Pitch-Power-Performance
Pitch and power give airspeed, vertical speed, altitude, attitude and trends for an explicit aircraft model with stated assumptions.
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Set a pitch attitude and a throttle and watch what the airplane does: the airspeed, the vertical speed, the altitude and their trend. Attitude plus power gives performance: the same attitude flies level at one throttle, climbs with more and descends with less; the same throttle gives a fast descent with the nose low and a slow climb with it high. The readout says where the airplane will settle if you hold what you have set. Raise the nose too far for the throttle and the airspeed falls until the wing reaches its critical angle of attack: the model stops at the stall.
The curves show why. The amber curve is the power needed to fly level at each airspeed; the cyan line is the power this throttle gives (dashed: full throttle). Where cyan is above amber the difference is the climb you can have at that speed; where it is below, you descend. The purple band is below L/D max - the minimum-drag speed, about 74 KIAS here, below which the FAA handbooks place the region of reversed command, where more power is needed to fly slower. The coral band is where THIS model, at this throttle, has no speed stability. With a fixed-pitch propeller the two are not the same speed; both are shown.
Pitch for airspeed, power for altitude - or the reverse? The handbooks give both, each in its place. In level flight the Instrument Flying Handbook makes the altimeter primary for pitch and the airspeed indicator primary for power; in a constant-airspeed climb the airspeed indicator is primary for pitch; the Airplane Flying Handbook calls the adage incomplete - pitch plus power controls the energy state - and says that below L/D max pitch is the more effective control of airspeed and power of the path. Demonstrations runs each statement on the model; Practice targets asks you to fly climbs, descents, level-offs and slow flight within the instrument rating tolerances (airspeed ±10 kt, altitude ±100 ft).
Assumption and limits - an explicit, simplified model of one airplane: the Cessna 172S of its Information Manual (POH/AFM Rev. 5), at 2550 lb, flaps up, in the standard atmosphere, without wind, wings level and coordinated, from sea level to 12,000 ft (the range of the POH tables). A point mass: drag CD = 0.0338 + 0.0517 CL² (fitted to the 37 standard-temperature cells of the POH cruise table with a propeller efficiency of 0.80; within 1.1 kt of every cell), full-throttle thrust 630 lbf − 2.24 lbf per knot of true airspeed times the power lapse 1.132 σ − 0.132 (fitted to the POH climb table and maximum speed; climb rates within 30 fpm), lift-curve slope 0.0865 per degree with CLmax 1.54 from the POH flaps-up stall speed and a critical angle of attack of 16° (a model value), the attitude indicator aligned in level flight at 105 KIAS; below 10 % power a windmilling-propeller drag fitted to the POH glide. The pitch attitude you set is held exactly and reached at 4° per second; the engine follows the throttle in about a second; the VSI lags (2.5 s). Trim only tells you which way you would be pushing. Not modelled: flaps, other weights, temperature and wind, torque and P-factor, control forces, turbulence. Above 12,000 ft the model would extrapolate (its 100 fpm ceiling comes out near 15,600 ft against the POH's 14,000 ft), so altitudes are limited to 12,000 ft. The targets, tolerances and scoring are platform conventions. A teaching model, not a certified simulator: use the POH for the airplane you fly.
Aircraft data: Cessna Model 172S Information Manual 172SIM incorporating the POH/AFM Revision 5 (19 July 2004, P/N 172SPHUS05), serials 172S8001 and on - Figure 5-8 Cruise Performance (drag polar), Figure 5-7 Time, Fuel and Distance to Climb and the maximum speed at sea level of the Performance Specifications (full-throttle thrust of the fixed-pitch propeller; the speeds there are for an airplane with speed fairings, about 2 kt faster), Figure 5-1 Airspeed Calibration (indicated airspeed) extended to the Figure 5-3 stall point, the flaps-up stall speed of p. ii (CLmax), Figure 1-1 (wing area 174 sq ft, span 36 ft 1 in), Figure 3-1 Maximum Glide (68 KIAS, read from the graph as 8.85 to 1, for the windmilling drag), Figure 2-2 (the airspeed indicator's arcs). Checks by routes the fits do not use: the 74 cells of the cruise table at 20 °C below and above standard (rms 0.65 kt); the full-throttle rows of the cruise table against the power lapse (within 2 points); the 75 % cruise specification at 8,500 ft (124 kt); the best-rate and best-angle climb speeds of p. 4-5 (rate at 74 / 72 KIAS within 2 % of the model's best; best angle near 62 KIAS); the best power-off glide speed within 10 % of 68 KIAS.
