hopes that his receiver will be there to catch it.

An aviation equivalent of a Hail Mary is something that many new instrument pilots have a hard time grasping: Without a GPS depiction of a holding pattern you really have no positive course guidance on the outbound leg. On the inbound leg, the CDI or HSI will be centered and the ADF needle should basically be pointing straight up (aside from any wind correction angle).

If you're navigating with a VOR or ADF, you cross the fix, turn outbound, fly for a minute and see what happens when you turn inbound. If you have an idea of the winds aloft prior to entering the hold, that knowledge can certainly inform your choice of heading; more on that later.

With a GPS depiction of the holding pattern, you'll have an excellent idea of where the desired outbound leg is. Some GPS receivers capable of depicting holding patterns will even change the shape of the holding pattern race track to account for your aircraft's speed and for wind correction.

Here's the G1000's predicted holding pattern shape at 145 knots with winds out of the NNE at 25 knots.

Here's the same predicted holding pattern shape after slowing to 105 knots.

Without GPS, the first time around the hold is often a bit of a gimme - You get a better idea of the winds aloft and refine the hold with each lap you fly. This can be a good thing if you have to hold for a long time because it gives you something to do and relieves the boredom.

Five is Enough
A popular checklist mnemonic used as you cross a holding fix (or any other fix, for that matter) is the Five Ts. Some instructors teach a slightly different order and some even teach more than Five Ts. Here's my version:
  • Turn - to the outbound heading
  • Time - start your time, if necessary
  • Twist - twist the course pointer or OBS to the INBOUND course, if necessary
  • Throttle - reduce to holding speed if you haven't already done so
  • Talk - report entering the hold
Some folks insist that you start timing before you start turning, but it doesn't really matter as long as you are consistent in which you choose to do first. I teach turn before time because it works well when flying one of those rare instrument approaches that have a course change over the final approach fix.

I've seen pilots and instructors who insist on twisting the OBS or course pointer when turning outbound as well as when turning inbound in the hold. That seems a bit kooky in light of the above discussion of course guidance on the outbound leg, but I guess it's harmless as long as you keep your situational awareness.

I rarely see pilots report entering the hold, even though it's one of the compulsory reports under IFR. The format goes something like this:
Barnburner 123, entered the hold, Sacramento, 2132 Zulu.

Get Your Fix
An often misunderstood concept is when to start timing the outbound leg of the hold. When you are entering a hold using a teardrop or parallel entry, start the outbound timing when you cross the fix. When flying a direct entry or once established in the hold, start timing abeam the holding fix provided you can determine that position.

Station passage over a VOR occurs on a teardrop or parallel entry as soon as your VOR receiver shows a positive reversal of the To/From flag. For a hold over an NDB, your ADF needle will start to point behind your wing when you've passed the station. If you are holding over a VOR intersection or a DME fix on a VOR radial, the equivalent of station passage is when you have passed the cross-radial or DME distance that defines the holding fix.

If you are navigating using GPS, you need to suspend waypoint sequencing (by pressing the OBS button) unless you are holding over a missed approach holding waypoint defined in an instrument approach procedure. The nice thing here is that when waypoint sequencing is disabled and you cross the fix, the To/From flag will reverse just like when crossing a VOR station.

If you did a direct entry or are already established in the holding pattern, start timing the outbound leg when abeam the holding fix. Holding over an NDB, abeam the station occurs when the ADF needle is basically pointing off the wing. Holding over a VOR and assuming you set the proper inbound course on your OBS or HSI, abeam the station occurs when the To/From flag flips to TO.

Holding over a GPS waypoint with waypoint sequencing disabled and the proper inbound course set, abeam the station occurs when the To/From flag flips to TO.

When holding over the intersection of two VOR radials, you won't have a good indication of the position abeam the fix unless you are lucky enough to have a cross-radial is perpendicular to the inbound course. In these cases, start timing as you cross the fix and turn outbound, and after a minute you should have completed your 180 degree turn and you can start timing the outbound leg.

Holding over a DME fix on a radial without DME leg lengths, start timing when the DME distance is the same distance as that which defines the holding fix.

Dealer's Choice
When you are approaching the holding fix and your heading is within ±10˚ of the outbound course, it's really up to you as to whether you do a teardrop entry or a parallel entry. One advantage of doing a parallel entry is when winds aloft are strong. With a strong wind perpendicular to the inbound and outbound courses, tracking outbound on the inbound course provides you with positive course guidance. This means you can determine a wind correction angle for the outbound leg and apply that knowledge to flying the inbound leg.

