Monday, October 22, 2012

Where There's Smoke... (Part I)

Date Aircraft Route of Flight Time (hrs) Total (hrs)
22 Oct 2012 N21481 5G0 (LeRoy, NY) - 1B1 (Hudson, NY) 2.0 1098.4

The Experiment

Five hundred feet off the ground, I went under the hood.

"Clear both ways," assured Darrell, riding in the right seat as safety pilot.  I watched the #1 CDI for signs of intercepting V252, the 314° radial off of the Geneseo VOR and my most well-traveled airway.

A constant headache in my instrument training has been tracking this radial.  Routinely, while established on this airway in level flight with an appropriate crab to correct for wind, the CDI needle would abruptly swing from centered (on the radial) to full deflection (way off the radial).  At first, I thought it was just me.  As time went on, I began to think otherwise.  Unfortunately, this meant that I started to lose confidence in my equipment.  The only thing possibly worse than not trusting your instruments while IFR is relying on instruments that are not actually trustworthy!

For our experiment, the #1 CDI was driven by the GPS in "OBS" mode, manually set to the 314° radial off of Geneseo.  This is a function that the Kings refer to as a "super VOR".  In this mode, the GPS acts like a VOR receiver, but the signals are purely satellite-based.  Thus, the #1 CDI would indicate the closest thing to "truth" that I had available to me.  The #2 CDI was set to the same radial as received by the KX-170B #2 navigation radio.

My interception of V252 was quite possibly the most crisp one I have ever made.  Ten miles northwest of the VOR at 5500', we were centered on the airway according to the #1 CDI.  The #2 radio-driven CDI agreed, for a time.  Then, the #2 needle lazily drifted to full deflection, showing me to be well off the airway.  No wonder I have been wandering around the sky while tracking the Geneseo VOR!  We were high enough and close enough to the VOR (five to ten miles) that the nav radio should have been as accurate as it ever gets.

Because the GPS unequivocally showed me to be on the airway, the issue was certainly not one of poor piloting skill.  Past experimentation has demonstrated that both nav radios exhibit the same behavior, so the radios themselves are also unlikely to be the problem.  Therefore, something is aberrant about either the transmitted signal from the VOR or my reception of that signal.

Darrell noted that he had never observed such behavior while flying the same route in his airplane.  Although his anecdotal data seemed to exonerate the VOR, we agreed that he should repeat today's experiment with his airplane the next time he flew.

I reached the Geneseo VOR satisfied that we had performed a valuable troubleshooting experiment.  Crossing the station, I turned outbound on a new course toward Ithaca.

The Mission

My goal for the day was to log some prolonged flight time under the hood.  In the process, I would get lots of practice tracking airways and some opportunity to fly practice instrument approaches.  Considering the results of our experiment, I elected to track those airways using the GPS in "super VOR" mode.

Our ultimate destination was Groton, CT where I had arranged to meet a handful of friends and former colleagues for lunch.  I had not seen any of them in the seven years elapsed since the Kalamazoo diaspora.  One of them was my former supervisor, Leslie, from whom I received my first promotion and some invaluable advice on decision-making that I actively use to this day.  My suggestion of a lunch gathering inspired a delightfully (dare I say surprisingly?) enthusiastic response.  Though I was happy to be flying and thrilled to have made some progress in troubleshooting the bizarre behavior of my navigation radios, I was most excited about seeing my old friends.

Our course took us from the Geneseo VOR, to the Ithaca VOR, to the Rockdale VOR.  From there, I planned to go GPS direct to Colombia County Airport (1B1) and perform a GPS instrument approach there on runway 3 or 21 as dictated by the wind.  Columbia County was chosen as a fuel stop because they had the least expensive fuel I could find and, knowing my physiology as well as I do, it would also serve as a perfect restroom stop.

The Anxiety

We flew our planned route, passing from radar facility to radar facility.  All was going well.  There was little chatter on frequency this Monday morning, though Boston Center was certainly busier than Rochester, Elmira, or Binghamton had been.  We were about forty minutes west of Columbia County Airport when I realized that a restroom break would definitely be required by the time we landed.

