3. § 23.235 Operation on Unpaved Surfaces.
a. Explanation. This requirement states that the airplane landing gear shock absorbing mechanism must function as intended throughout the expected operating envelope of the airplane.
b. Procedures. During the development and certification flight testing, the airplane should be operated on a variety of runways including those considered to be the worst (in terms of roughness) appropriate to the type of airplane. There should be no evidence of damage to the airplane during these operations.
4. § 23.237 Operation on Water. Allowable water surface conditions should be established during the certification flight testing, depending on the type of aircraft, to ensure safe operation and attainment of the published takeoff and landing performance.
5. § 23.239 Spray Characteristics.
a. Explanation. This rule is intended to ensure that any spray produced during water operation neither excessively interferes with the pilot's visibility nor damages, beyond "normal wear-and-tear," the airplane itself.
b. Procedures.
(1) Taxi, takeoff, and landing. Taxi, takeoff, and landing operations should be conducted throughout the approved loading envelope. Spray patterns should be specifically noted with respect to visibility and their contact areas on the airplane. These areas should be monitored to assure compliance with the rule.
(2) Reversing propellers. Airplanes with reversing propellers should be demonstrated to comply at the highest reverse power expected to be applicable to the airplane operation.
Section 10. Miscellaneous Flight Requirements
1. § 23.251 Vibration and Buffering.
a. Explanation.
(1) Flutter. The test required under this section should not be confused with flutter tests, which are required under § 23.629. Test are typically considered elevated risk and should be carefully planned and conducted.
(2) Test Speeds. Prior to the test, the pilot shou ld coordinate with the airframe engineer to determine that the flutter requirements of § 23.629 have been satisfied and to determine the most critical weight and c.g. for the test. The flight test engineer and pilot should obtain from the airframe engineer the dive equivalent airspeed and Mach number to which the test should be conducted. In the absence of a well-calibrated Mach meter, knowing the Mach number and equivalent airspeed, a schedule of pressure altitude and indicated airspeed should be developed for the test.
(3) Airspeed Determination. Another major considera tion is CAS determination during the test. In this regard, a calibrated, sensitive airspeed indicator should be installed to provide accurate readability. Careful study of the airplane's airspeed position error/correction curve is required with respect to the characteristics of the slope at the high-speed end and how the airspeed calibration was conducted. This is necessary to determine the adequacy of the airspeed position error curve for extrapolating to VD/MD. Refer to appendix 7, figure 5, for compressibility corrections. An expanded Mach number calibrated-airspeed graph may be found in the Air Force "Flight Test Engineering Handbook" (refer to appendix 2, paragraph f(2) of this AC).
(4) Springs. If the airplane incorporates spring devices in any of the control systems, the test should be conducted with the spring devices connected and disconnected. Alternately, if satisfactory spring reliability is shown in accordance with § 23.687, tests with springs disconnected are not required.
(5) Mach Limits. For those airplanes that are ob serving Mach limits, the tests should be repeated at MD speed. Careful selection of the test altitude for both MD and VD tests will help cut down on the number of repeat runs necessary to determine compliance. Attempting to combine the tests at the knee of the airspeed/Mach curve should be approached cautiously since it can result in overshooting the desired speed.
b. Procedures.
(1) Configuration. In the clean configur ation at the gross weight, most critical c.g.
(probably most aft) and the altitude selected for the start of the test, the airplane should be trimmed in level flight at maximum continuous power. Speed is gained in a dive in gradual increments until VD/MD, or VDF/MDF for turbojets, is attained. The airplane should be trimmed, if possible, throughout the maneuver. Remain at the maximum speed only long enough to determine the absence of excessive buffet, vibration, or controllability problems.
(2) Flaps extended. With flaps extended and the airplane trimmed in level flight at a speed below VFE, stabilize at VFE in a shallow dive and make the same determinations as listed in (1) above.
2. § 23.253 High Speed Characteristics.
a. Explanation.
(1) Related Sections. The design dive speeds are established under the provisions of § 23.335, with the airspeed limits established under the provisions of § 23.1505. There is distinction made in both regulatory sections for airplanes that accelerate quickly when upset.
The high-speed characteristics, in any case, should be evaluated by flight demonstration. Section
23.1303(e) gives the requirements for a speed-warning device.