Here's the missed approach holding for the Stockton ILS RWY 29R. Note that the G1000 is defaulting to a teardrop entry and it's probably best to follow that advice. Without GPS and using just plain old VORs, you could do a parallel or teardrop - your choice.

Wind Correction
When there's a strong wind perpendicular to the inbound and outbound legs, your holding pattern will end up looking egg-shaped rather than the idealized, symmetrical racetrack pattern. In some cases the wind will increase your groundspeed on the outbound leg and decrease your groundspeed on the inbound leg. Unless your holding instructions specified DME leg lengths, you'll need to apply a little trial and error to adjust your outbound timing so that your inbound leg takes a minute.

One rule of thumb is that whatever wind correction angle you needed on the inbound leg should be doubled or tripled in the opposite direction for the outbound leg.

Near Perpendicular Entry
You may find cases where a direct entry has you flying course almost perpendicular to the outbound course.

If you cross the fix and turn outbound, your outbound course will be so close to the inbound course that you're guaranteed to overshoot the turn to the inbound course. In these cases it can be beneficial to cross the fix and wait 10 or 15 seconds before turning outbound to but some distance between your outbound course and the inbound course. In fact, that is what the G1000 is programmed to do in these situations.

Station-side Holds
Remember that step for determining the outbound heading where you ask if the cardinal direction matches the radial? Most of the time they will match, but when they differ is called the station-side hold. This occurs where the holding fix is defined as a DME distance on a VOR radial and the holding pattern is located on the same side of the fix as the VOR station.

Look at this illustration and assuming North is up, it's pretty easy to see that the cardinal direction for this hold would be East, but the radial specified would be 270 degrees. This is where you determine the reciprocal of 270 is 090, write it down as your outbound heading, and turn to that heading after crossing the fix. To navigate on the inbound leg, your CDI or HSI should be set to 270.

Crisis Entry
Try as you might, you may get flummoxed, not be able to determine the entry procedure, and screw up your first trip through the hold. The best thing to do turn back to the holding fix (left or right turn, whichever is shortest), figure out the outbound heading, cross the fix and turn outbound again. You don't want this to happen on a check ride, but everyone makes mistakes from time to time. In real life, think of it as a mulligan or a do-over.

This concludes my series on holding. I hope you've found it helpful and enlightening!

Thursday, March 19, 2009

Fat Cats

Certain lobbying groups have been banging their PR drums lately, saying that politicians should stop picking on business ownership and use of corporate aircraft. In a way they are right, but they are also wrong. These same groups have been crying like stuck pigs about proposed security rules for aircraft with MGTOW over 12,500 pounds, saying these sorts of regulations just aren't needed.

I assiduously avoid "political" topics in my blog, but these two issues have me riled. Some individuals and businesses use so-called business aircraft in an intelligent way. Others are just plain stupid, they waste money for their own amusement, and they deserve to be called on the carpet to account for their behavior. And soon they might have to take off their shoes and be subjected to physical searches before they board business jets, like the unwashed masses who fly on the airlines. Not only am I not crying about this, I confess to just a wee bit of schadenfreude.

A few years ago, while my student was refueling a Cessna 172 at the self-serve pumps at Oakland, I noticed a Boeing Business Jet (a 737 in this case) taxi behind our Cessna and park in the FBO's "hot spot." The engines were shut down, the chocks installed, and the stairway wheeled into place and we witnessed ... wait for it ... one man in a suit deplane, get into a waiting limo and speed away. I don't know how much it costs per hour to operate a BBJ, but the carbon loading on that guy's carcass had to be unbelievably high. When a friend working at the FBO told me who the BBJ belonged to, I was glad I didn't have any of their stock in my retirement portfolio.

For comparison, a relative works for a company with two business aircraft in their fleet and they apply a formula to determine if using one of the corporate aircraft is cost effective. Part of that calculation involves the number of company personnel who must travel and whether or not a better deal can be had using a commercial airline and a rental car. If the trip comes on short notice, airline seats may come at a premium and the corporate aircraft may well be cheaper. Or they may need to fly to a location where regional airline service is expensive and the business aircraft might be a cheaper choice. If there is advance notice or only a couple of employees need to make the trip, they may well end up flying on a commercial carrier. When I heard about this approach, I was glad that I had some of that company's stock in my retirement portfolio.

