Constant Airspeed Descents

The IFH gives a method that works with or without an attitude indicator, which is why it is the one to teach (IFH 7-17):

1. Reduce airspeed to the selected descent airspeed while maintaining straight-and-level flight. Stabilize there first.
2. Reduce power further to a predetermined setting.
3. Simultaneously lower the nose to maintain the constant airspeed as the power comes off.
4. Trim off the control pressures.

Teaching it in this order gives the student one variable at a time: get the speed, then trade the power for a descent. Entering straight from cruise means airspeed, power, and attitude all move at once and the descent arrives at whatever speed it likes.

• Constant airspeed descent — any deviation from the desired airspeed calls for a pitch adjustment; airspeed is the primary pitch reference once stabilized (IFH 7-17).
• Constant rate descent — the entry is the same, but once the VSI stabilizes near the desired rate, the VSI is primary for pitch and the airspeed indicator is primary for power (IFH 7-17).

Pitch and power must be closely coordinated when corrections are made, exactly as in the climb (IFH 7-17). The student sentence: pick what you are protecting — speed or rate — and the other one becomes a power problem.

Start the level-off before reaching the altitude; with too little lead the airplane overshoots unless the technique is rapid (IFH 7-17). Assuming a 500 fpm descent:

• Leveling off at an airspeed higher than descent speed — lead the altitude by 100 to 150 feet. Add power to the level-flight cruise setting at the lead point. Because the nose tends to rise as airspeed increases, hold forward pressure to keep the descent rate until roughly 50 feet above the altitude, then smoothly adjust to the level-flight attitude for the airspeed selected (IFH 7-17–7-18).
• Leveling off at descent airspeed — lead by approximately 50 feet, simultaneously adjusting pitch to the level attitude and adding power to the setting that holds that airspeed (IFH 7-18).

Then trim, and continue the normal straight-and-level cross-check.

Ballooning — allowing the nose to pitch up on the level-off — results from failure to maintain the descending attitude with forward-elevator pressure as power is increased to the cruise setting (IFH 7-19). Power comes in, the nose comes up, the airplane climbs through the altitude.

The correction, said in the airplane: "Power in, forward pressure with it — hold the descent until 50 feet to go, then raise the nose." Make them fly three level-offs in a row from the same rate so the pressure timing becomes a habit rather than a reaction. If they are still fighting it, the underlying cause is usually trim: an airplane trimmed for the descent will climb the moment power is added.

From the IFH list for straight climbs and descents (IFH 7-18–7-19):

• Overcontrolling pitch on entry — the descent picture is unfamiliar, so the inputs are large.
• Failure to vary the rate of cross-check during the power and speed change.
• Failure to trim off pressures, so the student cannot tell an aerodynamic pressure change from their own.
• Failure to cross-check both airspeed and vertical speed before adjusting pitch or power.
• Chasing the VSI rather than cross-checking the other pitch instruments.
• Failure to note the rate of descent to compute the lead — overshooting or undershooting the altitude.
• Ballooning on the level-off.
• Failure to recognize the approaching straight-and-level indications — the cross-check must stay accelerated until the airplane is positively established in level flight (IFH 7-19).

Everything gets closer to the ground while the student's eyes are inside a hood.

• Set and brief an altitude floor before the block begins, and own the descent's bottom yourself. Failure to maintain VFR is explicitly listed as a risk (AI.XI.C.R1) — a descent under the hood is the one basic instrument maneuver that can put you into a cloud layer or below a shelf without anyone noticing.
• Collision hazards (AI.XI.C.R3) — a descending airplane is closing on traffic below, and your student cannot see any of it. You are the safety pilot required by 91.109(c); the vigilance is yours alone.
• Airspeed trend — nose-low plus a distracted student equals accelerating. The number to watch is not the altimeter, it is the airspeed rate of change.
• Cooling and engine care — extended low-power descents per the POH/AFM; carburetor heat where applicable.
• Emergency off-airport landings (AI.XI.C.R1) — if the descent were real, where would you go? A useful debrief question that turns a rote maneuver into judgment.
• Distractions, task prioritization, loss of situational awareness (AI.XI.C.R4) — a descent is where you are most tempted to add a radio call, a checklist, or a "where are we?" question, and where a student most readily drops the altimeter to chase airspeed. Teach aviate, navigate, communicate as the ordering rule and introduce distractions deliberately, one at a time, only after the basic descent is stable. Under the hood the student has no external cue that they are near the floor or drifting toward a shelf — that situational awareness is entirely yours.
• When to seek assistance or declare an emergency (AI.XI.C.R2) — the descent is the maneuver most likely to end in inadvertent IMC or terrain proximity. The trigger to teach: advise ATC and, if necessary, declare an emergency before the situation deteriorates beyond the pilot's ability to recover (IFH 11-7), and treat declaring as the appropriate reaction — ATC gives priority handling and 91.3 lets the PIC deviate as required (AIH 1-20).