(2) Dynamic Pressure and Mach. In general, the same maneuvers should be accomplished in both the dynamic pressure (q) and Mach (M) critical ranges. All maneuvers in either range should be accomplished at thrust and trim points appropriate for the specific range being evaluated. Some maneuvers in the Mach ra nge may be more critical for some airplanes due to drag rise characteristics.
(3) Flight Crew Duties. The airplane's handling char acteristics in the high-speed range should be investigated in terms of anticipated action on the part of the flight crew during normal and emergency conditions. Consideration should be given to their duties, which not only 107
involve piloting the airplane, but also the operational and navigational duties having to do with traffic control and record keeping necessary to the progress of safe flight.
(4) Upset Axes. The upset criteria of § 23.335(b)(4)(i) is predicated on an upset in pitch while operational evaluation of upsets expected to occur in service should cover pitch, roll, yaw, and critical combinations of multi-axis upsets.
(5) Factors. The following factors are involved in the flight test investigation of high-speed characteristics:
(i) Effectiveness of longitudinal control at VMO/MMO and up to the demonstrated VD/MD speed;
(ii) Effect of any reasonably probable mis-trim on upset and recovery;
(iii) Dynamic and static stability;
(iv) The speed increase that may result from likely mass movement that occurs when trimmed at any cruise speed to VMO/MMO;
(v) Trim changes resulting from compressibility effects. Evaluation should cover Mach tuck, control reversal, or other phenomena associated with high speed;
(vi) Characteristics exhibited during recovery from inadvertent speed increase;
(vii) Upsets due to turbulence (vertical, horizontal, and combination gusts);
(viii) Effective and unmistakable aural speed warning at VMO plus six knots, or MMO plus 0.0lM;
(ix) Speed control during application of devices (power, speed brakes, high-speed spoilers, and so forth); and
(x) Characteristics and controllability during and after failure or malfunction of any stability augmentation system.
(6) Type of Warning. Operational experi ence has revealed that an important and effective deterrent to inadvertent overspeeding is an aural warning device, which is distinctively different from aural warning used for other purposes. Aerodynamic buffeting is influenced by, and is similar to, the effects of turbulence at high speed and is not normally considered to be suitable as an overspeed warning.
(7) Speed Margins. Once it is established whether the airplane limits will be V NE or VMO, appropriate speed margins and markings may be evaluated. The factors outlined in § 23.335 have been considered in establishing minimum speed margins during past type certification programs for the appropriate speeds. The factors to be considered are the following:
(i) Increment allowance for gusts (0.02M);
(ii) Increment allowance for penetration of jet stream or cold front (0.0l5M);
(iii) Increment allowance for production differences of airspeed systems
(0.005M), unless larger tolerances or errors are found to exist;
(iv) Increment allowance for production tolerances of overspeed warning errors
(0.0lM), unless larger tolerances or errors are found to exist;
(v) Increment allowance M, due to speed overshoot from MMO, established by upset during flight tests in accordance with § 23.253, should be added to the values for production differences and equipment tolerances. The minimum acceptable combined value should not be less than that required by § 23.335(b)(4) between MMO and MD. The value of MMO should not be greater than the lowest value obtained from each of the following equations and from § 23.1505:
MMO = MD - M - .005M - .01M or MMO = MD - the Mach increment required by § 23.335(b)(4)
(vi) Altitudes where dynamic pressure (q) is limiting, the allowances of items (i) and (ii) are applicable, and the Mach increment is converted to the units used for the limits;
(vii) At altitudes where q is limiting, the increment allowance for production differences of airspeed systems and production tolerances of overspeed warning errors are three and six knots, respectively, unless larger differences or errors are found to exist; and
(viii) Increment allowance V, due to speed overshoot from VMO established by upset during flight tests in accordance with § 23.253, should be added to the values for production differences and equipment tolerances. The value of VMO should not be greater than the lowest obtained from the following:
VMO = VD - V - 3 knots (prod. diff.) - 6 knots (equip. tol.)
or for VNO airplanes:
VNO = V D - V - 3 knots (prod. diff.) - 6 knots (equip. tol.)
b. Procedures. Using the VMO/VNO, MMO, or the associated design or demonstrated dive speeds determined in accordance with §§ 23.251, 23.335, and 23.1505, the airplane should be shown to comply with the high speed characteristics of § 23.253 and that adequate speed margins exist. The airplane characteristics should be investigated at any speed up to and including VNO, VMO/MMO or VD/MD, as required by § 23.253. The recovery procedures used should be those selected by the applicant, except that the normal acceleration during recovery should not exceed l.5g (total).