Around this time, Darrell noted that there were clouds ahead.  He was unsure how far the deck extended and thought that an altitude change might be necessary, but was not entirely sure.  We debated the merits and risks of going over versus going under.  On the one hand, we did not want to be trapped on top and unable to land at Columbia County, but we were also rapidly approaching the Catskill Mountains and I did not want to be squeezed between terrain and clouds.

I have been flying VFR cross countries for the better part of a decade and have become very comfortable with what writer Lane Wallace once referred to as "sniff-testing" my way through weather.  Not being able to see the clouds ahead robbed me of the ability to synthesize observation with experience (or pilot intuition, whatever) to develop a plan with an appropriate way out (always, always leave yourself a way out).  As I tried to devise a plan with Darrell as my eyes, I felt my chest clench in the grip of anxiety over my inability to directly, visually, assess the situation.  This sensation actually spawned more anxiety; it is rare for me to be anxious while at the controls of Warrior 481 and that made me even more anxious.

I decided to descend to 3500 feet while turning slightly to the north to avoid the higher terrain around the Catskills.  Level at 3500 feet, Darrell noted that we were not low enough to pass beneath the ceiling.  For the first time, I peeked out the windscreen from under the hood.  He was right.  I decided to go over the deck and we climbed to 7500'.  With the terrain no longer a factor, I adjusted our course back to a direct heading for Columbia County.

Weather reports out of Albany and Columbia County, once we were close enough to receive them, reported both fields to be overcast at 3500'.  We had plenty of fuel on board and the Atlantic coastline was clear of clouds.  Proceeding directly to Groton was a viable option.

However, I really needed a restroom break (traitorous bladder).  When I expressed this to Darrell, he noted that he was experiencing the same level of discomfort.  As we continued toward Columbia County, Darrell reported that there might be some holes in the deck suitable for a legal VFR descent.  He suggested I turn a bit.   My chest tightened in the grip of anxiety again.

I pulled off the hood (or thought I did) and looked outside, which completely dispelled the anxiety.  Through a massive hole to the southeast, we could see sunlight sparkling on the nearby Hudson River.  As we drew closer, more of the river came into sight surrounded by farmland and autumn foliage.  Near the edge of the void in the clouds, still shadowed under the overcast, was a muscular swell of Earth marking the east rim of the Catskills.

It was an amazing sight, but the camera was just too far out of my reach.

The Fuel Stop

Sufficiently distracted by a recalcitrant bladder, I dropped plans to fly a GPS approach into Columbia County.  Descending, the airplane bounced in abrupt chop where the westerly winds roiled over the peaks of the Catskills.  Though the automated weather broadcast at Columbia County advertised winds at four knots, I flew the final approach while crabbed significantly.  The airplane abruptly dropped a wing as we descended through treetop level, drawing a gasp of surprise out of Darrell.  I corrected smoothly and planted the upwind wheel on the runway in a firm, but respectable crosswind landing.

On the ramp, the fuel pump had two airplanes crowded around it.  We parked nearby, careful to provide a clear path for both to taxi away.  As I shut down the airplane, I realized that I was still wearing the hood and had been simply tilting my head upward to see outside.  Chagrined, I pulled it off and tossed it onto the glare shield.  Then we both hastened into the terminal building to deal with our vexing biological limitations.

While inside, we lost our place in line for the fuel pump to a Cessna 180 on amphibious floats (we were "budged", as they say in New York).  Perched atop its ponderous floats, the high wing airplane towered over the other aircraft on the ramp.  In order to reach the fuel tank, the guy fueling the airplane had to stand on the very top of the available step ladder (i.e., the yellow part that says "do not stand").  Unfortunately, the ladder legs were not fully square and the ladder wobbled under its occupant.  I ran over and steadied the ladder, squaring the legs.  I hoped that the fellow above me did not overfill his tank; I was not in the mood to bathe in 100LL that morning.

Prior to 2012, I would not have considered $5.59/gal to be a reasonable fuel price, but it was the best I could find along the route.  Once the Warrior was fully fueled, I allowed the fuel to settle for a few minutes.  We had plenty of time - a brisk tailwind had swept us eastward far faster than planned.  Despite a late departure from Le Roy, we would actually land early at Groton.  While we were on the ground at Columbia County, the cloud cover largely disintegrated.  We were set for a smooth, easy flight to Groton.

