Tiptoeing into IFR

Know your personal minimums

August 1, 2003

You got the instrument rating, but your ticket's essentially dry. Maybe you're like most instrument students: You spent a lot of time under the hood during training, but only an hour or two (at most) in actual instrument conditions.

Or, perhaps it's been a few months since the checkride, but a couple of hesitant forays into the clouds hasn't been enough to boost your skills. As a result, your confidence to fly in actual has crumbled to the point where you're basically an IFR-rated VFR pilot.

Or maybe you've had the rating for a long time, but rust has settled in. Or the new crop of avionics creeping into current panels has lowered your comfort level.

In any case, you need to know how to set some personal minimums.

Fear means you need to know more

Apprehension is understandable as you transition from VFR to IFR — especially on the approach, when you must trust the instruments and your interpretation of them as you edge closer to the ground. And it's not only you: Airline pilots don't just jump into a Category III airplane with their own zero-zero qualifications. They spend time restricted to higher minimums until the passage of hours and checkrides proves their proficiency.

You can prove yourself in a similar fashion by keeping your time in IFR conditions at relatively high altitudes to begin with, and progressing to flights in actual to lower and lower minimums as you gain confidence and experience in the system.

But isn't your instrument ticket proof enough? Perhaps. But each time you flew in actual until you passed the checkride, it was with a CFII or examiner on board, or another pilot. Single-pilot IFR is a completely different experience. According to the AOPA Air Safety Foundation's Single-Pilot IFR Safety Advisor, single-pilot IFR flights generate several times more accidents than those flown with two pilots at the helm. Of course, most general aviation IFR flights are likely flown with one pilot, but exposure alone probably doesn't account for the discrepancy in accident numbers.

Fear is often your gut telling you that you need more information. So how do you manage the risk for each flight so that the experience you gain comes in half-hour sitcoms as opposed to slasher movies? Start by quantifying the level of complexity inherent in each IFR flight you propose and setting your minimums accordingly.

Familiarity

The simplest aircraft can feel complex if you don't have much time in front of its panel. The suitability of a particular airplane for a given flight depends on two things: your recent and total experience in the airplane, and the appropriateness of the equipment on board to your proposed flight.

For argument's sake, consider this situation. You obtained your private certificate in an older Cessna 172N. Then you switched flight schools and proceeded through your instrument training in a Piper Archer. Now there's a new 172S on the line, and it's the only aircraft available for you to rent the weekend that you've promised grandma that you'd come and pick some strawberries at the farm.

You spend 1.2 hours checking out in the airplane, and the instructor puts you through the standard stall series, steep turns, and simulated engine failures. Almost as an afterthought, you shoot the ILS back into your home airport. You do a couple of trips around the pattern, and he deems you're good to go.

Saturday morning dawns with a 1,000-foot overcast at your departure airport and stratus layers covering your route to the farm. Reports at Berryland Municipal are well above the airport's GPS approach minimums and should stay that way all day. Sunday promises clearing skies.

It should be a simple instrument flight, with no convection expected and freezing levels up in the jet routes. But you need to ask yourself a few questions.

Have you shot a nonprecision approach in a 172? How do the configurations and airspeeds compare to those in the Archer? Here you win, as the speeds are similar, and both aircraft have fixed gear, fixed-pitch props, and two-axis autopilots.

How well do your personal techniques, such as your approach and prelanding checklists, work in the 172? You may be busy during these times, and your checklist habits need to serve you rather than smite you. For example, the flap operating range is somewhat different between the aircraft you've flown. You remember from your private training that you can use the first 10 degrees of flaps on a 172N at 110 knots — is this the same for the 172S? As it turns out, yes. You may change how you set your approach speed, but only a little, as you had to slow down below 103 kt in the Archer before setting any flaps.

Have you flown into this airport before? Is the approach familiar? While you've never been there in IFR, you've practiced the approach several times on the flight training device at your flight school.

And the big one: Is the GPS unit in the 172S the same as that in the Archer? If not, are there alternate approaches, and/or alternate airports to which you may default? As it turns out, the 172S has a Bendix/King KLN94 GPS, which you've never used outside direct-to mode; the Archer had a Garmin GNS 430. You decide to ask the instructor if he'd like to come with you. It's well worth his going rate — the strawberries are that good.