(1) C.G. Shift. The airplane should be upset by the c.g shift corresponding to the forward movement of a representative number of passengers depending upon the airplane interior configuration. The airp lane should be allowed to accelerate for three seconds after the calibrated VMO/MMO (not overspeed warning) occurs before recovery is initiated. Note the maximum airspeed. Do not exceed VD /MD.
(2) Inadvertent Control Movement. Simulate an evasive control application when trimmed at VMO/MMO by applying sufficient forward force to the elevator control to produce
0.5g (total) for a period of five seconds, after which recovery should be effected at not more than
l.5g (total). Care should be taken not to exceed VD /MD during the entry maneuver.
(3) Gust Upset.
(i) Lateral Upset. With the airplane trimmed at any likely cruise speed up to VMO/MMO in wings level flight, perform a lateral upset to the same angle as that for autopilot approval, or to a maximum bank angle appropriate to the airplane, whichever is critical.
Operationally, it has been determined that the maximum bank angle appropriate for the airplane should not be less than 45 degrees, need not be greater than 60 degrees, and should depend upon airplane stability and inertia characteristics. The lower and upper limits should be used for airplanes with low and high maneuverability, respectively. Following this, with the controls free, the evaluation should be conducted for a minimum of three seconds after the calibrated value of VMO/MMO (not overspeed warning) or ten seconds, whichever occurs first.
(ii) Longitudinal Upset. Perform a longitudinal upset as follows:
(A) Trim at VMO/MMO using power required for level flight but with not more than maximum continuous power. If the airplane will not reach VMO/MMO at maximum continuous power, push over to VMO/MMO and trim.
(B) If descending to achieve VMO/MMO, return to level flight without changing trim.
(C) Perform a longitudinal upset from normal cruise by displacing the attitude of the airplane in the range between 6-12 degrees, which has been determined from service experience to be an optimum range. The value of displacement should be appropriate to the airplane type and should depend upon airplane stability and inertia characteristics. The lower and upper limits should be used for airplanes with low and high maneuverability, respectively.
(D) The airplane should be permitted to accelerate until three seconds after the calibrated value of VMO/MMO (not overspeed warning).
(iii) Two-Axis Upset. Perform a two-axis upset consisting of a longitudinal upset combined with a lateral upset. Perform a longitudinal upset by displacing the attitude of the airplane as in the previous paragraph, and simultaneously perform lateral upset by rolling the airplane to the 15-25 degree bank angle range, which was determined to be operationally representative. The values of displacement should be appropriate to the airplane type and should depend upon airplane stability and inertia characteristics. The lower and upper limits should be used for airplanes with low and high maneuverability, respectively. The established attitude should be maintained until the overspeed warning occurs. The airplane should be permitted to accelerate until three seconds after the calibrated value of VMO/MMO (not overspeed warning).
(4) Leveling Off From Climb. Perform transition from c limb to level flight without reducing power below the maximum value permitted for climb until the overspeed warning has occurred. Recovery should be accomplished by applying not more than l.5g (total).
(5) Descent From Mach to Airspeed Limit Altitude. A descent should be initiated at MMO and performed at the airspeed schedule defined in MMO until the overspeed warning occurs. The airplane should be permitted to de scend into the airspeed limit altitude where recovery should be accomplished after overspeed warning occurs by applying not more than l.5g (total). The maneuver should be completed without exceeding V D.
Chapter 3. Subpart D--Design and Construction Section 1. General
1. § 23.629 Flutter.
This subject is covered in AC 23.629-1B.
Section 2. Control Systems
1. § 23.671 General.
Reserved.
2. § 23.672 Stability Augmentation and Automatic and Power Operated Systems.
Reserved.
