document number: 2021-000-0022 rev a federal aviation

Document Number: 2021-000-0022 Rev A

9111 E Douglas Avenue, Suite 100, Wichita, KS 67207 Phone: 316-260-2258

March 9, 2021 Ben Tyson – Program Manager Federal Aviation Administration Wichita Aircraft Certification Office 1801 Airport Road, Room 100 Wichita, KS 67209 Subject: Exemption Request for Airbus A321-231/232 Series Passenger to Freighter Conversion

STC Reference: 3S Certification, ODA-833355-CE Project Number: 3S18-027-01, Letter Number

2021-000-0022 Dear Mr. Tyson, The purpose of this letter is for 3S Certification to petition the FAA for an exemption for the Airbus A321-231/232 Series aircraft from 25.785(j) [Amdt 25-88]; 25.791(b)(e) [Amdt 25-72] 25.813(b)(4) [Amdt 25-128]; 25.857(e) [Amdt 25-142] ; and 25.1447(c)(1) [Amdt 25-116]. 3S Certification is petitioning for the exemption in accordance with paragraph 14 CFR 11.81 under Petitions for Rulemaking and for Exemptions.

Project Description

3S is applying for a new STC for the conversion of Airbus SAS Model A321-231/232 airplanes from an all-passenger configuration to an all-cargo configuration. This STC will be effective for A321-231/232 series airplanes and will include installation of a main deck left side cargo door, a main deck Class E cargo compartment that is accessible during flight and associated systems.

Aircraft Make and Model

Airbus SAS A321-200 (A321-231/232) series found on TCDS A28NM

Approved Aircraft List

The Airbus SAS A321 is listed in the 3S ODA Approved Aircraft Listing, document number 100-0100-V01-02.

The petitioner requests relief from the following regulations:

Section 25.785(j) Amendment 25-88,

(j) If the seat backs do not provide a firm handhold, there must be a handgrip or rail along each aisle to enable persons to steady themselves while using the aisles in moderately rough air.

Section 25.791(b)(e) Amendment 25-72

(b) Signs that notify when seat belts should be fastened and that are installed to comply with the operating rules of this chapter must be operable by a member of the flightcrew and, when illuminated, must be legible under all probable conditions of cabin illumination to each person seated in the cabin. (e) Symbols that clearly express the intent of the sign or placard may be used in lieu of letters.


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Section 25.813(b)(4) Amendment 25-128

Each required emergency exit must be accessible to the passengers and located where it will afford an effective means of evacuation. Emergency exit distribution must be as uniform as practical, taking passenger distribution into account; however, the size and location of exits on both sides of the cabin need not be symmetrical. If only one floor level exit per side is prescribed, and the airplane does not have a tailcone or ventral emergency exit, the floor level exit must be in the rearward part of the passenger compartment, unless another location affords a more effective means of passenger evacuation. Where more than one floor level exit per side is prescribed, at least one floor level exit per side must be located near each end of the cabin, except that this provision does not apply to combination cargo/passenger configurations. In addition—

(b) Adequate space to allow crewmember(s) to assist in the evacuation of passengers must be provided as follows:

(4) For each Type C, I or II exit, an assist space must be provided at one side of the passageway if an assist means is required by §25.810(a).

Section 25.857(e) Amendment 25-142

(e) Class E. A Class E cargo compartment is one on airplanes used only for the carriage of cargo and in which— (1) [Reserved] (2) There is a separate approved smoke or fire detector system to give warning at the pilot or flight engineer station; (3) There are means to shut off the ventilating airflow to, or within, the compartment, and the controls for these means are accessible to the flight crew in the crew compartment; (4) There are means to exclude hazardous quantities of smoke, flames, or noxious gases, from the flight crew compartment; and (5) The required crew emergency exits are accessible under any cargo loading condition.

Section 25.1447(c)(1), Amendment 25-116

If oxygen dispensing units are installed, the following apply: (c) If certification for operation above 25,000 feet is requested, there must be oxygen dispensing equipment meeting the following requirements: (1) There must be an oxygen dispensing unit connected to oxygen supply terminals immediately available to each occupant, wherever seated, and at least two oxygen dispensing units connected to oxygen terminals in each lavatory. The total number of dispensing units and outlets in the cabin must exceed the number of seats by at least 10 percent. The extra units must be as uniformly distributed throughout the cabin as practicable. If certification for operation above 30,000 feet is requested, the dispensing units providing the required oxygen flow must be automatically presented to the occupants before the cabin pressure altitude exceeds 15,000 feet. The crew must be provided with a manual means of making the dispensing units immediately available in the event of failure of the automatic system.


