125 established after considering human factors, evacuation demonstrations, and existing airworthiness standards.
Test Procedure Area of opening. The following factors should be considered when measuring or computing the area of opening:
a. Firm protrusions that would hamper egress should be removed from the minimum required exit opening. Examples are seals or escape latches that will not easily compress, move, or fold out of the opening with the motion of a person moving through the opening.
b. When a compressible seal protrudes into an opening, the seal may be in the compressed condition when measuring or computing the opening area.
c. During the comparison test, the emergency ex it opening used as a standard is an opening that will allow passage of a 19 x 26 inch ellipse with a major axis being in a vertical position, a horizontal position, or any other position.
d. The area leading to the opening shou ld be clear and unobstructed. Minor obstructions could be acceptable if there are compensating factors to preserve the effectiveness of the exit. That is, a total effective open area of 388 square inches and the most critical dimension, width or height, not less than 19 inches. For example, soft seatback cushions may constitute minor obstructions: if the cushion can be readily moved away from the exit and the exit can be easily opened, and 2) if the cushion in its normal position does not prevent identification of the exit or obscure the exit marking.
Comparison Test Conditions. The comparison test will determine the difference in mean escape time between either the proposed and standard exit or exits.
a. A mockup of a section of the fuselage may be used. The arrangement of exits, passenger seats, and the step-up and step-down distances from the sill to the wing or step may be simulated. Ramps or stands are allowed to help participants in descending from a wing when over-wing exits are used if the acceptance rate of the ramp or stand is no greater than that of the assist means of the airplane in a crash landing situation. Mats may be used on the floor or ground to protect participants. No other equipment that is not part of the airplanes emergency evacuation equipment may be used to aid the participants in reaching the ground.
b. At the start of each trial, participan ts should be seated as called out in AC 20-118A, “Emergency Evacuation Demonstration.”
c. Participants should not be allowed any “p ractice” runs, but they may be briefed on the purpose of the test to show a rapid emergency evacuation of the airplane.
126 They should not be briefed that the test is to compare exits. An example of an acceptable instruction would be to pass through one foot first, followed by the head and the other foot. The briefing should be the same for each trial.
d. The test should be conducted under dark or simulated dark conditions for both standard and proposed exit configurations for the compliance inspection requirements of AC 20-118A.
e. The participant composition should be as specified in AC 20-118A.
Statistical Design. An acceptable statistical design is as follows:
a. There should be 15 or more participants for each exit configuration to be tested, including the standard configuration.
b. The participants should be assigned to the number of subgroups corresponding to the number of exit configurations to be tested. As noted in paragraph a, each subgroup should have at least 15 people unless the seating configuration is less than 15. In this case the following procedures should be used:
(1) The subgroups should be divided in to sub-subgroups of approximately equivalent size where the sub-subgroup size is equal to or less than the seating capacity of the airplane. The egress time of the sub-subgroups is totaled to constitute the subgroup time.
(2) When a mockup for an airplane is use d, even if the number of passenger seats is less than 15, the total subgroup of 15 participants may participate at the same time. This is providing the increase of space from the standard mockup for the additional subjects does not degrade the comparison tests. Under these conditions, the participants with the least physical agility should be in the most critical positions.
c. The subgroups should be as neatly alike as possible for physical agility, age, sex, and weight. This can be achieved by first dividing the group by age and sex then subdividing each age/sex group at random into the required number of subgroups.
d. Each subgroup should test each configurat ion, but the order of trials should be different for each subgroup as well as chosen in accordance with the Latin Square Principle. This principle is that each configuration be tried once by each subgroup and appear once in each possible order. Thus if there are two configurations to be tested and, therefore, two subgroups A and B, then Subgroup A should first try the standard configuration followed by the proposed configuration; Subgroup B should perform the trials in the reverse order. This arrangement removes the effects of an individuals learning, fatigue, and agility.
127 Recording of Trials. Recording should be done as follows:
a. Motion pictures or video recordings, sound or silent, should be made to analyze the trials for difficulties with an exit, individual escape times, and other performance factors.
b. A large clock with a second hand should be placed in the camera field so time can be recorded or synchronized electric cameras may be used with the time superimposed in the film processing. A signal light to show the beginning and end of each trial should also be arranged in view of the camera.
c. Evacuation time should be rounded to the nearest second. The timed demonstration is performed per the Evacuation section of AC 20-118A.