3. § 23.677 Trim Systems.
a. Qualitative Evaluation. Trim should be qualitatively evaluated during all phases of the flight test program. Cockpit control trim devices should be evaluated for smoothness, sense of motion, and ease of operation, accessibility, and visibility of the trim tab indicators (both day and night). Ease in estab lishing and maintaining a trim condition should be evaluated.
b. Electric Trim Background. Electrically-actuated, manually-controlled trim systems have been certificated in several ways, depending on systems design. The simpler systems are tested for failure in flight. More sophisticated systems, which generally incorporate dual-wire, split-actuating switches, may require a dual failure to produce a runaway. Analysis of these systems discloses that one switch could fail closed and remain undetected until a failure occurred in the other switch or circuit to produce a runaway. This is still considered acceptable if the applicant provided a preflight test procedure that will detect such a dormant failure. Service experience dictates that evaluation of fail-safe trim systems by analysis alone is not acceptable and flight testing is required.
c. Explanation.
(1) Fault Analysis. A fault analysis should be evaluated for each trim system.
(2) Single Failure and Back-up System. For a system in which the fault analysis indicates a single failure will cause runaway, flight tests should be conducted. For a system with back-up features, or a redundant system where multiple failures would be required for runaway, the certification team should determine the extent of the flight tests necessary after consideration of the fault analysis and determination of the probability and effect of runaway. In all cases, flight test evaluations should be conducted to determine functional system/airplane compatibility in accordance with § 23.1301.
(3) Failure. For the purpose of a fault analysis, a failure is the first fault obviously detectable by the pilot and should follow probable combinations of undetectable failures assumed as latent failures existing at the occurrence of the detectable failure. When an initial failure also causes other failures, the initial failure and the subsequent failures are considered to constitute a single failure for purposes of fault analysis. Only independent failures may be introduced into the fault analysis to show multiple failure integrity.
(4) Failure Warning. The first indication a pilot has of a trim runaway is a deviation from the intended flight path, abnormal control movements, or a warning from a reliable failure warning system. The following time delays after pilot recognition are considered appropriate:
(i) Takeoff, approach, landing - one second.
(ii) Climb, cruise, descent - three seconds.
(5) Second Set of Controls. If a set of controls and instruments are provided for a second crew member, multi-function systems disconnect or quick-disconnect/interrupt switches, as appropriate, should be provided for both crew members regardless of minimum crew.
d. Definitions.
(1) Disconnect Switch. A switch, which has the pr imary purpose of stopping all movement of the electric trim system, that is located within immediate reach and readily accessible to the pilot. A circuit breaker is not considered to be a disconnect switch.
(2) Quick-Disconnect/Interrupt Switch. A switch or device, which is located on the control wheel on the side opposite the throttles, or on the stick control, that momentarily interrupts all movement of the electric trim system and can be operated without moving the hand from its normal position on the control. The primary purpose of the switch is to stop all movement of the electric trim system.
e. Procedures.
(1) Quick-Disconnect or Interrupt Switch. With a quick-disconnect or interrupt switch located on the pilot’s control wheel or stick, disconnect may be initiated after the delay times given in 23.677c(4).
(2) Disconnect Switch. With a disconnect switch located somewhere on the panel other than the pilot’s control wheel or stick, the time delays given in § 23.677c(4) should be applied prior to corrective action by use of primary controls. In addition to these time delays, an appropriate reaction time to locate the switch and disconnect the systems should be added.
When there are other switches in the immediate area of the disconnect switch, a time increment the same as for the quick disconnect should be added to account for identifying the switch. This effectively doubles the time delay for a cockpit located disconnect switch.
(3) Loads. The loads experienced as a result of the malfunction should normally not exceed an envelope of 0 to +2g. The positive lim it may be increased if analysis has shown that neither the malfunction nor subsequent corrective action would result in a load beyond limit load. In this case, careful c onsideration should be given to the delay time applied, since it may be more difficult for the pilot to reach the disconnect switch.
(4) High Speed Malfunctions. When high speed malfunctions are introduced at V NE or VMO/MMO, whichever is appropriate, the speed excursion, using the primary controls and any speed reduction controls/devices, should not exceed the demonstrated upset speed established under § 23.253 for airplanes with a VMO/MMO speed limitation and a speed midway between VNE and VD for those airplanes certified with a VNE limitation.
(5) Speed Limitations. The use of a reduction of VNE/VMO/MMO in complying with paragraph e(4) of this section is not considered acceptable, unless these new speeds represent limitations for the overall operation of the airplane.
__________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ 11/16/2011 AC 23-8C
(6) Forces. The forces encountered in the te sts should conform to the requirements of § 23.143 for temporary and prolonged application. Also, refer to paragraph 23.143 of this AC.