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The petitioner’s supportive information is as follows:

3S Certification is currently engaged in the development of a modification of an Airbus A321-231/232 Passenger airplane to an A321-231/232 “Converted Freighter” configuration. This modification results in the conversion of the main deck of the airplane from a passenger cabin to a Class E cargo compartment (as defined in 14 CFR 25.857(e)). The interior reconfiguration of the flight deck removes the forward galley but does not add or subtract any supernumerary/attendant seats.

The new A321-231/232 cargo aircraft will provide air cargo transportation in the same manner as other freight/cargo airplanes in its class (e.g. the Boeing 737-800BCF). When additional crew is carried in the existing attendant seats, the carriage of such persons is defined in 14 CFR 121.583. This petition seeks relief to allow additional crew carriage and access to the main deck Class E cargo compartment while in flight.

Specific information for 25.785(j)

The requirement to have handholds installed is justified for the use by occupants who need to frequently walk along the aisle. This is not applicable to the considered configuration. For the considered category of occupants, the recommendations to remain seated with the seat belt fastened, as far as practicable, will be made in order to limit moving.

Specific information for 25.791(b)(e)

The small number of the flight crew and non-flying crew and their proximity to each other enhances the ability of the flight crew to communicate instructions to the non-flying crew. Therefore, specific fasten safety belt signs are not necessary as a means to increase safety.

Section 25.813(b)(4) Amendment 25-128

The categories of occupants for which this exemption is sought are qualified aeronautical personnel (reference Section 121.583). Furthermore, they are trained as to the autonomous use of emergency equipment and emergency exit operation. It will also be required that the operator only allows access to these seats to persons found able to perform these tasks on their own.

The existing slides at L1 and R1 entry door slides will be retained for egress and use as rafts in the event of a water landing. See Figures 1 through 3.

The ropes/lanyards installed at the openable windows in the flight compartment will be retained as the emergency egress assist means for these exits.

The ropes/lanyards installed at the openable windows in the flight compartment will be retained as the emergency egress assist means for these exits.


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Figure 1 – A321-231/232 Emergency Exits

Figure 2 – A321-231/232 L1 & R1 Emergency Exits


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Figure 3 – A321-231/232 L1 & R1 Emergency Exits with Rigid Cargo Barrier

Specific information for 25.857(e)

While no additional supernumerary seats are being installed as part of this STC, some configurations of the A321-231/232 will have as a maximum of supernumerary occupancy of four persons. There will be allowed as many as four jump/attendant seats in the flight deck and crew areas. Use of these seats by cargo operator support personal may be needed for the safe handling of cargo during loading and offloading of a cargo flight. Support personnel are especially important if the airplane is carrying perishable goods, hazardous materials or live animals. Refer to Figure 4 for additional layout information for the supernumerary seats.


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Figure 4 – A321-231/232 Flight Deck and Crew Area

As such, this petition requests supernumerary access to the main deck Class E compartment during flight to assist with carriage of livestock/animals or hazardous materials when carried. 3S proposes to add the necessary safety features, procedures and limitations which will ensure the safety of personal entering the Class E compartment:

1. Entrance to the compartment shall be allowed in flight only on airplanes complying with all the following requirements. Entrance shall not be allowed during taxi, takeoff or landing. A placard located on the rigid cargo barrier partition in a conspicuous place adjacent to the door which is visible from the entrance side shall include these instructions. See Figure 5.


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Figure 5 – A321-231/232 Rigid Cargo Barrier Placard

2. Only certain cargo configurations will allow for access to the cargo compartment. The AFMS will include instructions and requirements for access. Configurations must allow for adequate space to freely move about the compartment and visual annunciators must be visible in all locations.

3. The door to the Class E compartment must be closed at all times except for entry and exit. The compartment must not be entered in case of fire in the Class E compartment. A placard located on the rigid cargo barrier partition in a conspicuous place adjacent to the door which is visible from the entrance side shall include these instructions. The configuration and location of the rigid cargo barrier and door and shown in figure 6. The door opening is 24” wide by 48” tall with 5” corner radii.


