In the cheap seats

A lot is made of the transition from conventional instruments to glass, and for good reason. Solid instrument meteorological conditions is not the time to learn how to properly program an approach, insert reroutes, or sequence to the missed approach. These everyday tasks take practice and experience. But one element of the transition that’s relatively seamless is basic attitude flying and the scan. Because, let’s be honest, “scanning” in a glass cockpit is a lot more like looking.

You can rightly infer that the opposite is true and the transition from glass to traditional instruments, or steam gauges, makes basic instrument flying more challenging. A good transition program starts with the assumption that flying glass and steam may be grounded in the same principles, but they are two completely different experiences with different techniques, risks, and skills.

The six basic instruments in a traditional cockpit are the same as those consolidated on a glass display. Other than how they’re arranged on the panel, the biggest difference is in how they gather the data. In a glass cockpit the attitude indicator, heading indicator, and turn coordinator show information derived from a digital source: the attitude and heading reference system. And being digital, it has certain properties that make it behave differently than traditional instruments, especially in unusual situations. Namely, when something goes wrong, the pilot is immediately alerted via a black screen with a large red X on it.

Unfortunately, this is not the case with steam gauges. Because these instruments are powered by mechanical gyros, a system failure won’t be immediately apparent. There’s usually not a cockpit indication of a vacuum pump failure, and although some electrical gyros have indicator lights, they’re not widespread. That means when a vacuum pump or electric gyro fails, the gyros slowly spin down, giving the pilot a progressively less reliable indication. Not to be too macabre, but it’s the difference between being hit by a car and having cancer.

Becoming comfortable with a basic scan of conventional instruments and proficient at partial panel flying will go a long way toward a full transition.Dealing with this reality means never really trusting the attitude indicator and directional gyro. Sure, they are part of the scan, and yes, more often than not they are accurate. But despite their central location in the panel, generations of pilots have been trained to use these instruments sparingly, and to view them suspiciously. That means lots of partial-panel practice, which is as easy as covering the instruments with a sticky note.

Aside from determining your normal scan pattern, being proficient at flying partial panel is probably the most important element of flying a steam-gauge airplane. Thankfully, it’s not particularly difficult. Instead of focusing on the attitude indicator for pitch and bank, and the heading indicator for heading and tracking, you must shift your attention to the supporting characters. In most light aircraft a vacuum pump failure manifests as a failure of the attitude indicator and heading indicator, forcing you to ignore their indications despite their central location in the panel. Using the altimeter as a primary pitch attitude, and the airspeed and vertical speed as support is straightforward. More challenging is bank. The turn coordinator is a good start, but remember that its primary indication is the rate of the turn, so it’s not great at showing the angle of bank. It’s also a bit twitchy, and relying on it to maintain wings level can be difficult. The other option is the compass, and that’s even worse.

Using a compass as a turn and bank indicator, and as a heading reference is probably the most difficult part of partial panel work. A few tips: Be patient and remember that unless it’s a vertical card compass, turns are backwards. This is where situational awareness is key. If you’re instructed to turn to 240, and you’re currently heading 360, it’s significantly easier to think of your position from a bird’s-eye view and know that you must turn left than it is to look at the compass and glean the information from there. Also, the compass is sloppy, and it leads and lags. So be patient while using it for turns. This is a case where using time can be even more effective. Need to go that 60 degrees to a 240-degree heading? A standard rate turn is 3 degrees per second, so turn left for 20 seconds, and verify on the compass only after you’re level and the compass has calmed down.

Becoming comfortable with a basic scan of conventional instruments and proficient at partial panel flying will go a long way toward a full transition. Then it’s a matter of learning a new GPS, or heaven forbid, using VORs.

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