(i) To allow expansion of the 0 to 2g envelope, the FAA suggests a test procedure that incorporates both control restrained and unrestrained malfunctions. The following test matrix considers the probability of trim runaways, high airframe limit loads, control stick/wheel configuration and absence of an autopilot system. Because rudder trim can be adjusted without the pilot directly in the control loop (that is, feet on the floor), restrained runaways for rudder trim are not considered acceptable. (Refer to table 8 below.)
Table 8 - Trim Systems Requirements Maximum Maximum Force Maximum Axis Time Load(g) Attitude (restrained and Rate of Force (unrestrained) Change unrestrained) Change (unrestrained) (restrained) Pitch recognition structural +/-45 degrees 60 pounds 20 pounds/sec +3 seconds limits NTE
3.5g Roll recognition structural +/-90 degrees 30 pounds 10 pounds/sec +3 seconds limits Yaw recognition structural +/-30 degrees 150 pounds N/A +3 seconds limits (unrestrained only) Note 1: “Restrained” means the pilot is in the control loop (hands on) and “unrestrained” means the pilot is not in the control loop (hands off).
Note 2: Trim systems with a monitor/limiter will be tested at a magnitude just below that required for monitor/limiter trip.
Note 3: NTE is Not to Exceed.
4. § 23.679 Control System Locks.
This subject is covered in AC 23-17.
5. § 23.689 Cable Systems. Section 23.689(f) allows for tab control cables that are not part of the primary control system to be less then 1/8 inch in diameter as long as the airplane is safely controllable with the tabs in the most adverse positions. Flight testing only requires that the tabs be in the most adverse positions associated with the airplane’s operating envelope. This would typically be at the lowest and fastest trimmable operating speeds with the airplane loaded at forward cg. Safely controllable is subjective and has to be determined by an FAA test pilot. If there is disagreement between an applicant and the FAA, a multiple pilot evaluation may be used to make the final compliance determination. Typically, the forces in § 23.143 for “prolonged” use are not used because they are intended for normal operation and are unreasonably low for a failure condition. If the forces are so high that the pilot cannot adequately control the airplane, 113
as determined by an FAA flight test evaluation, then the applicant should consider mitigation strategies and include them in the AFM.
6. § 23.691 Artificial Stall Barrier System.
Reserved.
7. § 23.697 Wing Flap Controls.
Reserved.
8. § 23.699 Wing Flap Position Indicator. Reserved.
9. § 23.701 Flap Interconnection. This subject is covered in AC 23-17.
Section 3. Landing Gear
1. § 23.729 Landing Gear Extension and Retraction System. This subject is covered in AC 23-17.
2. § 23.735 Brakes. Reserved.
Section 4. Personnel and Cargo Accommodations
1. § 23.771 Pilot Compartment.
Reserved.
2. § 23.773 Pilot Compartment View.
a. Pilot Position and View. For all evaluations, the pilot(s) should be seated at the intended design eye level as determined by an installed guide, if established. If an intended design eye level is not provided, the normal seating position should be used. The field of view that should remain clear should include the area specified in § 23.775(e).
b. External View. The external vision should be evaluated in all lighting and environmental conditions (day and night) with the airplane in all attitudes normally encountered.
Attention to windshield distortion or refraction should especially be given to the view toward the approach and runway lights and the runway markings. Since glare and reflection often differ with the sun's inclination, consideration should be given to evaluating the cockpit at midday and in early morning or late afternoon. If the windshield is heated, evaluations should be conducted with heat on and off. Distortion and refract ion should be so low as to prevent any unsafe condition, unusual eye strain or fatigue. "Safe ope ration," as used in § 23.773(a)(1), includes the ability to conduct straight ahead and circling approaches under all approved operating conditions, including operations in high humidity and icing conditions (if appropriate).
(1) Section 23.773(a)(2) requires that windshields be free from glare and reflections that could interfere with the pilot’s vision. Multiple imaging can be a problem with acrylic windshields 0.250 inches or thicker. Appare ntly, this is not a condition caused by any manufacturing operation, but it is caused by the highly polished reflective surface of the new acrylic sheet when viewed at an angle. Tests for reflections can be performed at night using runway and taxiway lights or by using the guidance in SAE AMS-G-25871.
c. Night Approval. If night approval is requested, all lighting, both internal and external, should be evaluated in likely combinations and under expected flight conditions.
