Appendix G
TABLE G-1. PART 23 SUBPART B TESTS FOR SECTION 23.1419 AT AMENDMENT 23-43 (Continued)
Regulation 14 CFR Section
Guidance Climb: all engine operating
23.65 Must be shown to be compliant with engine power losses associated with operating ice protection equipment that are not prohibited for takeoff. Climb performance losses due to ice accretion are normally not appropriate below 400 feet since the airplane should not depart with ice on the airplane. However, if ice protection system operation is prohibited for takeoff or the AFM does not specifically prohibit takeoff with frost on the wing and control surfaces, effect of ice accretions must be considered if:
a. the stall speed with “takeoff” ice at maximum takeoff weight with takeoff flaps, gear retracted exceeds that in non-icing conditions by more than the greater of three KCAS or three percent VS1, and
b. for airplanes in which 23.65(a) is applicable, the degradation of the gradient of climb determined in accordance with § 23.65(a)) with “takeoff” ice is greater than 1.6 percent, and
c. for airplanes in which 23.65(b) is applicable, the degradation of the gradient of climb determined in accordance with § 23.65(b) with “takeoff” ice is greater than 0.8 percent.
*Takeoff climb: one engine inoperative
23.66 If applicable must be compliant.
Climb: one engine inoperative
23.67 The effect of operating ice protection systems on engine performance must be accounted for. The effect of ice accretion on climb performance (lift, drag and climb speed) must be accounted for if:
a. The stall speed with “takeoff” ice at maximum takeoff weight with takeoff flaps, gear retracted exceeds that in non-icing conditions by more than the greater of three KCAS or three percent VS1; and
* Italicized regulations indicate tests not typically accomplished for 23.1419 at am endment 23-14.
G-3
Appendix G
TABLE G-1. PART 23 SUBPART B TESTS FOR SECTION 23.1419 AT AMENDMENT 23-43 (Continued)
Regulation 14 CFR Section
Guidance Climb: one engine inoperative (Cont'd)
23.67 (Cont'd)
b. If commuter category, the degradation of the gradient of climb determined in accordance with § 23.67(c)(2) is greater than onehalf of the applicable actual-to-net takeoff path gradient reduction defined in § 25.61(b), and
c. If multi-engine normal, utility or acrobatic category, the degradation of the gradient of climb determined in accordance with § 23.67(a) or (b) is greater than 0.3 percent.
For paragraphs (b)(1), (c)(1), and (c)(2), “takeoff” ice applies, and for paragraph (c)(3) “Final Takeoff” ice applies, rather than critical ice accretions.
Enroute climb/descent
23.69 Must be accomplished with “Enroute” ice if the enroute climb speed selected in icing is more than the non-icing speed by the greatest of three KCAS or three percent VS1.
Glide: single engines airplanes
23.71 If applicable and if ice protection systems become inoperative with engine out, the best glide speed in icing must be determined if different from the non-icing speed by more than three KCAS. May be determined analytically.
Reference landing approach speed
23.73 Must be based on stall speed with critical ice accretion if that speed exceeds VREF in non-icing conditions by more than five percent or 5 knots, whichever is lower. The VMC determined for non-icing conditions may be used if the vertical tail does not have ice accretion in normal system operation.
Landing distance
23.75 Must be determined with critical ice accretion if VREF in icing conditions is greater than VREF in non-icing conditions by more than five percent or five knots, whichever is lower. The effect of landing speed increase on the landing distance may be determined by analysis.
Balked landing
23.77 Must be compliant with critical ice accretions and all ice protection systems operational at an ambient temperature of 41 degrees F.
G-4
Appendix G
TABLE G-1. PART 23 SUBPART B TESTS FOR SECTION 23.1419 AT AMENDMENT 23-43 (Continued)
Regulation 14 CFR Section
Guidance General (control)
23.141 Only critical loadings as determined during the non-contaminated airplane tests and altitudes below 26,000 feet are required.
23.143 If the non-icing VMC is used for takeoff speeds, it must be shown that the airplane is safely controllable and maneuverable at the minimum V2 for takeoff with the critical engine inoperative and with “takeoff” ice accretion.