Evaluation of Results. The evaluation should be performed as follows:
a. The effectiveness of the proposed exit or exits compared with the standard exit or exits is determined by comparison of the average time of the subgroups to pass through each exit tested. The effect of subgroup learning is canceled by the Latin Square Principle.
b. It may be possible one group contains one or two persons who find it difficult to go through the exits. The Latin Square Principle will cancel such unbalance between subgroups.
c. It may happen that an individual ma y, through chance, have considerable difficulty with an exit, but their performance may compare with average performance of other individuals. A study of the individual escape times will enable such events to be evaluated and will aid in the final determination of the acceptability of the proposed exit or exits.
d. A proposed exit configuration is acceptable when its egress time is equal to or less than the time required to pass through the standard exit.
Type Certificate Data Sheet (TCDS). An equivalent level of safety finding should be part of the type certification basis and noted on the TCDS. Suggested wording is, “Equivalent Safety Findings: Section 3.387 of the CAR and Section 23.807 of 14 CFR part 23, emergency (particular) exit in accordance with AC 23-17C, Systems and Equipment Guide for Certification of Part 23 Airplanes and Airships.”
Amendment 23-36 and Subsequent This amendment is explained by Notice 86-19 as follows: “The issue of number and location was addressed by one proposal to require that for all airplanes with a seating capacity of two or more, excluding airplanes with canopies, have at least one emergency exit on the opposite side of the cabin from the main door specified in Section 23.783. There have been egress difficulties experienced with center line
128 engine airplanes with a seating capacity of two or more, excluding those airplanes with canopies, and no emergency exit or door opposite the main cabin door. In some cases, occupants have had to kick out windows to egress the airplanes after survivable accidents.”
Prior policy in this AC allows the blocking by cargo of emergency exits that are not required for the crewmembers, and it prohibits the removal of approved emergency exits. Current § 23.807 requires two exits on opposite sides of the airplane for a seating capacity of two or more. This was required by CAR 3, § 3.387, for airplanes with a seating capacity of 5 to 15 persons. Amendment 23-36, dated 9/14/88, changed § 23.807 to two exits on opposite sides of the airplane for two or more seating capacity.
Amendment 23-46 and Subsequent A proposed revision in NPRM 90-20 explains this amendment as follows: “For standardization between the airworthiness requirements for commuter category and transport category airplanes, and to simplify the alternate emergency exit standards proposed in this notice, the FAA proposes to move certain requirements of Sec.
23.807(d)(1) to a new paragraph (f) in Sec. 23.783 and proposes a new paragraph
(d)(3) in Sec. 23.807. The standards in proposed Sec. 23.783(f) require that each passenger entry door qualify as a floor level emergency exit and provide requirements for integral stairs when installed at a passenger entry door. The standards in proposed 23.807(d)(3) require that each emergency exit that is not a floor level exit either be located over the wing or, if not less than six feet from the ground, have an acceptable means to assist the occupants in descending to the ground. There are no substantive differences between the requirements in proposed Sec. 23.783(f) or in proposed Sec. 23.807(d)(3) and those requirements proposed to be removed from Sec. 23.807(d)(1).”
A proposed revision to the NPRM explains the following: “This notice proposes new requirements for emergency exit ditching provisions for multiengine airplanes that are type certificated to the airworthiness standards of part 23. The FAA anticipates an increase in the use of commuter category airplanes and multiengine normal category airplanes in over water operation. Airports developed near large bodies of water increase the number of departures and approaches that are conducted over water. Since ditching provisions may be critical for occupant egress following an emergency landing in water, the standards in proposed Sec. 23.807(e) ensure the availability of exits for emergency egress following an emergency landing in water.”
Amendment 23-49 and Subsequent The following flow chart is valid for emergency exit in normal, utility, and acrobatic category airplanes.
