Federal Aviation Administration (FAA), DOT.
Final special conditions.
These special conditions are issued for the Boeing Model 777 series airplanes. This airplane will have novel or unusual design features associated with overhead cross aisle stowage compartments. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for these design features. These special conditions contain the additional safety standards the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards.
November 15, 2006.
Jayson Claar, FAA, Airframe/Cabin Branch, ANM–115, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., Renton, Washington, 98057–3356; telephone (425) 227–2194; facsimile (425) 227–1232.
On April 20, 2005, Boeing Commercial Airplane Group, Seattle, Washington, applied for a supplemental type certificate to permit installation of overhead cross aisle stowage compartments in Boeing 777 series airplanes. The Boeing Model 777 series airplanes are large twin engine airplanes with four or five pairs of Type A exits. The Boeing 777 airplanes can be configured with various passenger capacities and ranges.
The regulations do not address the novel and unusual design features associated with the installation of overhead cross aisle stowage compartments installed on the Boeing Model 777, making these special conditions necessary. Generally, the requirements for overhead stowage compartments are similar to stowage compartments in remote crew rest compartments (i.e., located on lower lobe, main deck or overhead) already in use on Boeing Model 777 and 747 series
Under the provisions of § 21.101, Boeing Commercial Airplane Group must show that the Boeing Model 777, as changed, continues to meet the applicable provisions of the regulations incorporated by reference in Type Certificate No. T00001SE or the applicable regulations in effect on the date of application for the change. The regulations incorporated by reference in the type certificate are commonly referred to as the “original type certification basis.” The regulations incorporated by reference in Type Certificate No. T00001SE for the Boeing Model 777 series airplanes include Title 14 Code of Federal Regulations (CFR), part 25, as amended by Amendments 25–1 through 25–100, with exceptions, for various models. Refer to Type Certificate No. T00001SE, as applicable, for a complete description of the certification basis for this model, including certain special conditions that are not relevant to these special conditions.
If the Administrator finds the applicable airworthiness regulations (part 25 as amended) do not contain adequate or appropriate safety standards for the Boeing Model 777 because of a novel or unusual design feature, special conditions are prescribed under the provisions of § 21.16.
In addition to the applicable airworthiness regulations and special conditions, the Boeing Model 777 must comply with the fuel vent and exhaust emission requirements of 14 CFR part 34 and the noise certification requirements of 14 CFR part 36.
The FAA issues special conditions, as defined in § 11.19, under § 11.38, and they become part of the type certification basis under § 21.101.
Special conditions are initially applicable to the model for which they are issued. Should the applicant apply for a change to modify any other model included on the same type certificate to incorporate the same or similar novel or unusual design feature, the special conditions would also apply to the other model under § 21.101.
The Boeing Model 777 will incorporate the following novel or unusual design features: the installation of powered lift-enabled stowage compartments that rise into the overhead area and lower into the cabin.
The overhead cross aisle stowage compartments are configured to allow stowage of galley type standard containers as well as coats, bags, and other items typically stowed in closets or bins. These stowage compartments may be located above the emergency exit cross aisles of Boeing Model 777 series airplanes. Because the compartment is lowered into the main cabin, it could affect egress if it cannot be raised again. The overhead compartment may lower into a cross aisle as defined in § 25.813, but it may also lower into other potential egress paths. For the purposes of these special conditions, the same criteria apply, whether or not the egress path is required by § 25.813. Therefore, as used in these special conditions, the term “overhead cross aisle stowage compartment” addresses all such compartments.
Each stowage compartment is accessed from the main deck by a powered lift that lowers and raises the stowage compartment between the overhead and the main deck. In addition, the lift can be hand cranked down and up in the event of a power or lift motor failure. A smoke detection system will be provided in the overhead cross aisle stowage compartments.