If the non-icing VMC is used for VREF, it must be shown that the airplane is safely controllable and maneuverable during a go-around starting at the minimum VREF with the critical engine inoperative and with critical ice accretion.
Susceptibility to ICTS should be evaluated as discussed in paragraph
12.e. of this AC.
Susceptibility to aileron control anomalies in SLD conditions as discussed in paragraph 12.h. of this AC should be addressed.
Longitudinal control
23.145 The tests in paragraphs (a) and (b)(1) and (b)(2) must be accomplished.
For the other tests, the results from the non-contaminated airplane tests should be reviewed to determine whether there are any cases where there was marginal compliance. If so, or if qualitative evaluations with ice accretions show control anomalies, these cases should be repeated with ice. Controllability may be degraded from the non-iced airplane but must still be compliant. Analysis, the results of the non-icing tests to show compliance to § 23.145(e), and the results of controllability tests with ice accretions may be used to show compliance to § 23.145(e).
Directional and lateral control
23.147 Critical configuration(s) determined from the non-contaminated airplane tests must be evaluated. Analysis, the results of the non-icing tests to show compliance to § 23.147(c), and the results of controllability tests with ice accretions may be used to show compliance to § 23.147(c).
G-5
Appendix G
TABLE G-1. PART 23 SUBPART B TESTS FOR SECTION 23.1419 AT AMENDMENT 23-43 (Continued)
Regulation 14 CFR Section
Guidance Minimum control speed
23.149 If the vertical tail is unprotected or has intercycle/residual/runback ice during ice protection system normal operation, VMC speeds with critical ice must be evaluated to determine if the proposed VREF speed in icing complies with § 23.73. Static VMC tests may be used.
Acrobatic maneuvers
23.151 Not applicable for icing certification.
Control during landings
23.153 Must be shown to be compliant.
Elevator control force in maneuvers
23.155 Critical configuration(s) determined from the non-contaminated airplane tests must be evaluated.
Rate of roll 23.157 Airplane must comply with “takeoff” ice accretions for paragraph (a) and critical ice accretions for paragraph (b). Controllability may be degraded from the non-iced airplane but must still be compliant.
Trim 23.161 The results from the non-contaminated airplane tests should be reviewed to determine whether there are any cases where there was marginal compliance. If so, or if qualitative evaluations with ice accretions show any control anomalies, these cases should be repeated with ice. Otherwise, no dedicated tests with ice accretions required, qualitative evaluations can be accomplished concurrently with other tests.
General (stability)
23.171 Must be shown to be compliant.
Static longitudinal stability
23.173 Stability may be degraded from the non-iced airplane but must still be compliant.
Demonstration of static longitudinal stability
23.175 Critical configuration(s) determined from the non-contaminated airplane tests must be evaluated.
G-6
Appendix G
TABLE G-1. PART 23 SUBPART B TESTS FOR SECTION 23.1419 AT AMENDMENT 23-43 (Continued)
Regulation 14 CFR Section
Guidance Static directional and lateral stability
23.177 Must evaluate steady heading sideslips in accordance with paragraph
(d). The results from the non-contaminated airplane tests to show compliance with paragraphs (a) and (b) should be reviewed to determine whether there are any cases where there was marginal compliance. If so, these cases should be repeated with ice. Stability may be degraded from the non-iced airplane but must still be compliant.
Dynamic stability
23.181 Critical configuration(s) determined from the non-contaminated airplane tests must be evaluated.
Wings level stall
23.201 As a minimum wings level stalls with cruise, approach and landing flaps, power off and on, should be evaluated. Roll may slightly exceed 15 degrees if characteristics qualitatively determined to be safe. Stall characteristics should also be evaluated when the airplane is stalled with the autopilot engaged, unless the design of the autopilot precludes its ability to operate beyond stall warning. For these designs the controllability at stall warning should be evaluated.
Turning flight and accelerated turning stalls
23.203 Turning stalls should be evaluated. Accelerated turning stalls not required unless tests with no ice show marginal compliance. Stall characteristics should also be evaluated when the airplane is stalled with the autopilot engaged, unless the design of the autopilot precludes its ability to operate beyond stall warning. For these designs the controllability at stall warning should be evaluated.