Instrument lighting should be evaluated at night under a variety of ambient conditions, including night IFR. Windshield/side wi ndow reflections that distract from traffic avoidance, landing approach and landing are not acceptable. Landing lights, strobes, beacons, and recognition lights should be evaluated to ensure no adverse reflections or direct impingement into the cockpit.
d. Defog/Defrost/Deice. The adequacy of the defog/defrost/deice systems should be evaluated under the following conditions:
(1) Extended cold soak at maximum altitudes and minimum temperatures. The airplane should be exposed to a cold environment appropriate to minimum expected temperatures. The airplane should be also evaluated after remaining outside on a cold night.
(2) Field of view. The airplane should be expos ed to cold temperatures (cold soaked) and then descended into a warmer, moister air mass to assess ability to maintain a clear field of view. To properly evalua te internal fogging, the test airplane should be flown at night at high altitude for at least two hours (or until the windshield temperature stabilizes). Then, using proposed AFM procedures, the airplane should be rapidly descended to an approach and landing in a high humidity area (recommend dewpoint of least 70 °F (21 C)). If manual clearing by the pilot(s) is required, it should be "easily" accomplished by an average pilot. The applicant should provide any special equipment required to accomplish the manual clearing. Repeated immediate clearing after manually wiping the windshield would not seem to fit the "easily cleared" requirements. The "easily cleared" aspects should also be evaluated considering that the fogged windshield could frost under certain conditions. If manual clearing is required, pilot workload should be carefully evaluated if IFR approval is sought.
(3) Evaluation conditions. Evaluations should be conducted in moderate rain, day and night (if approval is sought), takeoffs, landings, and taxi.
e. Two Pilot Airplanes. It is recommended that two pilot airplanes have pilot visibility in accordance with SAE Aerospace Standard AS 580B, "Pilot Visibility from the Flight Deck Design Objectives for Commercial Transport Aircraft."
f. Cockpit Camera. An evaluation and documentation of the cockpit using a binocular camera is highly desirable.
3. § 23.775 Windshields and Windows. For commuter category airplanes, assuming loss of vision through any one panel in front of the pilot(s), either side panels or co-pilot panels, or both, may be used to show that continued safe flight and landing is possible using these panels only while remaining seated at a pilot(s) station. For aircraft to be certified for IFR, the applicant should show that a safe landing can be demonstrated with IFR certified minimum visibility conditions.
4. § 23.777 Cockpit Controls. Reserved.
5. § 23.785 Seats, Berths, Litters, Safe ty Belts and Shoulder Harnesses.
a. Explanation. This subpart requires an approved seat for each occupant.
b. Procedures. Confirm that, when approved production seats are in place, the seats can be easily adjusted and will remain in a locked position.
6. § 23.803 Emergency Evacuation. This subject is covered in AC 20-118A.
7. § 23.807 Emergency Exits. This subject is covered in AC 23-17.
8. § 23.831 Ventilation.
a. Explanation. This subpart requires the carbon monoxide concentration not to exceed one part in 20,000 parts of air, which is 0.005 of one percent or 50 parts-per-million. A sample matrix for CO concentration is given in table 9.
b. Procedures. Test for Carbon Monoxide:
(1) Airplane may be at any convenient weight and c.g. position.
(2) Using a “CO” indicator reading instrument, record the values for the following table:
Table 9 – Sample of Co-Concentration Matrix Climb M.C. Power or Full Throttle Speed VREF Mixture Full Rich Cruise 75 percent M.C.
Power Mixture Glide Engine(s) throttled Speed VREF Flaps up Windows and/or Vents Partly open Closed Partly open Closed Partly open Closed
a. Maximum Reading (Cockpit):
(1) Along Windows and /or Vents
(2) Along Floor
(3) Front of Instrument Panel
(4) Front of Pilots Face
b. Maximum Reading (cabin):
(1) Front
(2) Center
(3) Rear
AUXILIARY
POWER UNIT Installed? No Yes
HEATERS Installed? No Yes OTHERS
c. With Tester Directly in Front of Unit While Unit is Operating 116
Section 5. Pressurization
1. § 23.841 Pressurization Cabins. This subject is covered in AC 23-17.
2. § 23.843 Pressurization Tests. Reserved.