Wintertime Partial Panel in IMC

For many years the instrument approach plates for Lebanon, New Hampshire, posted an ominous footnote: "Caution-hazardous terrain all quadrants." For some reason this warning no longer appears, though I'm reasonably certain the mountains haven't moved much. There still isn't any radar coverage in the area and many of the approaches feature old-fashioned procedure turns. This is the only place we go regularly where our approaches are unsupervised by helpful controllers.

It is a few days before Christmas as I preflight our Cheyenne in Tampa in preparation for the trip to New Hampshire. DUATS has predicted a flight time of four hours and 38 minutes for the 1,100-nautical mile flight. This tells me that there isn't much help from the winds. The forecast is for overcast skies with limited visibility due to haze and mist until 5 p.m. After that freezing rain and lowering ceilings are in the cards. Since our endurance is five and a half hours, I accept the need for a fuel stop. Sometimes we go non-stop, but only when the destination weather is clear and we get a little bit better boost from the winds.

It is a beautiful but sad morning in Tampa. Our old football coach of the Buccaneers, Tony Dungy, has come back to town by Gulfstream because his son has been found dead here. I recognize the airplane with its Indianapolis Colts' logo on the tail and I notice that the crew is preflighting their airplane as I am doing the same with ours. "Are you taking the coach back to Indianapolis?" I ask. Yes is the answer. "Please give him our sympathies; he seems like a really nice man," I say. "The whole family is wonderful. It is just so sad," says the Gulfstream's flight attendant. One of the pilots says to me, "Fly safe." "You, too," I respond. It is a quiet moment of perspective for all of us, shared on the ramp in the shade of two magnificent machines.

I file for Greenville, North Carolina, as a fuel stop. With any luck we'll beat the freezing rain to the Lebanon airport by two hours. This is not the last good decision I'll make today.

With our packages stowed, coffee pot full and flight plan stored in the Garmin GPS, my wife and I start out, step climbing to Flight Level 200. Cathy sits in the back, facing backward, headset on, reading the morning newspaper's story about the Dungys. Thirty minutes later, Jacksonville Center clears us direct to KPGV, climb and maintain requested altitude of 230. "Thanks for the Christmas present," I say, noting that nobody seems reluctant to say "Merry Christmas" on the center frequency.

I enter 230 into the altitude preselect, sit back and admire the view. There's Jacksonville to the right. It is clear for the next 700 miles, thanks to a large area of high pressure over the southeast. I'm jolted from this reverie by a sudden pitch up followed by an immediate pitch down. I scramble to disconnect the autopilot. We level off, with lots of retrimming, at 22,900 feet. Cathy has screamed, but I wait until we're level before I explain that the autopilot developed a mind of its own. She is frightened and my consoling doesn't accomplish much. I don't know it, but there is more to come.

I cautiously hit the altitude hold button and see the flight director's command bars stabilize appropriately. I engage the autopilot with my thumb poised over the disconnect button. I promise Cathy that I'll keep a finger on that button for the rest of today's flying. I think back to my annual FlightSafety training. Aren't there five ways to disconnect the autopilot? I can think of electric trim switch, disconnect button on each yoke, the autopilot switch and the circuit breaker. We fly along. Occasionally the command bars hiccup up but settle right back to level flight, which makes the airplane feel like it has just gone over a small speed bump. Cathy seems not to notice.

A tailwind develops and I flirt with the idea of going nonstop. The Lebanon weather is displayed on our Avidyne EX 500: "2,700 feet overcast, 4 miles visibility in haze." I change our destination from Greenville to Georgetown, Delaware, which gives me more time to think about the appealing idea of a non-stop flight. Everything seems to be working okay now.

An hour later I chicken out. We land, refuel, and refile at KGED. Soon we're climbing over the New Jersey coast, heading for the tip of Long Island. It is still clear and I watch the string of jets heading for Philadelphia to our left. When we reach our assigned altitude of 210, I hit the alt hold button. The command bars stabilize and I engage the autopilot. It is -20ºC outside. So far, so good.

Over Connecticut an undercast forms, looking like a dirty gray fleece blanket. We've got a good tailwind now and I start second guessing my decision to stop for fuel. Lebanon's weather is holding up. I enter the ILS 18 approach in the Garmin and call up the approach plate on the Avidyne's JeppView. When it comes to Lebanon, Boston Center can get you down to 4,700 feet, but that's it. If you don't see the airport, you can anticipate an instrument approach. I review the altitudes: 3,900 feet for the procedure turn outbound, 3,500 when established inbound, 2,900 at the Final Approach Fix, called BURGR. (Two other fixes on the approach are HAMMM and FRYYS, get it?) The decision altitude is 955 feet, which should be of no concern.