Flight rules: FAA Airplane Flying Handbook FAA-H-8083-3C chapter 4 "Energy Management" (the throttle as the total energy control, the elevator as the energy distribution control, "pitch plus power controls energy state", the three rules of energy control, the power required and available curves, Figure 4-4) and chapter 5 p. 5-9 (below L/D max, "pitch becomes a more effective control of airspeed ... and power is an effective control of the path"; speed instability); FAA Instrument Flying Handbook FAA-H-8083-15B chapter 4 pp. 4-7 to 4-9 (thrust and power required curves, propeller efficiency 80 to 88 percent, the region of reversed command at speeds slower than the minimum drag point, L/D max, "for most general aviation aircraft, this region is very small and is below normal approach speeds"), chapter 6 p. 6-5 (attitude indicator alignment, pitch corrections) and chapter 7 pp. 7-10 to 7-17 (airspeed changes in level flight, climbs and descents at constant airspeed and constant rate, level-off leads). The FAA texts place the boundary of reversed command at the minimum-drag speed; with constant power the minimum of the power curve is lower (about 50 KIAS here), and at a fixed throttle this model loses its speed stability between the two (at sea level about 60 to 69 KIAS, depending on the throttle). Practice tolerances: Instrument Rating ACS FAA-S-ACS-8C IR.IV.A.S1 (altitude ±100 ft, airspeed ±10 kt).
- Cessna Model 172S Information Manual 172SIM incorporating the Pilot’s Operating Handbook and FAA Approved Airplane Flight Manual, Revision 5 (19 July 2004), P/N 172SPHUS05, serials 172S8001 and on - the explicit aircraft model: Figure 5-8 Cruise Performance (drag polar), Figure 5-7 Time, Fuel and Distance to Climb and the Performance Specifications p. ii (full-throttle thrust, maximum speed, 75 % cruise check), Figure 5-1 Airspeed Calibration, Figure 5-3 and p. ii stall speeds (maximum lift), Figure 1-1 wing area and span, Figure 3-1 Maximum Glide, Figure 2-2 airspeed indicator markings, p. 2-5 engine limits, p. 4-5 climb and approach speeds - aircraft data, Model 172S only
- FAA Airplane Flying Handbook, FAA-H-8083-3C (2021, with its MOSAIC addendum of 20 October 2025), chapter 4 "Energy Management: Mastering Altitude and Airspeed Control" (the throttle and elevator as energy controls, "pitch plus power controls energy state", the three rules of energy control, the power required and available curves, Figure 4-4) and chapter 5 p. 5-9 (flight below L/D max: pitch the more effective control of airspeed, power of the path; speed instability)
- FAA Instrument Flying Handbook, FAA-H-8083-15B (current on faa.gov with its Errata and Addenda A and B, read 17 October 2026), chapter 4 pp. 4-7 to 4-9 (thrust and power required, propeller efficiency 80 to 88 percent, regions of normal and reversed command, speed stability), chapter 6 pp. 6-5 to 6-8 (attitude indicator alignment, pitch and power instruments), chapter 7 pp. 7-10 to 7-17 (airspeed changes in level flight, constant-airspeed and constant-rate climbs and descents, level-off leads)
- FAA Pilot's Handbook of Aeronautical Knowledge, FAA-H-8083-25C (2023), chapter 8 p. 8-7 (the VSI lag of 6 to 9 seconds); U.S. Standard Atmosphere 1976 (density); Gagg-Ferrar power lapse of unsupercharged piston engines (P/P0 = 1.132 sigma - 0.132, a standard engineering model, checked against the POH cruise table)
- Instrument Rating Airman Certification Standards FAA-S-ACS-8C (November 2023) IR.IV.A.S1 (altitude within 100 ft, airspeed within 10 kt) - the practice tolerances
- Model choices of this tool (stated on the page): the point-mass model and its fitted values (drag polar, thrust line, windmilling drag), the model values (propeller efficiency 0.80, critical angle of attack 16 degrees, attitude indicator aligned at 105 KIAS, pitch rate 4 degrees per second, engine 1 s, VSI 2.5 s), the 12,000 ft limit, the demonstrations and their pilot, the targets, capture rule and scoring