129 Non-Commuter Emergency Exit Flowchart One Emergency Exit on Opposite Side of Cabin from Main Door Passenger Exits Available to Crew One Emer. Exit on Each Side of A/C OR Top Hatch
IN CREW AREA Pilot’s Compartment Separated from Passenger Compartment by a door that will likely block Pilot’s Escape Require One Exit in Pilot’s Compartment Exits near a Hazard
RECONFIGURE Multiengine A/C One Exit Above WL on Each Side of Aircraft OR Overhead Hatch STOP START A A No Yes Yes No Yes No No Yes
23.807(a)(1)
23.805(a)
23.805(a)
23.807(a)(3)
23.807(a)(3)
23.807(a)(4)
23.807(a)(4)
23.807(e)(1)
23.807(e)(1)(2)
Amendment 23-62 and Subsequent
In Docket No. FAA-2009-0738, the Discussion of the Regulatory Amendments stated: In the event of a ditching, this change in § 23.807 provides an alternative to meeting the current requirement for an emergency exit, above the waterline, on both sides of the cabin for multiengine airplanes. Section 23.807 allows the placement of a water barrier in the doorway before the door would be opened as a means to comply with the above waterline exit requirement. This barrier could be used to slow the inflow of water. The FAA has approved the use of this barrier as an alternative to the above waterline exit for several airplanes by issuing an ELOS finding.
This amendment allows the use of a water dam in a door that is to be used as an emergency exit in a water landing without the need for an equivalent level of safety. A commuter category airplane must meet the size requirements of § 23.807(d) with the water dam in place.
The Final Rule adopts Section 23.807 as proposed.
23.811 Emergency exit marking
There is no corresponding rule in CAR 3.
The corresponding airworthiness criteria is section 4.36, Airship Design Criteria, FAA-P-8110-2, Change 2.
Amendment 23-36 and Subsequent
For small airplanes with emergency exits that open from the outside, the FAA recommends that markings be added to the outside of all exits as follows:
a. Outline the exit with a band of a contrasting color from the surrounding fuselage surface.
b. Mark the corners of the exit in a prominent manner.
c. Outline the exit handle with a band of a contrasting color.
d. Mark the exit with any other prom inent visual identification scheme.
e. Install a decal on the outside surface of the exit or the surrounding surface adjacent to the exit that shows the means of opening the exit, including any special instructions if applicable.
Section 23.811(a) is specifically intended to be applicable to exterior emergency exit markings and placards. It does not stipulate the color of these markings and placards, except that they must be obviously identifiable from outside the airplane. Section
23.1557(d) specifically requires that each placard and operating control for each exit must be red. Also, a placard must be near each emergency exit control and must clearly show the location of that exit and its method of operation.
Since the emergency exit exterior markings are obviously identifiable from the outside of the airplane, to further require red placards that show the location of these exits does not make sense. There might be instances where the red placard may not be clearly identifiable because of the exterior color of the fuselage. Section 23.807 gives further guidance on adding external markings to emergency exits. Not one of the recommendations specifies the use of red placards. Other subparagraphs of § 23.811 require the use of red markings when the subject involves the interior of the airplane. Being consistent with these facts, therefore, FAA interprets the intent of § 23.1557(d) to be applicable to the interior of the airplane.
Passenger exit signs should have an initial luminescence of at least 160 microlamberts, and should be replaced when its luminescence decreases below 100 microlamberts.
131 Amendment 23-46 and Subsequent
The explanation for this amendment in NPRM 90-20 states as follows “The emergency exit marking standards for transport category airplanes, as stated in Sec.
25.811, have specific requirements that go beyond the current commuter category airplane emergency exit marking standards. Therefore, this notice proposes to add a new Sec. 23.811(c) providing additional airworthiness requirements for emergency exit marking that would be applicable when certification to the emergency exit provisions of Sec. 23.807(d)(4) is requested. The standards in proposed Sec.
23.811(c)(1), which are similar to the requirements of Sec. 25.811(a), ensure conspicuous marking for each emergency exit, its means of access and its means of opening for rapid identification and operation of the exits in an emergency condition.
The standards in proposed Sec. 23.811(c)(2), which are similar to the requirements of Sec. 25.811(b), ensure that the airplane occupants can readily identify and locate the emergency exits on the opposite side of the cabin from where they are seated. The standards in proposed Sec. 23.811(c)(3), which are similar to the requirements of Sec. 25.811(c) that ensure that the airplane occupants can locate the emergency exits when the cabin is filled with dense smoke. The standards in proposed Sec.23.811(c)(4), which are similar to the requirements of Sec. 25.811(e)(1), ensure that the operating handle and the instructions for opening the emergency exits are shown by a marking that is readable from a distance of 30 inches. The standards in proposed Sec. 23.811(c)(5), which are similar to the requirements of Sec.
