Federal Aviation Administration, DOT Section 25.103 spaschal on DSK3GDR082PROD with CFR 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 15,000 20,000 25,000 Vapor pressure e (In. Hg.) 0.403 .354 .311 .272 .238 .207 .1805 .1566 .1356 .1172 .1010 .0463 .01978 .00778 Specific humidity w (Lb. moisture per lb. dry air) Density ratio r/s= 0.0023769 0.00849 .00773 .00703 .00638 .00578 .00523 .00472 .00425 .00382 .00343 .00307 .001710 .000896 .000436 0.99508 .96672 .93895 .91178 .88514 .85910 .83361 .80870 .78434 .76053 .73722 .62868 .53263 .44806 (c) The performance must correspond to the propulsive thrust available under the particular ambient atmospheric conditions, the particular flight condition, and the relative humidity specified in paragraph (b) of this section. The available propulsive thrust must correspond to engine power or thrust, not exceeding the approved power or thrust less - (1) Installation losses; and (2) The power or equivalent thrust absorbed by the accessories and services appropriate to the particular ambient atmospheric conditions and the particular flight condition. (d) Unless otherwise prescribed, the applicant must select the takeoff, en route, approach, and landing configurations for the airplane. (e) The airplane configurations may vary with weight, altitude, and temperature, to the extent they are compatible with the operating procedures required by paragraph (f) of this section. (f) Unless otherwise prescribed, in determining the accelerate-stop distances, takeoff flight paths, takeoff distances, and landing distances, changes in the airplane-s configuration, speed, power, and thrust, must be made in accordance with procedures established by the applicant for operation in service. (g) Procedures for the execution of balked landings and missed approaches associated with the conditions pre- [Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended by Amdt. 25-38, 41 FR 55466, Dec. 20, 1976; Amdt. 25-92, 63 FR 8318, Feb. 18, 1998] Section 25.103 Stall speed. (a) The reference stall speed, VSR, is a calibrated airspeed defined by the applicant. VSR may not be less than a 1-g stall speed. VSR is expressed as: VSR - VCL MAX n ZW where: VCLMAX = Calibrated airspeed obtained when the load factor-corrected lift coefficient n ZW W qS is first a maximum during the maneuver prescribed in paragraph (c) of this section. In addition, when the maneuver is limited by a device that abruptly pushes the nose down at a selected angle of attack (e.g., a stick pusher), VCLMAX may not be less than the speed existing at the instant the device operates; nZW = Load factor normal to the flight path at VCLMAX W = Airplane gross weight; S = Aerodynamic reference wing area; and q = Dynamic pressure. (b) VCLMAX is determined with: (1) Engines idling, or, if that resultant thrust causes an appreciable decrease in stall speed, not more than zero thrust at the stall speed; (2) Propeller pitch controls (if applicable) in the takeoff position; 209 VerDate Sep<11>2014 12:50 Apr 30, 2019 Jkt 247046 PO 00000 Frm 00219 Fmt 8010 Sfmt 8010 Y:\SGML\247046.XXX 247046 ER26NO02.002 Altitude H (ft.) scribed in SectionSection 25.119 and 25.121(d) must be established. (h) The procedures established under paragraphs (f) and (g) of this section must - (1) Be able to be consistently executed in service by crews of average skill; (2) Use methods or devices that are safe and reliable; and (3) Include allowance for any time delays, in the execution of the procedures, that may reasonably be expected in service. (i) The accelerate-stop and landing distances prescribed in SectionSection 25.109 and 25.125, respectively, must be determined with all the airplane wheel brake assemblies at the fully worn limit of their allowable wear range. ER26NO02.001 (2) For reciprocating engine powered airplanes, a relative humidity of 80 percent in a standard atmosphere. Engine power corrections for vapor pressure must be made in accordance with the following table: