pair of Type I exits equipped with slides, 50 for a cabin with a pair of improved Type 1 exits (Type "B"), and 70 for a cabin with a pair of Type A exits. Those passenger capacities were 73.3 percent, 62.5 percent, and 63.6 percent, respectively, of the ratings in Table 2 for the Type I and Type A exits and the rating of 80 for the improved Type I granted by Exemption No.
1573. Since the exits in this case would not be the only exits available, the recommended percentage is the highest one granted by the exemptions rounded up to the next 5-percent level. On most airplanes with two or more pairs of floor level exits, except for combis, the capacities of dead-end zones will be quite low since § 25.807(c) also requires that floor level exits be near each end of the cabin.
(2) The second is the proximity of the exits to each other along the length of the passenger cabin taking into account the ratings (as determined by exit type) of the exits. This results in an arrangement where passenger cabin zones are sized according to the type of exits which bound the zone.
The ‡ 15-percent tolerance from the nominal location, as allowed in paragraph 6b(2) (vi), was developed by analyzing current transport airplane configurations and selecting a tolerance band which encompassed the majority of the airplanes. Airplanes which fell outside the tolerance band ranged from
15.9 percent to over 25 percent beyond the nominal location for at least one The method is based on providing uniformly distributed exits for a typical single class, maximum passenger seating configuration in the airplane.
configurations which include first and or business class seating. This may therefore, should be taken when reviewing seating result in overloading the economy class zones while still keeping the total seating configuration at or below the maximum for the entire airplane.
Consideration may be given to airplane configurations which, by virtue of the number and types of exits installed in the airplane, have a theoretical maximum passenger seating configuration well beyond the practical maximum seating capacity. For example, for a twin-aisle airplane having four pairs of Type A exits, the theoretical maximum passenger seating capacity would be 440. It, nowever, the airplane were only b1g enough to seat 3/0 passengers at the highest density seating, then only three pairs of lype A exits and one pair of Type I exits would be required, by Table 2, for that number of passengers. It would then be permissible to evaluate the airplane as if one of the Type A exit pairs had been derated to Type I exits (thereby limiting the maximum passenger capacity to 375), or, alternatively, to derate two of the Type A exit pairs to Type "B" exits (thereby limiting the maximum passenger capacity to 380 or 370, depending on the Type "B" rating). This could be useful to the applicant, particularly when one of the three passenger zones is significantly smaller than the other two. The same derating of exits, for purposes of the analysis, would be acceptable if the applicant proposed to purposefully limit the passenger seating capacity of the airplane to a lesser number than theoretically allowable. (When exits are derated for purposes of analyzing their proximity to each other, their full rating may still be used for calculating passenger zone capacities. See Example 3 in Appendix 1.)
6. ACCEPTABLE METHOD.
5 Par 5
a. General considerations.
(1) In completing the calculations specified under the method of analysis (paragraphs 6b(1), (2), (3)), the exit ratings of Table 2 should be used for all exit types with the following exceptions:
For airplanes whose maximum passenger seating configuration is established by Table 1 and is greater than 39, including those airplanes whose type certification basis allows extra seats for installing slides, the rating for Type 1 exits should be determined for each airplane separately.
Development of the rating for Type I exits may also be required for airplanes whose exit configuration is approved by the granting of a petition for exemption or by a finding of an equivalent level of safety, e.g., the BAe-146 and the 757. The rating is determined by subtracting the ratings for the non-Type I exits, as found in Table 2, from the maximum of the range in which the maximum capacity falls in Table 1 (which may be increased by 10 for certain airplanes as described in paragraph 5d) and then dividing the remainder by the number of pairs of Type I exits. For example, for an airplane with a space-limited seating capacity of 145, Table 1 requires that it have two pairs of Type I exits and two pairs of Type III exits. With such an exit configuration, however, the airplane would be eligible for a maximum passenger seating configuration of 179. Therefore, the rating for the Type I exits for this airplane, for analytical purposes, would be (179 - 2(35)) / 2 =
54.5 which is rounded up to 55.
(ii) For airplanes with one pair each of Type II and Type III exits with a maximum passenger seating configuration between 20 and 39, assign a rating of 20 to the Type Il exits and a rating of 19 to the Type III exits.
(2) For airplanes which have two pairs of adjacent Type Ill exits, these may be considered in the analysis in paragraph 6b to be one exit pair with a rating of /o passengers, provided that the exits are no more than three seat rows apart. Since this "double III" exit does consist of two separate exits, however, care should be taken to ensure that passenger flow to the "double III" comes from both directions. A "double III" should never be located, for example, at the end of a passenger cabin. For purposes of defining the start or end of a zone bounded by two pairs of Type Ill exits, establish a new centerline midway between the two exits. Seats whose front studs are forward of the new centerline will be considered to be in the forward zone, seats aft of the centerline in the aft zone. If the exits are more than three rows apart, they should be considered as separate exits with a passenger zone between them.
(3) it a ventral or tall-cone exit or any other unpaired exit is installed, but no increase in passenger seating is allowed, the exit is not to be considered in the analysis. Exit pairs which are installed, but which have been determined to be excess exits, as noted in § 25.807(c) (c)(6), Amendment 25-32, should normally not be considered in the analysis. however, the excess exits are needed in order to meet the criteria specified in this AC, then those exits should no longer be considered as excess exits.
(4) When the exits in an exit pair are not directly opposite each other, the analysis should consider the exit distribution on each side of the Par 6
airplane separately. For example, if the forward exits of an airplane are staggered such that the centerline of the left hand exit is at fuselage station (FS) 100 and the right hand exit is at FS 130, the airplane should be analyzed as if the forward exits were at FS 100 and then the airplane should be analyzed again as if the forward exits were at FS 130.
should be acceptable in order for the airplane to be acceptable.
b. The method of analysis for determining compliance with the uniform distribution requirement.
(1) An evaluation should be made to determine passenger distribution throughout the passenger cabin with respect to exits. In making this determination, the following steps should be taken:
(1) The passenger seating within any zone should not exceed the sum of the ratings of the two pairs of exits bounding the zone. For example, the passenger capacity in a zone bounded by two pairs of Type A exits should not exceed 220 (2 x 110). For airplanes which have passengers seated forward of the first exit or aft of the last exit in the passenger cabin, the first or last zone in the airplane would be from the start or end of the passenger cabin to the closest pair of exits. For these zones, the capacity should not exceed 75 percent of the rating of the single pair of exits bounding the zone.
while traversing the airplane from nose to tail and also from tail to nose, • exce any ed of the ratings of the exits ne passenger capacity should not exceed the sum of the ratings of the exits included in the consecutive zones being analyzed.
(iii) The maximum seating capacity should be determined by referring to Tables 1 and/or 2 or, as necessary, the type certificate data sheet for the specific airplane.
(2) An evaluation should be made to determine the distribution of the exits with respect to the fuselage and to each other, taking into account the type of each exit. In making this determination, the following steps should be taken:
(i) Determine the passenger cabin length. An adjustment is the red chest the or less of sets, or the cabin exted the exit and start or end the cabin at the exit centerline. If there are four or more rows, the cabin starts or ends at the location of the front stud of the most remote seat row;
(ii) Determine the exit unit value of each exit in the airplane.