We climbed back into the Warrior and buckled in.  Upon engagement, the starter vigorously spun the propeller, but the engine showed no interest in starting.  I had not primed the engine, expecting it to have been warm enough to start easily.  I added a single shot of prime and tried again.  This time, the Lycoming showed some mild interest in combustion that terminated in a muffled popping sound.

Still cranking, I looked at Darrell.  "Backfire?"

Darrell nodded.  "I think so."  I continued cranking.  Should a backfire occur, the goal is to keep cranking the engine to pull any flames inside the engine, rather than allowing them outside.  Fire on the outside of an engine is bad news.

I wondered if the engine could have somehow become flooded (it did not seem likely from a single shot of prime), but nevertheless reversed throttle and mixture positions in the flooded start procedure.  Nope, no interest in starting.

I finally released the starter.  "Let's give the starter a rest for a few minutes and try again."  As I looked out the windscreen I thought I saw something.  A ghost, an insubstantial tendril, that emerged from the front of the cowling.  In the steady breeze blowing across the ramp, it vanished almost as quickly as I saw it.


I looked at Darrell.  "Get out. Now."

The Fire

I swept one hand across the instrument panel, killing the electrical system, as my other hand unfastened the seat belt shoulder harness.  Darrell and I clambered out with haste, coming to stand directly in front of the airplane.  I saw no more smoke.  Stepping closer, I peered through the openings in the front of the cowling.  I could discern no evidence of smoke or fire.

Opening the cowling held the danger of feeding oxygen to a nascent fire, but I did not know how else to assess the situation.  I unlatched the left side of the cowling, stood back, and carefully lifted it just enough to see inside.

Small, orange flames danced on the rubber grommet residing on the back of the carburetor heat airbox.  I felt my stomach knot and visualized my beloved airplane as a melted pile of slag sitting on the ramp at Columbia County.

Darrell rushed over with a fire extinguisher.  It was the dry chemical type known to be very corrosive to aircraft.  "I don't really want to pull this handle," Darrell commented.

"Neither do I." I said.  The fire was not spreading, seemingly confined to the now-deformed rubber component on the back of the airbox.  Within a minute, it extinguished itself.

The Game of Telephone

My first instinct was to call my friends in Groton to cancel lunch.  Unfortunately, our plans were formed completely over email and, though I had sent my phone number on to everyone in Groton, I did not have their phone numbers.  I called a friend and fellow Kalamazoo expatriate in Rochester who would have Leslie's contact information.

"Can you contact Leslie and cancel with her?  We just had an engine fire."

Stacey dutifully contacted Leslie and notified her that we were not coming.  Unfortunately, my vague (and, honestly, still adrenaline-muddled) details on what had happened left significant room for nervous, imaginative extrapolation.  Before long, friends in both Rochester and Groton were worried that we had experienced an in-flight engine fire and crashed.

The Assessment

I was thankful that we chose Columbia County for our fuel stop rather than some unattended field with only a self-service pump.  The engine needed to be examined by someone knowledgeable before I would even think about trying to start it again.

Stranger in a strange land: Warrior 481 parked under a Gulfstream belonging to the owner of the Mets.

We quickly found Mike, one of the mechanics on the field, who arranged to have Warrior 481 towed into the maintenance hangar for an assessment.  Inside, Mike, Bill, and Sal (the head of operations for the shop, if I understood correctly), discussed the issue with us.  Part of the difficulty was that they are a Part 135 shop specializing in turbine aircraft.  None of them really considered themselves carburetor experts.  They called their piston engine guru at another facility for advice.

Sal quickly described the concerns.  "That carb is going to need to come off and be sent in for inspection."  He noted that the venturi could be melted or distorted, that a lead seal could melt and disappear entirely, and that the nozzle for the accelerator pump is held in place with Loctite such that excessive heat from a fire could loosen it.