Stall warning 23.207
(a)-(c) Should be evaluated concurrently with stall speed and stall characteristics tests. The type of stall warning and the stall warning margin with ice accretions should be the same as with the noncontaminated airplane. Biasing of the stall warning system in icing may be required to achieve acceptable margins to stall. The method of biasing should be evaluated. Adequacy of stall warning when airplane is decelerated with autopilot engaged should be evaluated.
G-7
Appendix G
TABLE G-1. PART 23 SUBPART B TESTS FOR SECTION 23.1419 AT AMENDMENT 23-43 (Continued)
Regulation 14 CFR Section
Guidance Maneuver margin
23.207
(d) 40-degree bank level altitude turns and 30 degree/30 degrees bank-tobank rolls at the flight conditions specified in the regulation should be accomplished to demonstrate the airplane is free of buffet and stall warning with critical ice accretions. All takeoff and approach flap settings should be evaluated. For one-engine inoperative evaluations, only a 30-degree turn is necessary, and the appropriate thrust may be simulated with all engines operating at a reduced power/thrust.
Accelerated stall warning margin
23.207
(e) Not required unless tests with no ice show marginal compliance.
Spinning 23.221 Not required.
Longitudinal stability and control
23.231 Must be shown to be compliant.
Directional stability and control
23.233 Must be shown to be compliant. The results of the steady heading sideslip tests with critical ice may be used to establish the safe cross wind component. If the flight test data show that the maximum sideslip angle demonstrated is similar to that demonstrated with the non-contaminated airplane, and the flight characteristics (e.g., control forces and deflections, bank angle) are similar, then the noncontaminated airplane crosswind component is considered valid.
If the results of the comparison discussed above are not clearly similar, and in the absence of a more rational analysis, a conservative analysis based on the results of the steady heading sideslip tests may be used to establish the safe crosswind component. The crosswind value may be estimated from:
VCW = VREF * sin (sideslip angle) /1.5 where:
VCW is the crosswind component,
VREF is the landing reference speed appropriate to a minimum landing weight, and sideslip angle is that demonstrated at VREF
G-8
Appendix G
TABLE G-1. PART 23 SUBPART B TESTS FOR SECTION 23.1419 AT AMENDMENT 23-43 (Continued)
Regulation 14 CFR Section
Guidance Operation on unpaved surfaces
23.235 Not applicable for icing certification.
Operation on water
23.237 Not applicable for icing certification.
Spray characteristics
23.239 Not applicable for icing certification.
Vibration and buffet
23.251 The non-icing tests should be accomplished with the ice protection systems installed.
Should be qualitatively evaluated in conjunction with other dry air ice shape flight tests up to the lower of:
250 KCAS
VMO/MMO/VNE A speed at which it is demonstrated that the airframe will be free of ice accretion.
Vibration due to propeller icing/de-icing should be evaluated during the natural icing testing.
High speed characteristics
23.253 If applicable, compliance should be shown with airframe ice protection systems installed. Not required with ice accretions.
G-9 and G-10
Appendix H
APPENDIX H. AFM LIMITATIONS AND NORMAL PROCEDURES SECTIONS
1. LIMITATI ONS SECTION. The following text and warning information should be inserted in the limitations section of the AFM:
“a. Flight in meteorological conditions described as freezing rain or freezing drizzle, as determined by the following visual cues, is prohibited:
(1) Unusually extensive ice accreted on the airframe in areas not normally observed to collect ice.
(2) Accumulation of ice on the upper surface (for low-wing airplanes) or lower surface (for high-wing airplanes) of the wing aft of the protected area.
(3) Accumulation of ice on the propeller spinner farther back than normally observed.
If the airplane encounters conditions that are determined to contain freezing rain or freezing drizzle, the pilot must immediately exit the freezing rain or freezing drizzle conditions by changing altitude or course.