Then determine the number of exit units in each zone of the airplane by adding the exit unit values of the exits bounding the zone. When a zone beyond the irst and last pair of exits is three rows or less, do not give that zone ar exit unit rating. in addition, determine the total number of exit units in the airplane by adding the total of each zone (this results in non-end-of-
(iii) Divide the cabin length by the total number of exit units to determine the value of the fuselage length factor;
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(iv) Starting at the beginning of the passenger cabin (which will be either the centerline of the first exit or the centerline of the front stud of the most forward pair of seats), determine the nominal location of the centerline of the next (or first) pair of emergency exits by multiplying the fuselage length factor by the number of exit units in Zone A and adding the result to the fuselage station at the start of the cabin. The nominal location of the centerline of the next pair of exits is determined by multiplying the fuselage length factor by the number of exit units in Zone B and adding that number to the previous nominal location. This procedure is repeated until all the nominal exit locations are determined. The starting and end points are fixed by the configuration and need not be calculated;
(v) At each nominal exit location, determine the offset of the proposed/actual exit from the nominal location. With the exception of two pairs of Type III exits within three rows of each other, however, two adjacent pairs of exits should not be closer than the distance of the fuselage length
(vi) Calculate the offset as a percent of the length of the cabin. No proposed/actual exit should be more than t 15 percent from the nominal exit location.
(3) The nominal exit location, and the allowed ‡ 15 percent deviation rom that location, is not applicable when it would position the exit in ar area that could be hazardous to passengers during an emergency evacuation.
Such areas are in the vicinity of propeller planes, engine intakes or pylons, landing gear, and the wing leading and trailing edges.
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8/13/90 AC 25.807-1
7. EXAMPLES. See Appendix 1 for four examples using this method of analysis.
LEROY A. KEITH Manager, Transport Airplane Directorate, Aircraft Certification Service, ANM-100 Par 7 9
Appendix 1 APPENDIX 1 EXAMPLE 1 Alp, and i, with no passenger seats located beyond the forward and aft exits.
The centerlines of exits 1 through 5 are FS 200, FS 750, FS 1200, FS 1875, and FS 2200, respectively. Zone A is bounded by a pair of I's and a pair of A's, Zone B by two pairs of A's, Zone C by a pair of A's and a pair of I's, and Zone D by two pairs of I's.
The maximum seating configurations of the four zones and sequential combinations of these zones are as follows:
(a) Individual zone passenger capacities:
Zone A: 155 (45 + 110);
Zone B: 220(110 + 110);
Zone C: 155 (110 + 45);
Zone D: 90(45 + 45).
(b) Sequential zone passenger capacities - nose to tail:
Zones A + B: 265 (45 + 110 + 110);
Zones A + B + C: 310 (45 + 110 + 110 + 45).
Sequential zone passenger capacities - tail to nose:
Zones D + C: 200(45 + 45 + 110);
Zones D + C + B: 310 (45 + 45 + 110 + 110).
(c) Maximum passenger seating configuration:
Zones A + B + C + D: 355 (The exit limit per Table 2).
Exit distribution with respect to fuselage is as follows:
(a) The length of the cabin is 2000 inches (FS 2200 - FS 200).
(b) The number of exit units in each zone is as follows:
Zone A: 4.25 (1.25 + 3.0);
Zone B: 6.0 (3.0 + 3.0);
Zone C: 4.25 (3.0 + 1.25);
Zone D: 2.5 (1.25 + 1.25);
Airplane total: 17.0.
(c) Fuselage length factor = 117.6 inches (2000"/17).
(d) Nominal exit location:
Exit 1: FS 200 (by definition, as it is at the start of the passenger cabin);
Exit 2: FS 699.8 (200 + (117.6 x 4.25));
Exit 3: FS 1405.4 (699.8 + (117.6 × 6.0));
Exit 4: FS 1905.2 (1405.4 + (117.6 × 4.25));
Exit 5: FS 2200 (by definition, as it is at the end of the passenger cabin).
(e) Exit offsets:
Appendix 1 Exits 1 and 5: Offset = 0;
Exit 3: offset = 255.4" (1505.-4 - 1200);
Exit 4: Offset = 25.4" (1905.2 - 1875).
(f) Percent of exit offset:
Exits 1 and 5: 0%;
Exit 2: 2.5% (50.2/2000 x 100%);
Exit 3: 10.3% (205.4/2000 × 100%) ;
Exit 4: 1.3% (25.4/2000 x 100%);
All exits are offset less than 15 percent from the nominal locations and are acceptable.