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Figure 6 – A321-231/232 Rigid Cargo Barrier

4. The maximum number of persons allowed into the cargo compartment will be 3 persons at any one time. Each person entering the class E compartment in flight shall be provided with a portable oxygen bottle and mask which shall be stored in a common area. The amount of oxygen shall be sized adequately for continuous and uninterrupted use during worst case flight duration following decompression. The bottle and mask must be carried by the persons entering the compartment at all times. The persons entering the compartment shall be trained in how to use the equipment.

5. Adequate lighting will be provided. The control for the lighting will use a switch and will be located in a place to prevent the lighting inadvertently being turned off with a person in the cargo compartment.

Interior emergency lighting will be provided by retaining, or relocating as necessary, existing lights, exit sign/light for Door 1 Left/Right, and battery packs. The existing lights will continue to provide lighting to the escape slides at the L1 and R1 door. The existing emergency lighting in the flight compartment will be retained. Emergency lighting will be provided in the crew area. All other


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emergency lights and battery packs in the passenger cabin that are not needed will be removed. Emergency lighting and exit signs will be provided as depicted in Figure 7:

Figure 7 – A321-231/232 Emergency Lighting & Sign Locations

6. A cargo compartment alert system shall be installed to provide the following:

a. An automatically activated aural decompression signal which is immediately recognizable in the accessible area of the cargo compartment, in order to work crew to don oxygen masks and return to their seat.

Note: This warning in combination with the portable oxygen equipment is considered an alternative, equivalent to the requirement of automatic presentation of masks (ref. 25.1447(c)(1).

b. A flight crew operated visual annunciation that is recognizable in the accessible area of the cargo compartment to indicate during turbulence that all personal must return to their seats. This alert will be provided via the PA and a speaker installed mid cabin.

c. A flight crew operated visual annunciation that is recognizable in the accessible area of the cargo compartment to indicate during a fire in the Class E compartment that all persons must return to their seats and ensure that the smoke barrier door is closed. This visual


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annunciation will be provided via 3 alert panels that will be located fwd, mid, and aft. See figure 8 & 9 for example of alert panel.

7. The pre-flight briefing shall include an explanation of all the alert signals, their meaning and the required response.

8. All the limitations shall be included in the flight manual limitation section.

9. In addition, the flight manual shall instruct the flight crew to brief the supernumeraries before each flight about the limitations and procedures in case of entry into the Class E compartment in flight.

Figure 8 – Crew Alert Panels located in Cargo Compartment – Fwd, Mid, and Aft


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Figure 9 – Cockpit annununciators

Specific information for 25.1447(c)(1)

All occupants in the flight deck will have available the same quick donning flight crew-type oxygen masks as those previously used and certified on the A321-231/232 which are not automatically presented. The location of the existing supernumeraries, and the crew’s high level of training, will allow the crew to easily command non-operating occupants to don the masks, and verify their proper usage. In addition, the crew has a public address system which can be heard throughout the flight deck and lavatory. This combination provides an acceptable level of safety with regard to the requirements defined by §25.1447(c)(1) for automatic mask presentation. See Figure 10 and 11 for crew, passenger, and portable oxygen locations.


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Figure 10 – A321-231/232 Portable Oxygen & Mask Location (Existing OEM Location)

Figure 11 – A321-231/232 Emergency Equipment Location

The flight deck will be outfitted with a portable walk around oxygen bottle for use by supernumeraries when accessing the main deck Class E cargo compartment. The bottle will be equipped with a supplemental passenger oxygen mask and will supply at least 3.6 liters of oxygen per minute at a 40,000 ft. cabin altitude for not less than 25 minutes. The Class E cargo compartment will not have human occupants for taxi, takeoff or landing.


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The lavatory will utilize the existing drop down oxygen mask for use by a lavatory occupant during a decompression event. The bottle will supply at least 3.6 liters of oxygen per minute at a 40,000 ft. cabin altitude for not less than 25 minutes. The lavatory area will not be utilized for taxi, takeoff or landing.

Specific information for 25.807(g)(1), 25.807(i)(1), 25.809(a), 25.810(a)(1), 25.812(e), 25.812(L)(1), and 25.1449.

Consideration was given to 25.807(g)(1), 25.807(i)(1), 25.809(a), 25.810(a)(1), 25.812(e), 25.812(1)(1), and 25.1449.