25.811(e)(2), ensure that there is sufficient lighting to allow identification of the passenger entry door operating handle. The standards in proposed Sec. 23.811(c)(6), which are similar to the requirements of Sec. 25.811(e)(4), ensure the ease of access and operation of a passenger entry door with a locking mechanism that is released by a rotary motion of the handle. The standards in proposed Sec. 23.811(c)(7), which are similar to paragraphs (1) and (2) or Sec. 25.811(f), ensure that the emergency exits are externally marked so that they can be readily identified in conditions of low lighting or poor visibility. These proposed requirements would result in emergency exits that are easier to locate and open in adverse conditions.”
23.812 Emergency lighting
There are no corresponding rule or airworthiness criteria in CAR 3 or the Airship Design Criteria.
Amendment 23-46 and Subsequent
The explanation for this rule adopted in Amendment 23-46 states as follows: “This proposal adds requirements for an emergency lighting system, to be applicable when an applicant for type certification chooses to comply with the alternate emergency exit provisions of proposed Sec. 23.807(d)(4) of this part. The proposal defines specific minimum requirements for supplying power, arming, and activating the emergency lighting system. The impact-activation requirement is consistent with that for emergency locator transmitters. The proposal also includes illumination, function, and survivability requirements for the emergency lighting system. An emergency lighting system complying with these proposed requirements would aid occupants in locating the emergency exits and getting to those exits after an emergency landing.”
23.813 Emergency exit access
There are no corresponding rule or airworthiness criteria in CAR 3 or the Airship Design Criteria.
Amendment 23-36 and Subsequent
A change to this amendment was added by Final Rule docket 25147 as follows: “In addition, the requirements of Section 23.807(d)(4) are moved to a new Section
23.813, titled Emergency exit access", in this final rule.”
See § 23.807 Means of Compliance for policy on acceptance of seatbacks obstructing emergency exits that can be easily moved.
Amendment 23-46 and Subsequent
The explanation in NPRM 90-20 for this amendment states as follows: “This proposal adds requirements to ensure emergency exit accessibility, to be applicable when an applicant for type certification choose to comply with the alternate emergency exit provisions of proposed Sec. 23.807(d)(4) of this part. Structural failures or yielding of the airframe can occur during an emergency landing or minor crash event that may result in one or more emergency exits or the passenger door becoming unopenable. Since the total number of exits available for emergency egress can be fewer with the alternate emergency exit requirements, this proposal defines minimum unobstructed aisle width at the passenger entry door and adds other requirements to ensure that any partitions or doorways within the passenger compartment will not hinder occupant access to the exits during an emergency situation.”
23.815 Width of aisle
There are no corresponding rule or airworthiness criteria in CAR 3 or the Airship Design Criteria.
Amendment 23-34 and Subsequent
This rule, adopted “from SFAR 41, Sec. 5(e), Doors and Exits, paragraph (k), applies to commuter category airplanes”. The main passenger aisle width is the minimum distance between seats measured without occupants. This distance is measured without compressing the seat fabric or cushions, and with the seats and other aisle constraints in their most adverse position. If the seats can swivel and the distances can be less than the rule requires, the most adverse position may be defined with placards or flight manual limitations to require locking them in either a forward or aft facing position for taxi, takeoff, and landing. This is acceptable only when those positions give an aisle distance that meets or exceeds the requirement.
Even though 23.815 does not specifically state a minimum height clearance, any design evaluation by the FAA would default to the required aisle width extending from the floor to ceiling. Any identified obstructions within that floor-to-ceiling area will need to be considered in terms of their effect on the ability of occupants to evacuate the airplane. Strict compliance to 23.815 may be found, or an ELOS to
23.815 may be used as part of the project's approval documentation. This would be subject to FAA review and approval.
Amendment 23-46 and Subsequent
A proposed revision in NPRM 90-20 explains this amendment as follows: “This proposal requires increased aisle widths to be applicable when an applicant for type certification chooses to comply with the alternate emergency exit provisions of proposed Sec. 23.807(d)(4) of this part. The proposed increased aisle width requirements are intended to ensure that the airplane passengers can reach an exit in an emergency situation even though the floor structure has been warped or there are seats or other items protruding into the normal aisle space.”
The Final Rule, Docket 26324, added the following preamble material: “The purpose of the increased aisle width is to increase the probability that occupants can reach an exit during an emergency situation, even though seats or other items may be protruding into the normal aisle space. It is recognized that changes in aisle width have little significant effect on evacuation if minimum airworthiness standards for cabin safety and emergency exits are first met. However, part of the intent of this amendment is to establish these minimum alternative requirements for part 23 commuter category airplanes consistent with those for part 25 small transport category airplanes. This proposal is adopted as proposed.”