Weather

In the previous example, the deal-breaker was your lack of proficiency with a particular GPS. The weather forecast actually sounded well tuned to a new IFR pilot's personal weather minimums. But those minimums are personal, so how can you create your own?

After gathering all the weather information available (within reason — this could take days), you need to assess each phase of the flight.

What are the current conditions at the departure airport? Is the field towered or nontowered, and does the tower have radar? You may want your first solo forays into instrument conditions to occur well above the ground. In fact, you may want conditions that allow for a VFR return to the departure airport in case there's a problem. Alternately, if you're operating from a towered airport, the controller may have the ability to vector you to the airport's preferred approach — an ILS? — instead. As you become more proficient in the environment, your departure minimums can drop to the approach minimums for that airport.

En route, what can you expect? If the trip is a long one, and if you don't have a solid autopilot, you may want to wait for conditions that allow you some time outside of actual. Cloud layer reports are notoriously "flexible," and even pireps reflect conditions that were, rather than conditions that are. For these initial IFR flights, a climb to VFR conditions on top is a nice reward for slogging through some clag.

Also, look at ceilings and visibilities along the route. Diverting can be a juggle for experienced pilots — especially diverting into an airport right at approach minimums. Consider plotting your route to stay over areas where you can pop out at 1,000 feet agl or well above approach minimums, whichever is higher.

If the forecast calls for widespread icing or convection, and you can't stay in VFR conditions within the altitude range of your airplane, your IFR ticket probably won't do you much good. Your plan B should include a rental car and/or a good book by the fire.

What about the approach? Though you flew that partial-panel NDB approach to 400 feet agl just fine on your checkride, stack the deck in your favor when it comes to your personal minimums. Look at the approaches for the destination airport, and for your alternate. If there's a simple precision approach at the destination, with backup approaches and an alternate nearby, add a few hundred feet to the published minimums to set your own limit. If the airport has one nonprecision approach and the closest alternate is 50 nm or more away, consider setting your initial minimums at the minimum vectoring altitude. The MVA provides 1,000 feet of obstacle clearance in nonmountainous areas and 2,000 feet in mountainous areas — and goes as low as 300 feet above the floor of any controlled airspace while keeping you in radar contact. If air traffic control can get you below the clouds at this altitude, you can probably proceed to the field VFR. While the MVA for a given area isn't charted, you can estimate this figure by looking at the obstructions on the approach chart — but know that ATC radar coverage can stop at 2,000 feet agl or higher in some areas.

Other considerations

Because personal minimums are yours alone, any number of factors can weigh into your decision. If your flight takes you into a more congested area than usual, or requires you to fly a complex standard terminal arrival route (STAR), you may up your minimums just for that trip. While you may be flying the STAR in the clouds, by setting the minimums high, odds are that you won't have to fly the approach to published minimums, nor be forced to miss. If the flight has left you fatigued for the approach, those are much better odds to play.

Other considerations include your passenger manifest and the trip expectations. Budget plenty of time into your flight planning and preflight if you have specific reasons to get somewhere. Grandma's always happy to see you, but the berries also make great jam to enjoy year round. So leave yourself an out, and stick to those minimums.


E-mail the author at julie.boatman@aopa.org.


Personal Minimums Checklist

Weather. What is the minimum ceiling and visibility? What is the maximum wind and crosswind component?

Approach. What kinds of approaches make you the most comfortable? What if the precision approach at your destination is out of service? Are you OK with flying the nonprecision approach with the weather as forecast?

Proficiency. How much recent time do you have in the aircraft? How much time in actual in the aircraft?

Aircraft. What equipment does the aircraft have? Autopilot; deicing or anti-icing equipment; weather radar, lightning detection, or datalink weather? How competent are you with these systems?

En route considerations. Are icing or convective conditions forecast? Can you stay VFR or on top in these areas?


Links to additional information about personal minimums and single-pilot IFR may be found on AOPA Online ( www.aopa.org/pilot/links/showlinks.cfm?pubdate=8/1/03). Keyword search: IFR.