In general, the requirements listed in these special conditions for overhead cross aisle stowage compartments are similar to those previously approved for overhead crew rest compartments in earlier certification programs, such as for the Boeing Model 777 and Model 747 series airplanes. These special conditions establish compartment access, power lift, electrical power, smoke/fire detection, fire extinguisher, fire containment, smoke penetration, and compartment design criteria for the overhead cross aisle stowage compartments. The overhead stowage compartments are not a direct analogy to stowage compartments in remote crew rest compartments installed and certified for Boeing Model 777 series airplanes, but the safety issues raised are similar. Features similar to those considered in the development of previous special conditions for fire protection will be included here also. The requirements provide an equivalent level of safety to that provided by other Boeing Model 777 series airplanes with similar overhead compartments.
The FAA's Aircraft Certification Service will administer these special conditions, which specify requirements for design approvals (that is, type design changes and supplemental type certificates) of overhead cross aisle stowage compartments.
The Aircraft Evaluation Group of the FAA's Flight Standards Service must evaluate and approve the operational use of overhead cross aisle stowage compartments prior to use. The Aircraft Evaluation Group must receive all instructions for continued airworthiness, including service bulletins, prior to the FAA accepting and issuing approval of the modification.
Appropriate placards, or other means, are required to address door access and locking to prohibit or prevent passenger access, and operation of the overhead storage compartment. There must also be a means to preclude anyone from being trapped inside the stowage compartment, if it is large enough for a person to enter. If there is more than one door providing access, each door must be equipped with these means.
The power lift must be designed so the overhead stowage compartment will not jam in the down position, even if lowered on top of a hard structure. The lift must operate at a speed, and stop above the floor at such a height, that allows anyone underneath the compartment to move clear without injury. The lift controls must be placed clear of the compartment door and must be pressed continuously for lift operation. Training on power lift operation procedures must be added to appropriate manuals.
There must be a means to manually operate the lift that is independent of the electrical drive system. The lift must be operable by a range of occupants, including a fifth percentile female. The manual means must be capable of lowering the overhead stowage compartment quickly to the main deck to fight a fire. The manual system must be capable of raising the compartment quickly so the cross aisle or other egress path (if applicable) is not blocked in an emergency. If electrical or manual power is removed, there must be a means, such as a brake, to prevent the compartment from unrestricted movement, i.e., falling. Training on
For compartments larger than 25 cubic feet, a handheld fire extinguisher appropriate to fight the kinds of fire likely to occur in the overhead stowage compartment must be provided. This handheld fire extinguisher must be adjacent to the overhead compartment. This extinguisher must be in addition to those required for the passenger cabin.
This special condition requires either the installation of a manually activated fire extinguishing system that is accessible from outside the overhead stowage compartment, or a demonstration that the crew could satisfactorily perform the function of extinguishing a fire under the prescribed conditions. A manually activated built-in fire extinguishing system would be required only if a crewmember could not successfully locate and get access to the fire during a demonstration where the crewmember is responding to the alarm. For the duration of the flight, the system must have adequate capacity to suppress any fire occurring in the stowage compartment considering the fire threat, volume of the compartment, and the ventilation rate.
The design of the compartment must provide means to exclude hazardous quantities of smoke or extinguishing agent originating in the compartment from entering other occupied areas. The means must take into account the time period during which the compartment may be accessed to manually fight a fire, if applicable.
Smoke entering any other compartment occupied by crewmembers or passengers, when access to the stowage compartment is opened to manually fight a fire, must dissipate within five minutes after the access to the stowage compartment is closed.
During the one-minute smoke detection time (see Special Condition No. 7), penetration of a small quantity of smoke (one that would dissipate within 3 minutes under normal ventilation conditions) from this overhead stowage compartment into an occupied area on this airplane configuration would be acceptable based on the limitations placed in this and other associated special conditions. These special conditions place sufficient restrictions in the quantity and type of material allowed in the overhead stowage compartment that threat from a fire in this remote area would be equivalent to that experienced on the main cabin.
