How to fly the maneuver

A constant-airspeed instrument descent is the mirror task to the climb (B) — same scan, same primary shift, same level-off anticipation discipline, applied to a descending altitude profile. The differences are the power setting (reduced for descent rather than climb), the direction of altitude change, and the trim direction (nose down rather than nose up).

Same physics, opposite direction. The pitch-for-airspeed and primary-supporting model carry over from B without modification. Train on the differences from B; B's pedagogy is the foundation.

Setup

1. Begin from a stable straight-and-level (VIII.A baseline).
2. Note the target altitude (below current) and the target descent airspeed (typically cruise or a published descent speed; some airplanes use a slightly higher speed for descent to increase descent rate).

Establish the descent

1. Reduce power to descent setting (typically 1,800–2,100 RPM in a trainer, or per POH).
2. Pitch down to a descent attitude — typically 2–5° below the level-flight pitch reference on the AI.
3. Trim as the airplane settles into the descent.
4. Verify on the ASI — airspeed should stabilize at the target. If high, pitch up slightly. If low, pitch down.

Scan during the descent

Same primary-supporting matrix as the climb (B), with ASI primary for pitch:

For…	Primary	Supporting
Pitch	ASI	AI, VSI, altimeter
Bank	HI	AI, turn coordinator
Power	MP / RPM	ASI, VSI (descent rate)

The scan cycle: AI → ASI → AI → HI → AI → MP/RPM → AI. Same pattern as the climb (B); the prioritization is identical because the maneuver is the same physics in the opposite direction.

Hold the descent

In a stable, trimmed descent:

• ASI reads target ±5 KIAS.
• HI holds heading ±10°.
• Altimeter shows descending.
• VSI shows descent rate (typically 500–700 fpm in a trainer at typical descent power).

The airplane should be hands-off if trimmed properly. Left-turning tendencies are reduced in descent (lower AoA, lower power), so less rudder is needed than in the climb.

Level off

Same anticipation rule as the climb (B): lead the target altitude by 10% of the descent rate.

• 500 fpm descent → 50 ft lead (begin level-off at target + 50 ft).
• 700 fpm descent → 70 ft lead.

Level-off sequence:

1. Pitch up to level cruise attitude (visual on AI).
2. Add power smoothly to cruise setting as the airplane's vertical momentum bleeds off.
3. Trim for the new straight-and-level condition.
4. Cross-check altitude at target ±100 ft (the ACS tolerance, VIII.C.S2).

A late level-off (below the target) busts the standard; an early level-off (settling above target with cruise power applied) is also a bust.

Common pitfall: insufficient power addition at level-off. Pitching up without adding power lets airspeed bleed below the cruise tolerance during the transition. The technique: pitch and power together at the level-off, then trim. Same chord-of-inputs as the climb (B), in the opposite direction.