(g) By inspection, no two exits are closer together than the fuselage length factor of 117.6 inches (see 6b(2) (v)).
EXAMPLE 2 Airplane 2 has a passenger cabin with four pairs of exits: a Type I, III, and I, in that order, and a tail-cone exit which has been determined to allow an increase in seating contiguration of 25. There are also 12 passengers (two rows of seats) seated forward of the first pair of exits. The centerlines of exits 1 through 4 are at FS 200, FS 600, FS 640, and FS 945, respectively.
The tail-cone exit floor-level opening in the passenger cabin is at FS 1200.
The first seat in the airplane is at FS 110. Since there are only 40 inches between the two pairs of Type III exits, there must be less than three rows of seats between them. Therefore, for purposes of the analysis, they can be considered to be one double Type III exit with centerline at FS 620.
Therefore, Zone A is bounded by the start of the passenger cabin and a I, Zone B by a I and the double III, zone C by the double III and a I, and Zone D by a I and the tail-cone exit.
This configuration is defined in Table 1 with the addition of the tail-cone rating of 25 for a total of 204 passengers. The calculated rating for Type I exits for this airplane is 55 ((204 - (25 + (2 x 35))) / 2).
The maximum seating configurations of the three zones and sequential combinations of these zones are as follows:
(a) Individual zone passenger capacities:
Zone A: 41 (.75 of 55, rounded down);
one 6: 125 (55 + (2 x 35)) one C: 125 ((2 × 35) + 55) Zone D: 80 (55 + 25).
(b) Sequential zone passenger capacities - nose to tail:
Zones A + B: 125(55 + (2 × 35));
Zones A + B + C: 180 (55 + (2 X 35) + 55).
Sequential zone passenger capacities - tail to nose:
Zones D + C + B: 204 (the limit per Table'1 plus 25 for the 150 (25 + 55 + (2 × 35));
tail cone).
Appendix 1
(c) Maximum passenger seating configuration:
Zones A + B + C + D: 204 (the limit per Table 1 plus 25 for the tail cone).
Exit distribution with respect to fuselage is as follows:
The length of the passenger cabin is 1000 inches (FS 1200 - FS 200).
Note that the passenger cabin was deemed to start at the centerline of the forward exits rather than at the front stud of the first row of seats. This is because Zone A is too small, i.e., three rows or less, to warrant an exit unit rating.
(b) The number of exit units in each zone and in the airplane is as follows:
Calculate the exit unit value for the Type I exits: 55/35 = 1.57 rounded down to 1.5;
Calculate the exit unit value for the tail-cone exit: 12/35 = .34 rounded down to .25.
Zone A: 0;
Zone B: 3.5 (1.5 + 2);
Zone C: 3.5 (2 + 1.5);
Zone D: 1.75 (1.5 + .25); §÷ 25);
Airplane total: 8.75.
(c) Fuselage length factor = 114.3 inches (1000"/8.75).
(d) Nominal exit locations:
Exit 1: FS 200 (by definition, as it is at the start of the passenger cabin);
Exit 2: FS 600 (200 + (114.3 x 3.5));
Exit 3: FS 1000 (600 + (114.3 x 3.5));
Exit 4: FS 1200 (by definition, as it is at the end of the passenger cabin).
(e) Exit offsets:
Exits 1 and 4: Offset = 0;
Exit 2: Offset = 20 (620 - 600);
Exit 3: Offset = 55 (1000 - 945).
(f) Percent of exit offset:
Exit 1 and 4: 0%;
Exit 2: 2.0% (20/1000 × 100%);
Exit 3: 5.5% (55/1000 x 100%);
All exits are offset less than 15 percent from the nominal locations and are acceptable.
(g) By inspection, no two exits, the two Type Ill exits excluded, are closer together than the fuselage factor of 114.3 inches.