While Mike began to decowl the airplane, Darrell called his mechanic, whom my daughter refers to as "Helicopter Ray".  I called Jim at my shop.  Both Ray and Jim agreed that, while removal of the carburetor and sending out for inspection was not unreasonable, they thought that decision was premature without an inspection.  Jim told me to check the air filter, hoses, fuel lines, engine controls, and carburetor interior for damage.  If none was found, he recommended fixing the melted component on the airbox, ground running the engine to check for other issues, and flying it home.  "Helicopter Ray" was of a similar opinion.

I helped Mike remove the cowling.  Once the hoses going to the airbox were removed, he used a flashlight and a mirror to inspect the interior of the carburetor.  "You didn't have much of a fire here," Mike noted as we looked inside.  The interior of the carb was a dull metallic gray.  Nothing was charred, melted or distorted.  The lead seal mentioned by Sal was not actually installed on my carburetor; mine used a brass plug instead and it was undamaged.  Once he removed the airbox, Mike was able to verify that the accelerator pump nozzle was firmly seated.  In short, the only detectable damage to the airplane was the little rubber grommet on the back of the airbox that was ground zero for the fire.

It appears that continuing to crank after the backfire probably saved the engine.  Consensus among the mechanics was that the carburetor was fine and that the next course of action was to replace the melted parts of the airbox and get the airplane back in the air after a ground run.

Relieved, Darrell and I borrowed a crew car and drove to lunch where Darrell ingratiated himself to our waitress right away by calling her "sir".  It was just that kind of a day.  But the hamburgers were good.

The Headache

Although I was ready to arrange a rental car for a multiple hour drive back to Le Roy, Darrell called Ed, one of the other Le Roy pilots.  Ed generously agreed to pick us up in his Arrow later that afternoon.  Stranded, Darrell and I found ourselves sitting in the terminal building with a long, boring afternoon stretching before us.

Darrell shook his head.  "Seeing that fire on the back of your engine..."  He trailed off meaningfully.

"I know," I said.  The knot in my belly was only just beginning to loosen.

Then, I was paged to the shop.

Mike, Bill, and Sal were standing around a table where the airbox had been disassembled.  "This airbox has nonstandard components in it," Sal informed me accusingly.  Indeed, Jim and I had rebuilt much of the airbox a few years earlier after discovering that it was leaky and worn.  Sal went on to inform me that they were a Part 135 shop (dealing with commercial operations and thus subject to a higher standard) and they would not sign off on any non-standard components despite the fact that the box, as rebuilt by Jim, was completely legal. Though he conceded that there was nothing mechanically wrong with nonstandard parts in this application, he invoked the "L-word" (liability) frequently.

Yes, lawyers are still doing their best to kill aviation in this country and guys like Sal are justifiably wary of them.

I was appalled, however, when he held up the carburetor heat flap assembly.  The metal shaft was bent.  I knew that Jim would not install a bent component in the airplane.  In fact, I had assisted him in that work and would have noticed if it was bent when installed.  Conversely, I could not conceive of any strain being placed on the shaft in situ that could bend it, either.  My best guess is that the fire on one end of the shaft softened the metal enough that any stress imparted by the flap assembly clamped to it may have caused it to bend.  But I will never actually know what happened.

After some research, we learned that the official Piper parts would cost approximately $600 plus labor to assemble and install them.  Then, Sal offered another way out.  If I took the airbox home with me, had Jim repair it and sign it off, that would address their liability concerns and they would gladly hang it back on the airplane.  I called Jim and explained the situation.  On the phone, Jim was uncharacteristically annoyed and I understood why; this other shop was effectively questioning his workmanship.

In the end, we agreed that Jim would fix the box, sign off on the repair, and it would be reinstalled on the airplane at Columbia County.

Through it all, Mike was cool and helpful, supporting my decision to have Jim fix the box rather than ordering $600 worth of overpriced metal components.  He promised me that the Warrior would remain inside and be well cared for until I could return.  With this assurance in hand, I took one final look at my ship, then left the shop

I returned to the terminal building, bearing with me both a cardboard carton of airbox components and a splitting headache.  While I understood and appreciated the shop's liability concerns, the mental whiplash of going from panic (fire!) to relief (no damage!) to quibbling over real or perceived liability risk had wiped me out for the day.  I slumped into a chair, relayed the story to Darrell, and tiredly watched an avatar of Ed's airplane creep toward us on FlightAware.