NOTE 7
The prohibition on flight in freezing rain or freezing drizzle is not intended to prohibit purely inadvertent encounters with the specified meteorological conditions; however, pilots should make all reasonable efforts to avoid such encounters and must immediately exit the conditions if they are encountered.
b. Use of the autopilot is prohibited when any ice is observed forming aft of the protected surfaces of the wing, or when unusual lateral trim requirements or autopilot trim warnings are encountered.
NOTE 8
The autopilot may mask tactile cues that indicate adverse changes in handling characteristics; therefore, the pilot should consider not using the autopilot when any ice is visible on the airplane.
c. All wing ice inspection lights must be operable prior to flight into known or forecast icing at night.
NOTE 9
This supersedes any relief provided by the Master Minimum Equipment List (MMEL).”
H-1
Appendix H
2. NORMAL PROCEDURES SECTION. The following text and warning information should be inserted in the normal procedures section of the AFM:
WARNING
• If ice is observed forming aft of the protected surfaces of the wing or if unusual lateral trim requirements or autopilot trim warnings are encountered, accomplish the following:
• If the flaps are extended, do not retract them until the airframe is clear of ice.
• The flight crew should reduce the angle-of-attack by increasing speed as much as the airplane configuration and weather allow, without exceeding design maneuvering speed.
• If the autopilot is engaged, hold the control wheel firmly and disengage the autopilot. Do not re-engage the autopilot until the airframe is clear of ice.
• Exit the icing area immediately by changing altitude or course; and
• Report these weather conditions to air traffic control.
CAUTION
Flight in freezing rain, freezing drizzle, or mixed icing conditions (supercooled liquid water and ice crystals) may result in hazardous ice build-up on protected surfaces exceeding the capability of the ice protection system, or may result in ice forming aft of the protected surfaces. This ice may not be shed using the ice protection systems, and it may seriously degrade the performance and controllability of the airplane.
a. The following shall be used to identify freezing rain/freezing drizzle icing conditions:
(1) Unusually extensive ice accreted on the airframe in areas not normally observed to collect ice.
(2) Accumulation of ice on the upper surface or lower surface of the wing aft of the protected area.
(3) Accumulation of ice on the propeller spinner farther back than normally observed.
b. The following may be used to identify possible freezing rain/freezing drizzle conditions:
H-2
Appendix H
(1) Visible rain at temperatures below plus five degrees C outside air temperature (OAT).
(2) Droplets that splash or splatter on impact at temperatures below plus five degrees C OAT.
(3) Performance losses larger than normally encountered in icing conditions. It is possible to experience severe ice accretions not visible to the flight crew, such as wing lower surface accretion on a low wing airplane or propeller blade accretion.
c. Procedures for Exiting the Freezing Rain/Freezing Drizzle Environment. These procedures are applicable to all flight phases from takeoff to landing. Monitor the outside air temperature. While ice may form in freezing drizzle or freezing rain at temperatures as cold as minus 18 degrees C, increased vigilance is warranted at temperatures around freezing with visible moisture present. If the visual cues specified in the AFM for identifying possible freezing rain or freezing drizzle conditions are observed, accomplish the following:
(1) Exit the freezing rain or freezing drizzle icing conditions immediately to avoid extended exposure to flight conditions outside of those for which the airplane has been certificated for operation. Asking for priority to leave the area is fully justified under these conditions.
(2) Avoid abrupt and excessive maneuvering that may exacerbate control difficulties.
(3) Do not engage the autopilot. The autopilot may mask unusual control system forces
(4) If the autopilot is engaged, hold the control wheel firmly and disengage the autopilot.
(5) If an unusual roll response or uncommanded control movement is observed, reduce the angle-of-attack by increasing airspeed or rolling wings level (if in a turn), and apply additional power, if needed.
(6) Avoid extending flaps during extended operation in icing conditions. Operation with flaps extended can result in a reduced wing angle-of-attack, with ice forming on the upper surface further aft on the wing than normal, possibly aft of the protected area.
(7) If the flaps are extended, do not retract them until the airframe is clear of ice.
(8) Report these weather conditions to ATC.
NOTE 10
An alternate means of providing this information in the AFM may be approved by the certifying agency.
H-3 and H-4