EXAMPLE 3 Airplane 3 has a dual-aisle passenger cabin with four pairs of exits: Type A, A, I, and A, in that order. The centerline of the exits are at FS 160, FS 600, FS 900, and FS 1600, respectively. Zone A is bounded by two pairs of 3
Appendix 1 A's, Zones B and C by a pair of A's and a pair of I's. Because of the size of the airplane, the passenger seating capacity is effectively space-limited to 304 passengers.
The maximum seating configurations of the three zones and sequential combinations of these zones are as follows:
(a) Individual zone passenger capacities:
Zone A: 220 (110 + 110);
Zone B: 155 (110 + 45);
Zone C: 155 (45 + 110).
Sequential zone passenger capacities - nose to tail:
Zones A + 8: 265 (110 + 110 + 45).
Sequential zone passenger capacities - tail to nose:
Zones C + B: 265 (110 + 45 + 110).
(c) Maximum passenger seating configuration:
Zones A + B + C: 375. This is the exit limit of the airplane using Table 2.
Exit distribution with respect to fuselage is as follows:
(a) The length of the cabin is 1440 inches (FS 1600 - FS 160).
(b) The number of exit units in each zone is as follows:
Zone A: 6.0 (3.0 + 3.0);
Zone B: 4.25 (3.0 + 1.25);
Zone C: 4.25 (1.25 + 3.0);
Airplane total: 14.5.
(c) Fuselage length factor = 99.3 inches (1440i/14.5).
(d) Nominal exit location:
Exit 1: FS 160 (by definition, as it is at the start of the passenger cabin);
Exit 2: FS 755.8 (160 + (99.3 x 6));
Exit 3: FS 1177.8 (755.8 + (99.3 × 4.25));
Exit 4: FS 1600 (by definition, as it is at the end of the passenger cabin).
(e) Exit offsets:
Exits 1 and 4: Offset = 0;
Exit 2: Offset = 155.8" (755.8 - 600);
Exit 3: Offset = 277.8" (1177.8 - 900).
(f) Percent of exit offset:
Exits 1 and 4: 0%;
Exit 2: 10.8% (155.8/1440 × 100%);
Exit 3: 19.3% (277.8/1440 × 100%);
Exit 3 is offset by more than 15 percent and therefore falls outside the acceptable tolerance bounds for locating that exit.
Appendix 1 The configuration does not meet this guidance for uniform distribution of exits.
(9) By inspection, no two exits are closer together than the fuselage length factor of 99.3 inches.
Because the airplane is space-limited to a maximum of 304 passengers, the airplane can be reanalyzed, since the maximum seating capacity would require only two pairs of Type A and two pairs of Type I exits be installed (per Table 2). Since Zone B is the smallest zone, designate exit number 2 as being derated to a Type I exit for purposes of the exit distribution analysis.
The maximum seating configurations of the three zones and sequential combinations of these zones are as follows:
(a) Individual zone passenger capacities:
Zone A: 220 (110 + 110);
Zone B: 155 (110 + 45);
Zone C: 155 (45 + 110).
(b) Sequential zone passenger capacities - nose to tail:
Zones A + B: 265 (110 + 110 + 45).
Sequential zone passenger capacities - tail to nose:
Zones C + B: 265 (110 + 110 + 45).
(c) Maximum passenger seating configuration:
Zones A + B + C: 375 (the limit per Table 2).
Exit distribution with respect to fuselage is as follows;
(a) The length of the passenger cabin is 1440 inches (FS 1600 - FS 160).
(b) The number of exit units in each zone and in the airplane is as follows:
Zone A: 4.25 (3.0 + 1.25);
Zone B: 2.5 (1.25 + 1.25);
Zone C: 4.25 (1.25 + 3.0);
Airplane total: 11.0.
(c) Fuselage length factor = 130.9 inches (1440"/11).
(d) Nominal exit locations:
Exit 1: FS 160 (by definition, as it is the start of the passenger cabin);
Exit 2: FS 716.3 (160 + (4.25 × 130.9));
Exit 3: FS 1043.6 (716.3 + (2.5 x 130.9));
Exit 4: FS 1600 (by definition, as it is at the end of the passenger cabin).