Proposed security changes for aircraft with a maximum gross takeoff weight exceeding 12,500 pounds also has some groups up in arms. The problem is the additional cost of providing airline-style security requirements will increase costs and reduce profits for busness, charter and fractional operations. But the security geeks may indeed have valid concerns. A Cessna 172 can't do much damage if used as a weapon, but a Gulfstream or Hawker certainly could.

I don't travel on commercial airlines often, but as an independent flight instructor I've had to shoulder my own share of the national security burden. For several years now, flight instructors have been required to be border guards. Before giving instruction in an aircraft or simulator, we must determine if the training is for an initial pilot certificate or an additional rating. If the answer is yes, the prospective student must show us their passport or other proof that they are a US citizen. If they are a US citizen, we have to give them a logbook endorsement saying they have proven that they are a US citizen. If they are a foreign national, they have to register with the TSA and request permission to train. We get notification if their request is approved or denied. We have to photograph them and send the photo to the TSA. And we need to keep copies of all these records and any TSA-related endorsements we give for 5 years, even though the FAA requires all other endorsements to be kept for just 3 years.

And consider the periodic security checks that the TSA performs on flight schools. We have to prove that as instructors, we have undergone initial TSA security awareness training and annual recurrent security awareness training and that we have given ourselves the required logbook endorsements. Yes, that's right, this is the one time instructors actually give themselves an endorsement. So when I heard that people traveling on larger business jets might have to take off their shoes and undergo security screening, my reaction was "Boohoo!"

Claiming that any company's use of corporate aircraft is beyond reproach and dismissing out of hand any additional security for a larger aircraft is silly. But the worst part is the mindless repetition of these claims, a sadly successful strategy that seems to be the latest approach to swaying public opinion. It's not lying exactly, but it certainly is not telling the whole truth.

Will smaller airports feel the economic hurt as fewer corporate aircraft hours are flown? You bet. Will some corporate pilots lose their jobs as flight department staff are reduced or eliminated entirely? Will the cost of traveling on business jets increase if these security rules are implemented? Of course. This just in: We're all feeling the pain.

So forgive me if I don't shed too many tears for the downsizing or outright elimination of corporate aircraft flight departments. And if national security really is important, we all need to shoulder some of the burden. And if I could line up the lobbying groups, PR hacks and fat cats, and talk to them directly, the words first words that come to mind are
Why I otta ...

Disclaimer: No corporate officers, politicians, lobbyists or public relations professionals were harmed in the writing of this blog.

Sunday, March 15, 2009

Hold Everything, Part II

Barnburner 123, hold East of the Sacramento VORTAC on the 080 radial, 4 mile legs, left turns, maintain 5000, expect further clearance in 40 minutes.

In this hypothetical example you'll see that entering a hold involves just a few basic tasks:
  • Fly to the holding fix
  • Cross the fix
  • Turn outbound in the appropriate direction.
  • After a minute (or a minute and a half above 14,000') or the specified DME leg length, turn inbound.
  • Rinse and repeat
The heading you turn to after crossing the holding fix depends on your orientation to the outbound leg, but it is crucial that you know the outbound course. If you are flying a hold that is part of a published procedure, you can just read the outbound course right off the page. If you've been given holding instructions that are not published, start with step 1.

Step 1 - Write down the instructions and read them back
First things first. Don't worry about figuring out the entry at this point, just write the instructions down and confirm with the controller that you've got it right. It helps to know the elements of a holding instruction, the order in which those elements will be given, have a shorthand for recording those instructions, and above all, stay relaxed and ahead of the game. If the controller tells you they have holding instructions and you're not ready to copy, tell them to standby until you are ready.

Taken in order, a holding instruction should contain:
  • Cardinal direction of the OUTBOUND leg (North, NE, E, SE, S, SW, W or NW)
  • Holding fix (a VOR, NDB, intersection, or GPS waypoint)
  • Radial, course, bearing, airway, or route
  • Optional leg length in miles (if not specified, 1 minute legs, 1.5 minute legs above 14,000' MSL)
  • Optional left turns (right turns assumed if this is omitted)
  • Time to expect further clearance (usually to leave the holding pattern)

Here's how it might look after you've recorded these holding instructions.

Step 2 - Fly to the Holding Fix

If the holding fix is a VOR or an NDB, this is basic radio navigation that any proficient instrument pilot should be able to do while half asleep. Come to think of it, when I worked as a freight dog I often felt like I was half asleep!

If the holding fix is the current GPS waypoint, you best press the OBS button to suspend waypoint sequencing.

Within a few miles of the holding fix, begin slowing to your holding speed.

Step 3 Determine the Outbound Course

This step is crucial and there are a few questions you need to ask to determine the outbound course:

Does the cardinal direction (N, NE, E, SE ...) match the radial or bearing?
  • If YES, the radial or bearing is the outbound course.
  • If NO, the reciprocal of the radial or bearing is the outbound course.
A quick way to compute the reciprocal of a radial is to add 200 to the radial and subtract 20 or, subtract 200 and add 20. Most people find this to be easier than trying to add or subtract 180.

In this example the radial and the cardinal direction match so the outbound course is 080 degrees.

Step 4 Write down the Outbound Course

Don't leave this to chance! In a high workload moment, you may forget, then get flummoxed and blow the hold entry.

Step 5 Determine the Holding Pattern Entry

I've illustrated the next step using a G1000 HSI set to GPS, but the same technique applies to a course deviation indicator set to a VOR.

If the direction of turns wasn't specified, right turns are implied, so place your right thumb at the three o'clock position on the heading indicator or the HSI.

If left turns were specified, place your left thumb at the nine o'clock position on the heading indicator or the HSI.

Either way, your thumb should block out about 20 degrees above the three o'clock or nine o'clock position on the HSI (or CDI).

Imagine a horizontal-ish line from the top edge of your thumb that travels through the center of the HSI or heading indicator to the other side. Imagine a vertical line from the center of the HSI or heading indicator up to the twelve o'clock position.

Next, locate the OUTBOUND course you determined in step 3 on the HSI or heading indicator.

Direct Entry
If the OUTBOUND course is located on the HSI below the imaginary horizontal-ish line, do a direct entry .

Fly to the fix and turn in the specified direction to the OUTBOUND course. After a minute (or minute and a half above 14,000') or the specified leg length, turn in the specified direction back to intercept the inbound course.

Teardrop Entry
If the OUTBOUND course is located between the vertical line and your thumb, do a teardrop entry.

The initial outbound heading for a teardrop entry requires just a bit more math.

Start with the outbound course you determined above and think LARS: Left turns, Add 30 degrees, Right turns, Subtract 30 degrees to get your initial teardrop outbound heading and write it down. Crossing the holding fix, turn to the teardop outbound heading. After a minute (or minute and a half above 14,000') or the specified leg length, turn in the specified direction back to intercept the inbound course.

Parallel Entry
If the OUTBOUND course is located between the imaginary horizontal-ish line and the imaginary vertical line, do a parallel entry. In the example above, a parallel entry would be appropriate for entering the hold at Sacramento.

Fly to the fix, turn to the outbound course, and track outbound on the inbound course. After a minute (or minute and a half above 14,000') or the specified leg length, turn OPPOSITE the specified direction back to intercept the inbound course. You will need a pretty aggressive intercept angle (35 to 45 degrees) to intercept the inbound course before reaching the holding fix. After crossing the holding fix, all turns will be in the direction specified in the holding instruction.

Looks like there are a few more details to cover, so stay tuned for part III.

Tuesday, March 10, 2009

Hold Everything

Piper 123, I have some good news and some bad news. Which would you like first?

We'll take the good news first.

Piper 123, when able, proceed direct Scaggs Island. The bad news is climb and maintain 6000, hold Northwest of Scaggs on the 347 radial, left turns, expect further clearance in 50 minutes.

Direct Scaggs, hold Northwest, 347 radial, left turns, 6000, further clearance in 50 minutes.

And Piper 123, I'm working with Norcal to get you in as soon as possible and I'll keep you advised.

Okay, we just need to be on the ground before midnight or the plane will be out of annual.

This exchange occurred on a night training flight a few years ago with an instrument rating candidate. We'd gone to a Sacramento area airport, he'd flown an nice ILS approach in a steady rain, executed the missed approach and then asked for our IFR clearance back to Oakland. The surface winds at Oakland had been out of the West when we departed and were not forecast to change, but change they did. Oh, and this was on a Sunday at the end of the Thanksgiving holiday and there was plenty of conflicting airliner traffic headed into Oakland and SFO.