This Task exists because of the graveyard spiral — the inadvertent-IMC sequence that kills VFR pilots (IFH 3-6). A pilot in a prolonged coordinated turn loses the sensation of turning; on rolling out they feel a turn in the opposite direction, may return to the original turn, notice the altitude loss, and pull — which tightens the spiral and increases the rate of descent.

Frame the lesson that way in the brief: a controlled, trimmed, constant-airspeed descent on instruments is the antidote to a spiral, and the student is learning to make the airplane descend on purpose, at a chosen speed, on a chosen heading. It is the only version of "going down in cloud" that has a good ending.

Lead the power change. A common power fault is failure to lead the airspeed when making power changes — during a deceleration, especially with gear and flaps out, set the throttle for the slower speed before the airspeed reaches it, or the airplane decelerates through and needs another correction (IFH 7-13).

Two more from the same list you will correct out loud: abrupt use of throttle, and fixation on the airspeed or power instrument during the change, which produces erratic control of both (IFH 7-13). Also brief the configuration limits from the POH/AFM — the IFH's own worked example turns on knowing the maximum gear and flap extension speeds before the deceleration begins (IFH 7-12).

• Transition to the descent pitch attitude and power setting on an assigned heading, with proper cross-check, interpretation, and coordinated control application (AI.XI.C.S1).
• Descend at a constant airspeed to specific altitudes, in straight flight and in turns (S2).
• Level off at the assigned altitude and maintain altitude ±100 feet, heading ±10°, airspeed ±10 knots (S3).
• Analyze and correct common errors (S4).

Remember the Area XI note: the evaluator must select at least one Task from this Area of Operation, so descents may well be paired with unusual attitudes — a descent flown badly is the natural entry to Task XI.E.

Keep the airplane doing one new thing at a time and narrate cause and effect (AIH 9-6):

1. "Assigned: descend to 3,000, heading 090, 90 knots. Read it back."
2. "First I slow to 90 in level flight — power back, hold altitude, trim. Airspeed's stable at 90."
3. "Now power to the descent setting and the nose comes down with it. I'm holding 90 with pitch."
4. "VSI settles around 500 down. Altimeter unwinding steadily. Heading 090 — checking it every third glance."
5. "Trimmed off. My hands are light."
6. "Airspeed is my pitch instrument here. It reads 95 — I raise the nose slightly. Watch it come back."
7. "Passing 3,150 — that's my lead. Power to cruise, and forward pressure with it so we don't balloon."
8. "3,050 — nose to the level picture. Trim. Scan is back to normal rate."

Three things:

• It lags. The pointer indication lags a few seconds behind the actual pressure change, but it is more sensitive than the altimeter and is valuable for alerting the pilot to a trend (IFH 5-8). Teach trend first, rate second.
• It can be out of calibration. An improperly set VSI may indicate a descent of 200 fpm when the airplane is in level flight; the IFH's fix is to use that indication as the zero position — know the ground reading and interpret every rate against it (IFH 7-5).
• It is a target, not a leash. When returning to an altitude, the VSI becomes the primary pitch instrument, and the rule of thumb is a rate of about double the altitude error — 100 feet low means about 200 fpm back up, and more than 200 fpm off the desired rate of return is overcontrolling (IFH 7-5).

A student who has been told "don't chase the VSI" and nothing else will simply stop looking at it. Give them the rule that makes it usable.

Build it as a known-to-unknown extension once straight descents are solid. The IFH's point is that knowledge of the power settings and trim changes associated with different combinations of airspeed, gear, and flap configurations reduces cross-check and interpretation problems (IFH 7-11).

The instructional value is not the checklist — it is that the student sees the pitch attitude for level flight change with each configuration, which is the whole argument for why attitude alone is never the answer.