(e) Exit Offsets:
Exits 1 and 4: Offset = 0;
Appendix 1 Exit 2: Offset = 116.3i (716.3 - 600);
Exit 3: Offset = 143.6i (1043.6 - 900).
(f) Percent of exit offset:
Exits 1 and 4: 0%;
Exit 2: 8.1% (116.3/1440 × 100%);
Exit 3: 10.0% (143.6/1440 × 100%);
All exits are offset less than 15 percent from the nominal locations and are acceptable. The reanalysis based on the actual passenger maximum capacity shows that this configuration is have been self-imposed by the manufacturer.)
(g) By inspection, no two exits are closer together than the fuselage length factor of 130.9 inches.
EXAMPLE 4 airplane 4 has three pairs of exits in this order: lype 1, ili, and I, with four rows of seats aft of the most aft exit and with the forward pair of exits offset from one another. The centerlines of the exits are as follows: Ll - FS 100, R1 - FS 220, L2 and R2 - FS 500, L3 and R3 - 850. The seats in the first row in the airplane have their front studs at FS 120 on the left side and FS 90 on the right side (there are four rows of seats forward of the R1 exit) and the seats in the last row in the airplane have their front studs at FS 970.
This configuration is defined in Table 1 for a total of 139 passengers. The calculated rating for Type I exits for this airplane is 52 ((139-35)/2).
Analysis of left-hand side:
The maximum seating configurations of the three zones and sequential combinations of these zones are as follows:
(a) Individual zone passenger capacities:
Zone A: 87 (52 + 35);
Zone B: 87 (35 + 52);
Zone C: 39 (.75 x 52).
(b) Sequential zone passenger capacities - nose to tail:
Zones A + B: 139 (52 + 35 + 52).
Sequential zone passenger capacities - tail to nose:
Zones C + B: 87 (52 + 35).
(c) Maximum passenger seating configuration:
Zones A + B + C: 139. This is the exit limit of the airplane using Table 1.
Exit distribution with respect to fuselage is as follows:
(a) The length of the cabin is 870 inches (FS 970 - FS 100).
Appendix 1
(b) The number of exit units in each zone is as follows:
Zone A: 2.25 (1.25 + 1.0);
Zone B: 2.25 (1.0 + 1.25);
Zone C: 1.25;
Airplane total: 5.75.
(c) Fuselage length factor = 151.3 inches (870/5.75).
(d) Nominal exit location:
Exit 1: FS 100 (by definition, as it is at the start of the passenger cabin); * 208(0 = 151 3 35).
Exit 2: FS 440.4 (100 + (151.3 × 2.25));
(e) Exit offsets, proposed versus nominal:
Exit 1: Offset = 0;
Exit 3: offset = 59.2" (550 - 480.8):
(f) Percent of exit offset:
Exit 1: 0%;
Exit 2: 6.9% (59.6/870 x 100%);
Exit 3: 8.0% (69.2/870 x 100%);
All exits are offset less than 15 percent from the nominal locations and are acceptable.
(g) By inspection, no two exits are closer together than the fuselage length factor of 151.3 inches.
Analysis of right-hand side:
The maximon settinesentiqurarias to tow four zones and sequential
(a) Individual zone passenger capacities:
Zone A: 39 (.75 x 52);
Zone B: 87 (52 + 35);
Zone C: 87 (35 + 52);
Zone D: 39 (.75 x 52).
(b) Sequential zone passenger capacities - nose to tail:
Zones A + B: 87(52 + 35);
Zones A + B + C: 139 (52 + 35 + 52).
Sequential zone passenger capacities - tail to nose:
Zones D + C: 87 (52 + 35);
Zones D + C + B: 139 (52 + 35 + 52).
(c) Maximum passenger seating configuration:
Zones A + B + C + D: 139. This is the exit limit of the airplane using Table 1.
Exit distribution with respect to fuselage is as follows:
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