Holding patterns themselves are not difficult to fly, but visualizing the holding pattern and determining how to enter the hold can be vexing in single pilot operations when your workload is high. Once GA pilots pass their instrument check ride, they may not be called upon to regularly demonstrate a holding pattern and it's all too easy to lose proficiency with something you don't use often. There are a bunch of details on holding procedures that often are glossed over, so I'll cover this topic in two separate posts.

A hold can specified in a Standard Instrument Departure (SID) to allow you to climb to a safe en route altitude before proceeding on course.

A hold may be specified in an Obstacle Departure Procedure (ODP) with only a textual description provided.

Standard Terminal Arrival procedures may depict holding patterns that ATC might use to facilitate the flow of traffic.

Many instrument approaches provide a holding pattern to allow you to reverse direction and get aligned with the intermediate or final approach course segment.

A hold is an idealized race track pattern anchored over a holding fix that the pilot can identify with on-board electronic navigation equipment, but the path you end up flying is usually not a perfect racetrack pattern. ATC can't really tell how accurately you're flying the hold. Center radar sweeps about every 12 seconds and a lot can happen in that time period. Approach radar sweeps more frequently, but approach controllers are too busy to spend time critiquing your holding prowess. In my experience, ATC doesn't really care how accurately you're flying a holding pattern as long as you stay at your assigned altitude in the general holding pattern area.

Holds can be over a VOR or Locator Outer Marker, they can be at the intersection of two VOR radials, or they can be on a VOR radial at a specific DME distance.

I often see pilots who try to fly the racetrack in the wrong direction, so let's be clear: Once you are established in the hold, you'll always fly the inbound course toward the holding fix. The turn to the outbound course occurs after crossing the holding fix. The outbound course is located on the holding side and is particularly important when determining the holding pattern entry because you fly to the holding fix and then turn outbound. More on that later.

The term protected side was formerly used to describe the side of the inbound course where you don't usually fly while holding, but this term was not very accurate. The protected airspace around the hold is fairly large and extends well into the non-holding side of the pattern and if you're interested in the gory details of holding pattern construction, check out Order 7130-3A. The preferred terms are now the holding side and the non-holding side. If you stray into the non-holding side you are not going to fly into a mountain or be eaten by a dragon, provided you maintain an appropriate altitude (dragons can't fly very high) and observe the maximum speed for your altitude.

The speed you fly in the hold is important because you want to stay in protected airspace. The usual holding speed limits are 200 knots below 6,000' MSL, 230 knots between 6001' and 14,000' MSL, and 265 knots at 14,000' and above. These speeds are clearly faster than the cruise speed of many light, GA aircraft, but you should still slow down to reduce your fuel consumption.

Holding patterns can be put into two broad categories; published and ad hoc. Published holds, as shown above, may be part of a SID, ODP, STAR, an instrument approach procedure, or they may even appear on an en route chart. Ad hoc holding instructions are made up by ATC on the spur of the moment and while this is rare, it's still something every instrument pilot should be prepared to handle.

Many modern GPS receivers will display hold patterns that are part of a SID, STAR, or instrument approach procedure. The GPS may even suggest the entry procedure. Autopilot-equipped aircraft with newer GPS receivers can even enter and fly the hold for you. Only one GA GPS receiver that I know of, the Garmin GNS 480, allows you to program an ad hoc hold. The bottom line is that your GPS receiver, if you have one, may or may not help you with the entry to the holding pattern. You should be prepared to figure out and fly the holding instructions that ATC throws your way using your little gray cells. More in the next post ...

Thursday, March 05, 2009

Refreshing Paws

For readers who noticed an earlier lull in my posting frequency, I was busy preparing for two new arrivals - ages three and four.

It's been almost a year since the passing of our basenji Hunter and as the old saying goes "A home without a dog is just a house." While these two knuckle-heads may look sedate, appearances are deceiving. When they are not snoozing, I often refer to them as the Pandemonium Twins.

We adopted them through Basenji Rescue and Transport, a great organization if you're considering being owned by a basenji.

Sunday, March 01, 2009

Uncertain Conclusions

This post concerns serious business, so I'll start with some levity.
A salesman, a hardware engineer, and a computer programmer were in a company car traveling down a steep mountain road when the car's brakes gave out. Miraculously, the driver was able to bring the car to a stop by turning off the engine and using the emergency brake.