Thus, this rule is applicable only to commuter category airplanes.
23.831 Ventilation
The corresponding rule in CAR 3 is CAR 3.393.
The corresponding airworthiness criteria is section 4.38, Airship Design Criteria, FAA-P-8110-2, Change 2.
See AC 21-4B, Special Flight Permits for Operation of Overweight Aircraft, for ventilation of ferry fuel tanks.
Original Issue and Subsequent
The use of an alternate air supply, either automatic or manual, that picks up air from within the engine compartment is unacceptable for cabin ventilation because of possible contamination from either fuel, oil, or exhaust leaks.
Halon 1301 may be safely used in concentrations up to 10 percent in airplane cabins.
Ventilation in airplane cabins is sufficient for the agent to disburse in less than five minutes, so the time limit need not be considered if the concentration is held below the 10 percent limit. Halon 1211, however, should not be used in airplane cabins.
The regulation on allowable carbon monoxide (CO) concentration is given in part 23, § 23.831(a): carbon monoxide concentration may not exceed one part in 20,000 parts of air.
Tests to verify compliance with part 23, § 23.831(a) are done as part of the original type certification of an aircraft. This is done when a modification that has a possible effect on the compliance to part 23, § 23.831(a) is made and when Co is verified or suspected in operation.
Two acceptable methods of detecting carbon monoxide are given in AC 20-32B. These are acceptable either for a TC applicant, an STC applicant, a parts manufacturer approval applicant, an FAA field approval applicant, or an owner/operator. Other methods of verifying compliance to part 23, § 23.831(a) can be used if they are shown to provide acceptable results.
Amendment 23-34 and Subsequent
The source for this revision is shown by NPRM 83-17 as “Part 135, Appendix A, section 60, and SFAR No. 41, section 4(c)(3), which incorporates § 25.831(d) by reference”. For pressurized commuter category airplanes, if hazardous accumulations of smoke are found to be reasonably probable in the cockpit area, smoke evacuation to a non-hazardous level should be readily accomplished from full pressurization to minimum safe levels (per 14 CFR, part 91, § 91.211). Smoke
136 evacuation procedures should be included in the AFM, Emergency or Non-Normal (Abnormal) Procedures Section, or on approved placards.
1. What is the acceptable level of smoke, in the cockpit, as a result from this type of test?
The test to show compliance to § 23.831(b) is for "all" fires that are possible not just engine fires. Conservatism requires the test begin with smoke sufficient to obscure the instrument panel. The plane must remove this smoke without depressurizing the plane below safe limits per § 23.831(b).
2. What is the acceptable level of toxicity of the smoke?
FAA has a requirement for carbon monoxide in § 23.831(a), but no other material.
The applicant must determine what combustion by-products will be generated from the reasonably probable failure of an engine fire in a reciprocating engine.
3. Three minutes or five minutes for clearing smoke from the cockpit?
The three-minute period is acceptable not to remove all smoke but to permit the pilot to safely fly the plane (see the flight instruments).
4. What does "readily accomplished" mean?
This rule came from part 135, Appendix A, which was based on § 25.831(d). It means the flight crew can easily activate the depressurization system while seated and belted in the cockpit. In a single pilot airplane, this means from the left seat.
5. What does "without depressurizing beyond safe limits," mean?
The source for this rule was the same as question 4. Part 91 specifies that a flight crew can operate at 14,000 feet cabin pressure for 30 minutes. This is the maximum level the plane can be depressurized without supplemental oxygen for operation above 14,000 feet for more than 30 minutes. However, applicants can use Time of Useful Consciousness for an emergency descent as in a pressurization failure. They must allow time for the cockpit to clear of smoke sufficiently for the flight crew to safely begin the descent to 14,000 feet or below.
6. Can the smoke evacuation test be done on the ground?
Yes, a ground test is acceptable IF the applicant can clearly show that all relevant test boundary conditions match the respective flight conditions (such as airflows, and pressure fields.). If an applicant elects to have a cabin altitude limiter, the ground test must be conducted at or above the setting of the limiter (example: test site above 14,000 feet Mean Sea Level (MSL), if the limiter is set at 14,000), otherwise no.