25.807(g)(1): Since overwing exits are not provided, this project must provide Type III exits. Both the L1 and R1 are 1.85m (72.8 in) by .81m (31.9 in) with corner radii below the 7 inches. The reduction of the opening due to the cargo barrier is 72.8 inches by 28.1 inches. The regulation requirement for type III is “not less that 20 inches wide by 36 inches high”. The exit from the cargo area is 24” wide by 48” tall with 5” corner radii. Because these exits meet the criteria of 25.807(g)(1) 3S is not requesting an exemption for this regulation.

25.807(i)(1): This requirement for “one exit above the waterline in each side of the airplane, meeting at least the dimensions of a Type IV exit” is also met by the L1 and R1 doors. Both are located above the waterline and meet the size criteria of Type IV exits. Therefore, 3S is not requesting an exemption for this regulation.

25.809(a): This requirement for an unobstructed view from the emergency exit. Both the L1 and R1 doors (unchanged from the OEM installation) provide a viewing window in the door. Therefore, 3S is not requesting an exemption for this regulation.

25.810(a)(1): This requirement for non over-wing emergency exits to have a means for occupants to descend to the ground is met by retaining the existing slides for the L1 and R1 doors. Therefore, 3S is not requesting an exemption for this regulation.

25.812(e): This requirement for floor emergency escape path marking will be verified in a compliance walk-thru to ensure that emergency lighting and marking is adequately provided and not obscured. Therefore, 3S is not requesting an exemption for this regulation.

25.812(L)(1): This requirement that no more than 25% of emergency lighting system is inoperative after any single transverse vertical separation will be verified as part of certification ground testing. Therefore, 3S is not requesting an exemption for this regulation.

25.1449: This requirement that there must be a means to allow the crew to determine whether oxygen is being delivered to the dispensing equipment will be verified as part of certification ground testing. Therefore, 3S is not requesting an exemption for this regulation.


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Public Interest

The granting of the requested exemption is in the public interest as allowing the entrance of persons into the Class E cargo compartment during flight optimizes the safety conditions of the cargo operation, makes the operation more efficient, and improves the utility of the airplane.

Summary

The rules from which we seek exemption and a brief description of each exemption is as follows:

Section 25.785(j) Amendment 25-88, requires a “firm handhold” along each aisle. This is not applicable to the cargo configuration. The requirement to have handgrips installed is justified for the use of cabin attendants who need to frequently walk along the aisle. For the considered category of occupants, the recommendations to remain seated with the seat belt fastened, as far as practicable, will be made in order to limit moving.

Section 25.791(b)(e) Amendment 25-72 provides construction and visibility standards for "Fasten Seat Belt" signs. This is not applicable in the cargo configuration. The small number of the flight crew and non-flying crew and their proximity to each other enhances the ability of the flight crew to communicate instructions to the non-flying crew. In the limited occasions when crew are not in proximity, a “return to seat” aural warning may be engaged. Therefore, specific fasten safety belt signs are not necessary as a means to increase safety.

Section 25.813(b)(4) Amendment 25-128 requires adequate space to allow crewmemebers to assist in evacuation of passengers through exits. In this case, the crew are trained as to the autonomous use of emergency equipment and emergency exit operation. It will also be required that the operator only allows access to these seats to persons found able to perform these tasks on their own.

Section 25.857(e) Amendment 25-142 requires, in pertinent part, that when a Class E cargo compartment is installed on the airplane, the airplane must be used for carriage of cargo only. While no additional supernumerary seats are being installed as part of this STC, some configurations of the A321-231/232 have as many as four jump/attendant seats in the flight deck compartment. Use of these seats by cargo operator support personal may be needed for the safe handling of cargo during loading and offloading of a cargo flight. Support personnel are especially important if the airplane is carrying perishable goods or live animals. As such, this petition requests supernumerary access to the main deck Class E compartment during flight to assist with carriage of livestock/animals or hazardous materials when carried. 3S proposes to add necessary safety features, procedures and limitations which will ensure the safety of personal entering the Class E compartment.

Section 25.1447(c)(1), Amendment 25-116, requires, in pertinent part, that oxygen masks be immediately available to each seated occupant, be automatically deployed with manual backup, and exceed the number of seats by ten percent, with the extra units distributed evenly throughout the

document number: 2021-000-0022 rev a federal aviation

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