The Rescue

Shortly after five o' clock, Ed's Piper Arrow touched down at Columbia County in a strong direct cross wind.  "Four knots, my ass," he muttered in reference to the field's automated weather reporting station.

"I warned you that it lied," Darrell reminded him.  "It lied to us, too."

As the setting sun reddened the western edge of the world, we pressed homeward against a brisk headwind to arrive in Le Roy over an hour after dark.  I paid to top off Ed's fuel tanks and Darrell volunteered to deliver the airbox to Jim in Batavia the next morning.

As expected, Ray was waiting for us in the airport office.  Ray always maintains vigil at the airport when any of his tenants has a crisis.  I described what happened and explained the corrective actions that I took.  Ray concurred that I had taken the appropriate actions after the backfire and probably saved the airplane in the process.

When the discussion began to ebb, I excused myself to begin the commute back home.  It was going to be a long drive.

The two weeks that followed would be even longer as Hurricane Sandy bore down on the northeast.

Monday, October 8, 2012

Timer, Not Forgotten

Date Aircraft Route of Flight Time (hrs) Total (hrs)
08 Oct 2012 N21481 5G0 (LeRoy, NY) - local 1.2 1094.8

It has been weeks since my last time under the hood and well past time to get back on the IFR horse.  Darrell was available for safety pilot duty, the weather was good, and the airplane was fueled and ready.  There was absolutely no excuse not to go out and fly blind this afternoon.

Though I have not been flying instruments, I have spent a lot of time thinking about flying instruments.  One thing that I have realized is that I need to internalize the process of flying approaches.  The specifics don't really matter.  For today, I decided that the Le Roy VOR-A would be the best way to accomplish this goal without wasting a lot of gas.  Darrell and I shot the VOR-A into Le Roy twice and, finding ourselves with time to spare, did an impromptu load of the newly-commissioned RNAV-28 approach.

It was bumpy today and I worked hard to maintain altitude to the PTS standards, but was generally successful.  VOR tracking was crisp and both VOR approaches were well-flown.  In fact, upon crossing the final approach fix each time, I remembered to start the timer.  Angels sang and fireworks exploded; there was much rejoicing.

Compared to the VOR-A approach, the GPS approach is stone simple.  My only issue?  Upon being instructed by the GPS to turn onto the 284° final approach course (which appeared as an LNAV+V with vertical guidance), I became fixated on the directional gyro.  While fixated, I stayed on heading while the northwesterly wind blew me off course.  The GPS-slaved CDI, of course, displayed the increasing course deviation unnoticed by me until Darrell decided to say something.  With the spell broken, I turned on course, flew the approach to minimums and landed.  The landing was a total greaser and was punctuated by some approving sounds from Darrell.

A post-flight review of the GPS ground track reveals every issue I noted while flying today:

1.  My Garmin 430W VOR receiver struggles to pull in the Geneseo VOR signal after departing Le Roy.  As a result, the initial turn toward the VOR is a bit sloppy, but tightened up as we gained altitude and neared the VOR.

2.  I inadvertently flew one of the course reversal teardrop patterns ten seconds too long.  There's no hiding that in the GPS data.

3.  I flew the RNAV-28 well except for the very obvious dip in the westbound course line at the top of the above figure.

Item 1 is a limitation in my instrumentation.  Both items 2 and 3 were my fault and resulted from fixation.  I need to work on keeping the scan going continuously.  It was a good lesson and a manageable issue to overcome.

Today was a great confidence builder and I ended the flight feeling good.  Despite the fixation issues, I managed to stay ahead of the airplane.  In fact, I felt more ahead of the airplane than I have ever felt while flying approaches. 

But much more practice is needed.  Next time, I will tackle some more complex approaches and see how I do.  To date, I have 21.4 hours simulated instrument time, 0.3 hours actual instrument time, and 13 approaches under my belt (a mixture of VOR, ILS, and GPS).

Slowly but surely...