Common errors

Constant-airspeed descent errors mirror the climb's (B) error families: primary-shift errors, level-off precision errors, and scan or coordination errors. The added descent-specific concern is altitude awareness — descending past the target has more consequences than overshooting a climb. The six below cover the common faults.

1. Treating altimeter as primary for pitch in the descent

What it looks like: the pilot watches the altimeter unwind and adjusts pitch to "manage the descent rate." Airspeed drifts because the ASI isn't being primary-scanned.

Why: same as the climb (B, ERR #1) — the straight-and-level habit of altimeter-primary carries over.

Fix: ASI is primary for pitch in any constant-airspeed regime, climb or descent. The altimeter is a trend instrument; the ASI is the feedback.

2. Late level-off (through the target)

What it looks like: the pilot waits for the altimeter to read target before starting the level-off. The airplane continues descending past the target by 50–150 ft before the new straight-and-level condition takes effect.

Why: reacting to the altimeter instead of anticipating with the 10% rule. In descent, this is more consequential than in climb because terrain or airspace floors may be just below.

Fix: lead by 10% of the descent rate. At 700 fpm, start the level-off 70 ft above the target. The airplane will arrive at the target as the new straight-and-level stabilizes.

3. Insufficient power addition at level-off

What it looks like: the pilot pitches up to level the airplane but doesn't add power. Airspeed bleeds below the cruise tolerance during the transition.

Why: focused on pitch and altitude; power is forgotten.

Fix: pitch and power together at the level-off. Same chord of inputs as the climb (B, HOW); inverted direction. Don't pitch without adding power.

4. Continuing past the target altitude

What it looks like: the airplane is past the target altitude and continuing to descend; the pilot is still scanning when they should be leveling.

Why: scan breakdown — the pilot was focused on heading or airspeed during the critical level-off moment and missed the altitude milestone.

Fix: the altimeter check is the most-critical scan item during the level-off setup. As the airplane approaches the lead distance above target, the altimeter becomes the most-checked primary. Once leveled, the cycle returns to normal.

5. Right heading drift in the descent

What it looks like: during the descent, the airplane drifts right of heading by 10–15°.

Why: the pilot carried over the climb's right-rudder pressure (B) without adjusting for the descent's reduced left-turning tendency. The result is too much right rudder, which yaws right.

Fix: reduce rudder pressure when transitioning from climb to descent. The descent regime needs less right rudder; let the airplane settle and use the HI as the diagnostic.

6. Trim not adjusted for descent attitude

What it looks like: the pilot pitches forward into a descent attitude but doesn't re-trim. The yoke requires forward pressure to maintain the descent; if released, the airplane returns to level flight.

Why: habit-overrides — the climb's trim was nose-up; the descent needs the opposite; the pilot didn't make the change.

Fix: trim is the second step of every configuration change. After establishing the descent pitch, trim to hands-off. If forward pressure is required to hold the descent, more nose-down trim.

How errors compound. Late level-off (#2) combined with altitude-awareness failure (#4) is the descent-specific risk pattern — and the one that produces "controlled flight into terrain" type incidents in instrument flight. The discipline that prevents the chain: the altimeter is the most-critical primary during the level-off approach window, regardless of the standard "ASI primary for pitch" rule. The general principle is scan priority shifts to the parameter most likely to bust within the next few seconds. In descent's level-off, that's the altimeter.