‘Basic’ IFR

Boy, it’s been a long time since I’ve done THAT! It feels good to know I still can.

It was cloudy with a little drizzle as we loaded up the rented Cessna Skyhawk for a family trip. Although I was departing from a non-tower airfield with no instrument approach, there was a towered airport less than 10 miles away with a functioning Instrument Landing System (ILS) approach and weather at 700 feet and two miles’ visibility. That’s well above minimums for the approach, and good enough (as well as close enough) that I could accept departing into Instrument Meteorological Conditions (IMC). I carefully reviewed the nearby ILS approach, kept the approach plate on top of the stack-o-charts on my lap, and tuned the back-up radios to the ILS frequencies I’d need if something forced a quick return to the ground — just like I learned in my instrument “basic training.” A flip of the nav radio switch and an 180-degree left turn after takeoff would about put me in line for the ILS to the other airport if an emergency cropped up after takeoff.

My first indication this’d be a challenging flight was the weather briefing.

It was mainly marginal VFR in light rain and layered clouds for the first two-thirds of my trip, from near Chattanooga to Charleston, West Virginia. There were a few pockets of IMC along the route I chose — namely the immediate vicinity of the departure airport and one spot in central Kentucky — that avoided the highest terrain of east Tennessee, eastern Kentucky and southern West Virginia. Once I passed the Hazard VOR, conditions were forecast to gradually improve into the Charleston area. But I could expect to be in IMC for much of the trip, and to fly an instrument approach at my arrival airport.

My second glimpse at challenge was when I lined up on Runway 03 for takeoff.

I set the gyroscopic heading indicator to runway heading, but noticed the magnetic compass was reading 30 degrees off. The mag compass moved freely and looked to be full of fluid, so it passed instrument checks. The compass correction card had been marked in the past, but the markings had long since faded. I left the heading indicator on runway heading for takeoff, noting that I’d have to take this magnetic deviation into account as I reset the gyro-compass in flight.

Insider’s Tip: Electrical fields inside the airplane affect magnetic compass indications — we call the error “deviation.’ Mag compasses are “swung” (the deviation quantified) when the airplane is new, and the results noted on a compass correction card. In most airplanes (because most airplanes are old), a lot of electrical equipment has been removed and added since the compass was swung. All this new equipment can make the compass, and the compass correction card, wildly inaccurate.

Strategy: It’s a good idea to “box the compass” (align it to known headings with the engine and all avionics on, and note the deviations for the cardinal directions and points in between) before taking off. (That’s something I’ll add to my Before Takeoff checklist for flying in unfamiliar airplanes from now on.)

Phase Two — EN ROUTE
Takeoff was smooth. We entered clouds at about 500 feet, and we were still in solid IMC when we leveled off at 7000 feet. Small rain droplets marched up the windscreen and blew past the side windows, but the ride was rock-solid and the outside air temperature was far above freezing. I carefully evaluated the tachometer between scans of the flight instruments, looking for any sign of a drop that might indicate carburetor icing, but there was none.

It was challenging to keep the VOR needle straight, while trying to compensate for the magnetic compass errors. It was easier to simply pick ANY heading that would accomplish my purpose: So what if the heading indicator was off a few degrees (because I had no accurate information with which to set it). The instruments described the situation as if I was crabbing into a strong crosswind. The technique worked, and I tracked straight down the airways.

Meanwhile the normal course changes of the route taught me that the mag compass wasn’t inaccurate on anything but headings from about northeast to southeast. On a northerly heading (using my heading indicator), the compass read north as well. So, I thought, reset the heading indicator when on anything other than an easterly heading and I’m in good shape. This technique worked, and after two hours hand-flying in the clag I was cruising between layers, close enough to receive the Automated Terminal Information Service (ATIS) broadcast from Charleston’s Chuck Yeager airport. The weather was good for an instrument arrival (or a VFR arrival, for that matter) — 1500 overcast, visibility exceeding 10 miles, light winds from the southwest.

“November 73928, cross the Charleston VOR at 5000, after crossing fly heading 060, vectors for the ILS 23 at Yeager.” Before I throttled back for the descent I reached up to reset the heading indicator one last time before starting turns toward the east. Well, you know that little knob you push in to set the heading indicator? You know how you push it in, turn the compass card, and then release the knob and the indicator resumes spinning freely? Well, this airplane’s heading indicator made it through Steps 1 and 2 of this procedure just fine, but when I released the knob… the indicator wouldn’t move at all. The knob sprung back out, but the setting system remained engaged, and the gyro would not turn on its own.

I tried to jiggle it loose a few times, but soon realized I was “partial panel” — the vacuum pump was working fine and the attitude indicator was okay, but I had to rely on the magnetic compass for my heading information. Right… that magnetic compass. The one that I couldn’t trust on easterly headings… the direction we’d need to go before we’d intercept the ILS 23 approach course.

Phase Four — HELP, PLEASE

  • First, I set the number two VOR omnibearing selector on the 060 radial — I could use this to help me fly the assigned heading after crossing the VOR.
  • Then I tried the heading indicator setting knob a couple more times, with no change. A few miles on the 060 radial and Approach Control assigned a northerly heading, which I could easily fly using tried-and-true magnetic compass techniques.
  • The only thing left to do… was to ask for outside help. It went something like this:

Let The Drama Begin
Yeager Approach, Cessna niner-two-eight has a heading indicator failure, request a no-gyro approach.” ‘Roger, maintain present heading for now, expect guidance to the localizer for the ILS 23 at Yeager,” came the smooth reply — I hope *I* sounded that calm. I think I did!

Pretty soon it was “Niner-two-eight, start a left turn.” I rolled smoothly into a standard-rate turn, the mag compass lagging and the heading indicator frozen solid. “Stop turn,” the controller soon added, and the mag compass settled down on a roughly northerly heading — most likely, accurately. “Niner-two-eight, start another left turn. This will be a roughly 180 degree turn, which will put you near the localizer.” I started the descending, left-hand turn, three degrees of turn per second, and was turning roughly southwest as the localizer needle centered. I was about three miles outside the marker, inbound on the approach. I told the controller the same, and he handed me off to the tower. Shortly after intercepting the glideslope and beginning my descent I broke out and could see the runway lights straight ahead of me.

My wife and son never knew there was a problem until I told them in the rental car driving away from the airport.

BOTTOM LINE: This was too easy — but only because I’ve practiced these techniques for years, and because I approach every flight with the level of preparation I learned in my basic training. I don’t write this to show how “good” I am, but to remind you that anyone can do it right — and easily — if they fly the way they were taught. Oh, a handheld GPS would’ve been great, but being able to fly the plane helps, too. Besides, handhelds — being able to fly the plane (provided you stay current) is something you get to keep. Review your own “basic training” so you have your “basic” skills in your bag of tricks should you ever need them.