As they piled out of the vehicle to assess the damage the salesman declared, "We should call the company carpool and have them dispatch us a brand new company car."

The hardware engineer shook his head and said, "No, we should take this car apart, find out what went wrong, get new parts, and fix this car."

The programmer rolled his eyes and opined, "No, no, no. We should take this car back up the hill and see if it does it again."

There are limits to inductive reasoning, especially when one tries to draw conclusions based on a very small sample of events. It's easy to draw a conclusion from experience, but that conclusion could be invalid or incomplete, depending on your experience and, among other things, luck. Pilots often receive in-depth training in aircraft systems and that can lead them to believe they can troubleshoot or fix problems in flight, but don't forget an important part of aeronautical decision making: Have a solid respect for what you don't know and avoid making unnecessary and risky assumptions.

Consider the procedure for resetting a popped circuit breaker while flying an aircraft, a practice that is now virtually prohibited in commercial aviation but may still be widely practiced in general aviation aircraft. A related problem involves flying an aircraft with non-essential, inoperative equipment that hasn't been removed or deactivated. The NTSB has concluded that both of these issues likely led to the crash of the Cessna 310 I mentioned in my last post.

Like many things, the FAA's regulations don't make the process of dealing with inoperative equipment a simple matter. There are seven (count 'em!) steps you may need to follow to be legal.
  1. Does the aircraft in question have a minimum equipment list (MEL) and, if so, is the thing that's inoperative required on the MEL? If yes, the aircraft is grounded and corrective action is required. If no, then skip to step 6. If your aircraft doesn't have an MEL, then ...
  2. Does the thing that's inoperative appear in the aircraft's original equipment list as being required for certification? If yes, the aircraft is grounded and corrective action is required. Otherwise ...
  3. Does the thing that's inoperative appear in the aircraft's Kinds Of Operation Equipment List (if the aircraft has one) found in the Limitations Section of the AFM for the planned type of operation? If yes, the aircraft is grounded and corrective action is required. Otherwise ...
  4. Is the thing that's inoperative required by 14 CFR 91.205 for the planned type of operation? If yes, the aircraft is grounded and corrective action is required. Otherwise ...
  5. Is the thing that's inoperative required by an Airworthiness Directive? If yes, the plane is grounded and corrective action is required. Otherwise ...
  6. Do you, as PIC, believe that safety of flight will be adversely affected by the thing that is inoperative? If yes, the aircraft is grounded (see Sam's blog for a great description of a PIC's real life safety-of-flight decision). Otherwise ...
  7. Deactivate or remove the thing that is inoperative, placard it as inoperative, make a maintenance log entry describing what you did, and you can now go flying.
An important thing to consider is "When did the thing that is inoperative actually quit working?" Often you'll discover something is broken during your preflight inspection, taxi check, or during the before takeoff checks. If you discover something is broken while in flight, you should tell someone and make a record of the discrepancy after you complete your flight. This discrepancy report (US pilots often call them squawks) should alert the pilot who is scheduled to fly the aircraft next, provided that information is recorded somewhere and communicated to maintenance personnel and the next pilot(s).

The FAA tries to incorporate these maintenance concepts in the various Practical Test Standards under the Emergency Operations and Postflight Procedures areas of operation. In my experience, few GA pilots actually complete a postflight inspection after flying. Heck, with some pilots you're lucy if they remember to tie the plane down, install the gust lock, and so on. Many designated pilot examiners will thoroughly quiz a candidate about required equipment and the handling inoperative equipment, but a lot of pilots seem to forget these procedures as soon as the ink is dry on their temporary airman's certificate. Even the very experienced airline transport pilot involved in the Cessna 310 crash seems to have overlooked the proper procedure for handling inoperative equipment.

A maintenance discrepancy log sheet recovered at the accident site, annotated during the previous day’s flight, described the weather radar display as going “blank” during cruise flight, accompanied by a “smell of electrical components burning. Turned off unit - pulled radar [circuit breaker] - smell went away.” No corrective action was annotated next to the discrepancy write-up, and no evidence was found to indicate that corrective action was taken prior to the mishap flight.

Post accident interviews with company personnel indicated that during a phone conversation the day prior to the accident, the ATP was made aware of the weather radar discrepancy item. A company aircraft mechanic confirmed that the ATP stated that he “didn’t care about the radar” during a telephone conversation on the morning of the accident.