Eighty miles out I get the ATIS. All is as I expect: 2,700 feet over, 4 miles, ILS 18 in use. Boston Center starts us down and we enter a wet mass of cloud, tops about 19,000 feet. The cloud is not thick and is a reddish-brown gray in color. There will be nothing more to see out the windshield until we're on final. I tune in the localizer frequency on the Garmin and then, in a moment of uncharacteristic carefulness, I also tune the number two nav to the same frequency and I realign the copilot's gyro compass. This compass is not slaved like the one on the HSI right in front of me. It precesses like crazy and I never look at it. My finger is still hovering over the autopilot disconnect button. I turn on the windshield heat and watch the wet compass turn 30 degrees due to the electrical field.

Boston says descend maintain six, cleared direct to BURGR, but expect to maintain 6,000 as there is traffic on the ground at Lebanon and we can't be cleared lower until he's in radar contact. A wrinkle in the fabric of my carefully rehearsed approach has appeared. I start thinking about losing 2,100 feet in the procedure turn when the flight director command bars just pull up and disappear, like a curtain rising at a play. This disconnects the autopilot automatically and introduces more drama than I'm eager for. I think, "Well, the autopilot wasn't working all that great this trip, so I'll just plan on hand-flying the airplane and using raw data for the approach." I retrim the airplane and try idly to retrieve the command bars. They reappear, but when I push the heading select button, they withdraw again.

Just as I intercept the localizer out- bound, the HSI starts spinning like a cheap child's top. A compass flag descends telling me that the HSI is no longer reliable. The artificial horizon appears to be working as it agrees with the standby horizon and with the copilot's horizon. The only apparently working compass is now the copilot's, way over there on the right side and not that easy to see with these damn bifocals. I contemplate turning off the windshield heat and using the easier to see wet compass, but, when I look up I see ice on the unheated portions of the windshield. I reason that I want a clean window if I ever get us out of this mess.

Boston clears us to 3,900 feet and okays the procedure-turn outbound. I set the Avidyne to the chart page, where I can see our airplane bug tracking outbound on the localizer. Can I make the appropriate turn to 052 degrees with this set of instruments? Will something else quit in the next minute? Should I just add power and climb back into radar coverage, keep the airplane level and get vectored to a VFR airport and pass up this procedure-turn excitement? I am silently glad that we stopped for gas, but I am too busy to look for the HSI circuit breaker.

Looking over at the copilot's compass, I turn right, vowing to maintain 4,700 feet until I am established on the localizer inbound. Our little airplane makes a perfect turn and covers the outbound track on the chart. A minute later I start the inbound turn, being very careful to make the turn standard rate. I hate to admit it, but I almost always use the autopilot heading bug for these maneuvers. Not today.

The HSI localizer indication may be working, but I can make no sense of it as the compass rose rolls around like the death throes of a dying salmon. I am thankful that, in a moment of bored carefulness, I tuned the number two nav to the localizer. I level out on what I think is a heading of 232. The localizer needle does not appear to move, however. I look up at the chart page and see that I have overshot the turn and we are turning east, away from the localizer. I make what I think is a 30-degree correction to the right. Several years ago a Lear Jet with everything functioning got lost doing exactly what I'm doing right now. Local pilots predicted that the airplane would be found the following autumn during the hunting season, but it was several years before it was discovered.

The localizer needle centers, I deploy 15 degrees of flaps, the gear, and a deep exhale of breath. I would never have continued the approach but for the situational awareness provided by the JeppView approach chart and that superimposed little green airplane. Seconds later we are spit out of the cloud into the dark, gray late afternoon mist of New Hampshire. For some reason I think to myself that this is the second shortest day of the year when it comes to sunlight. Ahead I can see the dark gray-brown scar of a runway outlined by white snow.

After we touch down and taxi in, I tell Cathy about the compass, the flight director and my decision making. She is quiet. When I call my friend JC that night and tell him the story, he laughs when I tell him, "All I had was the copilot's compass. No HSI, no autopilot, no flight director, no altitude preselect. I mean it was almost needle ball and airspeed."

"Ah, come on," replies the retired 747 captain. "You had three artificial horizons, two altimeters, deicing boots, windshield heat, great avionics and plenty of gas."

"Okay, yeah," I say. "But I had only that one backup compass."

JC's response reminds me why I like aviation so much. "But that's what it's FOR!" he says.

Dick Karl
Dick KarlAuthor
Dick Karl is a cancer surgeon who appreciates the beauty and science involved in both surgery and flying. Dick’s monthly Gear Up celebrates the human side of flying. He writes about his enthusiasm for both the machines and the people who fly and maintain them.

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