If a built-in fire extinguishing system is used in lieu of manual fire fighting, then the fire extinguishing system must be designed so that no hazardous quantities of extinguishing agent will enter other compartments occupied by passengers or crew.
The material used to construct the overhead stowage compartment must meet the flammability requirements for compartment interiors in § 25.853 and be fire resistant. Depending on the size of the compartment, certain fire protection features of Class B cargo compartments are also required. Enclosed stowage compartments equal to or exceeding 25 ft
Enclosed stowage compartments equal to or greater than 57 ft
The overhead stowage compartment smoke or fire detection and fire suppression systems (including airflow management features which prevent hazardous quantities of smoke or fire extinguishing agent from entering any other compartment occupied by crewmembers or passengers) is considered complex in terms of paragraph 6d of Advisory Circular (AC) 25.1309–1A, “System Design and Analysis.” The FAA considers failure of the overhead stowage compartment fire protection system (that is, smoke or fire detection and fire suppression systems) in conjunction with an overhead stowage fire to be a catastrophic event. Based on the “Depth of Analysis Flowchart” shown in Figure 2 of AC 25.1309–1A, the depth of analysis should include both qualitative and quantitative assessments (reference paragraphs 8d, 9, and 10 of AC 25.1309–1A).
The requirements to enable crewmember(s) quick access to the overhead stowage compartment and to locate a fire source inherently places limits on the amount of baggage stowed and the size of the overhead stowage compartment. The overhead stowage compartment is limited to stowage of galley type standard containers as well as coats, bags, and other items typically stowed in closets or bins. It is not intended to be used for the stowage of other items. The design of such a system to include other items may require additional special conditions to ensure safe operation.
Notice of proposed special conditions No. 25–06–09–SC for the Boeing Model 777–200 series airplanes was published in the
These special conditions are applicable to the Boeing Model 777 series airplanes with overhead cross aisle stowage compartments. Should Boeing Commercial Airplane Group apply later for a change to Type Certificate No. T00001SE to include another model on the same type certificate incorporating the same novel or unusual design feature, the special conditions would apply to that model as well.
Under standard practice, the effective date of final special conditions would be 30 days after the date of publication in the
This action affects only certain novel or unusual design features on the Boeing Model 777 series airplanes. It is not a rule of general applicability and affects only the applicant who applied to the FAA for approval of these features on the airplane.
Aircraft, Aviation safety, Reporting and recordkeeping requirements.
The authority citation for these special conditions is as follows:
49 U.S.C. 106(g), 40113, 44701, 44702, 44704.
Accordingly, pursuant to the authority delegated to me by the Administrator, the following special conditions are issued as part of the type certification basis for Boeing Model 777 series airplanes. Each overhead cross aisle stowage compartment and the adjacent area, including the structural frame, mechanical system and drive motor, must meet the following requirements:
1.
2.
(a) The lift controls must be placed so the operator is clear of the lift and designed such that the controls must be pressed continuously for lift operation.
(b) The lift must raise and lower the stowage compartment at a slow enough rate, and stop above the floor at such a height, that anyone underneath can easily move clear without injury.
(c) Stowage compartment operation training procedures must be added to the appropriate flight attendant manuals.
3.
(a) This manual means must be independent of the electrical drive system
(b) The manual means must be accessible and operable by a range of occupants, including a fifth percentile female.
(c) The manual means must be capable of lowering the stowage compartment to the main deck quickly enough to fight a fire in the stowage compartment before overhead cross aisle stowage compartment fire containment is compromised.
(d) The manual means must be capable of quickly raising the stowage compartment such that the cross aisle, or other egress path is not blocked in the event of an emergency.
(e) Stowage compartment firefighting training procedures must be added to the appropriate manuals.
(f) The lift system must include a means, such as a brake, to retain the overhead cross aisle stowage compartment in any position of travel when the manual or electric drive force is removed.
4.
5.
6.
7.
(a)
(b)