None of the company personnel interviewed remembered seeing either member of the accident flight crew reviewing the airplane discrepancy log prior to departure, but one mechanic did recall that the ATP performed the preflight inspection of the airplane.

The pilots decided to take the plane without thoroughly investigating the squawk about the radar and it appears the circuit breaker that had been pulled was not "collared" by maintenance to prevent it being reset. Resetting the circuit breaker may have caused the Cessna 310's in-flight fire. Here's how.

Older style circuit breakers use a bimetallic, thermal design that responds to the heat generated when a specified electrical load is exceeded. A metal collar holds the circuit closed against the force of a spring contained inside the circuit breaker. Should the collar begin to heat up, it will expand, allowing the spring to open the circuit. This design generally works, but it has two problems.

Old circuit breakers may no longer perform as designed, especially if they have accumulated a coating of dirt, dust, or some sort of spilled contaminant like coffee or soft drinks.

Even if circuit breakers aren't contaminated, an arcing event between wires whose insulation has chaffed away may not generate enough heat at the breaker to cause it to open immediately. Significant arcing damage may occur and significant smoke can be generated before a conventional circuit breaker will trip. Arc-Fault Circuit Breakers are now available which can detect arcing events and immediately open the circuit before significant damage occurs, but you can bet that 70's, 80's or 90's vintage aircraft are probably not equipped with such devices.

According to AC 120-80, most hidden fires are the result of arcing between bundled wires. Uncontaminated wiring insulation is fire resistant, but an arc can easily provide a source of ignition for surrounding insulation materials or even wiring insulation if it has been contaminated with dust/dirt or stray corrosion inhibitors and lubricants. Once a circuit breaker trips, you may very well be confronted by an electrical system in an indeterminate state: The AFM's wiring diagram may no longer apply to your aircraft.

The problem is made worse by the fact that some aircraft designs put circuit breakers in very difficult-to-reach places. The Caravan has numerous rows of circuit breakers located on a panel adjacent to the pilot's left leg, leading some operators put color-coded plastic collars on important circuit breakers to help pilots figure out which circuit has opened. The Cirrus SR20 and SR22 have circuit breakers that are located near the pilots right foot in a location where parallax makes it virtually impossible to accurately read the labels while flying the aircraft. Piper Comanche and Twin Comanche aircraft have circuit breakers behind a trap door on the floor, another illustration of a fundamentally bad design decision.

Did the pilots of that Cessna 310 reset the circuit breaker for the radar equipment that had previously been pulled (but not collared) by the previous pilot? We may never know.
At 08:32:50, shortly after reaching a cruising altitude of 6,000 feet, the flight crew declared an emergency to the Orlando International approach air traffic controller (ATC). The crew advised that there was "smoke in the cockpit," and announced their intention to land at SFB. ATC cleared the airplane to fly directly to SFB and descend to 2,000 feet. Radar data indicated that the accident airplane turned toward SFB and commenced its descent. ATC then cleared the accident crewmembers to “to land any runway." The last radio transmission from the airplane occurred at 08:33:15. It was terminated in mid-sentence and appeared to include the phrase “shutoff all radios, elec.” The last radar return from the accident airplane was at 08:34:50, about 1/2-mile
east of the accident site.

GA pilots can learn a lot from this accident by following a procedure for fires and tripped circuit breakers that the airlines generally follow, as outlined in AC 120-80. First, be aware of the indications of hidden fires:
  • Odors of smoke or of hot electrical equipment
  • Un-commanded operation of an aircraft system may indicate a hidden fire
  • Circuit breakers tripping
  • Hot spots on the floor, or behind sidewalls and access panels
  • Smoke or visual signs of flames
Should a fire develop, be prepared to follow these steps:
  • Fight the fire immediately, be aggressive
  • Try to find the base or source of the fire
  • Do not reset circuit breakers unless the equipment is required for safe flight
  • Plan for an immediate descent and landing at the nearest suitable airport
  • Use personal breathing equipment (supplemental oxygen) if available
Be wary if a circuit breaker trips and try to apply all that systems knowledge you learned once you are safely on the ground. Knowing the signs of in-flight fires, how to properly handle inoperative equipment, leaving tripped circuit breakers alone, and being familiar with using fire extinguishers may save your life some day.