Figure 1. LRBL Design Dimensions
18 I nc hes Wires, Cables Tu bing , e t c.
Systems Standoff Di stance LRBL 30 Inches Stay Out Plu gge d Panel (Blow -Out) (minimum)Floor StayOutArea Plu g Panel (Blowout) 18 I nc hes Wires, Cables Tu bing , e t c.
Standoff Di stance LRBL 30 Inches Stay Out Plu gge d Panel (Blow -Out) 18 I nc hes Wires, Cables Tu bing , e t c.
Standoff Di stance LRBL 30 Inches Stay Out Plu gge d Panel (Blow -Out) (minimum)Floor StayOutArea30 I nc hes Plu g Panel (Blowout) 18 I nc hes Wires, Cables Tu bing , e t c.
Systems Standoff Di stance LRBL 30 Inches Stay Out Plu gge d Panel (Blow -Out) (minimum)Floor StayOutArea Plu g Panel (Blowout) 18 I nc hes Wires, Cables Tu bing , e t c.
Standoff Di stance LRBL 30 Inches Stay Out Plu gge d Panel (Blow -Out) 30 Inches 18 18 I nc hes Wires, Cables Tu bing , e t c.
Standoff Di stance LRBL Inches 30 Inches Stay Out Plu gge d Panel (Blow -Out) 30 Inches(minimum)Floor StayOutArea30 I nc hes Plu g Panel (Blowout) 18 I nc hes Wires, Cables Tu bing , e t c.
Systems Standoff Di stance LRBL 30 Inches Stay Out Plu gge d Panel (Blow -Out) (minimum)Floor StayOutArea Plu g Panel (Blowout) 18 I nc hes Wires, Cables Tu bing , e t c.
Standoff Di stance LRBL 30 Inches Stay Out Plu gge d Panel (Blow -Out) 18 I nc hes Wires, Cables Tu bing , e t c.
Standoff Di stance LRBL 30 Inches Stay Out Plu gge d Panel (Blow -Out) (minimum)Floor StayOutArea30 I nc hes Plu g Panel (Blowout) 18 I nc hes Wires, Cables Tu bing , e t c.
Systems Standoff Di stance LRBL 30 Inches Stay Out Plu gge d Panel (Blow -Out) (minimum)Floor StayOutArea Plu g Panel (Blowout) 18 I nc hes Wires, Cables Tu bing , e t c.
Standoff Di stance LRBL 30 Inches Stay Out Plu gge d Panel (Blow -Out) 30 Inches 18 18 I nc hes Wires, Cables Tu bing , e t c.
Standoff Di stance LRBL Inches 30 Inches Stay Out Plu gge d Panel (Blow -Out) 30 Inches(minimum)Floor StayOutArea30 I nc hes Plu g Panel (Blowout) 18 I nc hes Wires, Cables Tu bing , e t c.
Systems Standoff Di stance LRBL 30 Inches Stay Out Plu gge d Panel (Blow -Out) (minimum)Floor StayOutArea Plu g Panel (Blowout) 18 I nc hes Wires, Cables Tu bing , e t c.
Standoff Di stance LRBL 30 Inches Stay Out Plu gge d Panel (Blow -Out) 18 I nc hes Wires, Cables Tu bing , e t c.
Standoff Di stance LRBL 30 Inches Stay Out Plu gge d Panel (Blow -Out) (minimum)Floor StayOutArea30 I nc hes Plu g Panel (Blowout) 18 I nc hes Wires, Cables Tu bing , e t c.
Systems Standoff Di stance LRBL 30 Inches Stay Out Plu gge d Panel (Blow -Out) (minimum)Floor StayOutArea Plu g Panel (Blowout) 18 I nc hes Wires, Cables Tu bing , e t c.
Standoff Di stance LRBL 30 Inches Stay Out Plu gge d Panel (Blow -Out) 30 Inches 18 18 I nc hes Wires, Cables Tu bing , e t c.
Standoff Di stance LRBL Inches 30 Inches Stay Out Plu gge d Panel (Blow -Out) 30 Inches(minimum)Floor StayOutArea30 I nc hes Plu g Panel (Blowout) 18 I nc hes Wires, Cables Tu bing , e t c.
Systems Standoff Di stance LRBL 30 Inches Stay Out Plu gge d Panel (Blow -Out) (minimum)Floor StayOutArea Plu g Panel (Blowout) 18 I nc hes Wires, Cables Tu bing , e t c.
Standoff Di stance LRBL 30 Inches Stay Out Plu gge d Panel (Blow -Out) 18 I nc hes Wires, Cables Tu bing , e t c.
Standoff Di stance LRBL 30 Inches Stay Out Plu gge d Panel (Blow -Out) (minimum)Floor StayOutArea30 I nc hes Plu g Panel (Blowout) 18 I nc hes Wires, Cables Tu bing , e t c.
Systems Standoff Di stance LRBL 30 Inches Stay Out Plu gge d Panel (Blow -Out) (minimum)Floor StayOutArea Plu g Panel (Blowout) 18 I nc hes Wires, Cables Tu bing , e t c.
Standoff Di stance LRBL 30 Inches Stay Out Plu gge d Panel (Blow -Out) 30 Inches 18 18 I nc hes Wires, Cables Tu bing , e t c.
Standoff Di stance LRBL Inches 30 Inches Stay Out Plu gge d Panel (Blow -Out) 30 Inches(minimum)Floor StayOutArea30 I nc hes Plu g Panel (Blowout)
(4) Where the criteria provided in paragraph 8a(3) would conflict with the requirements of § 25.795(c)(2), maximizing system separation takes precedence. However, in this case, the applicant should consider adding protection from fragments and large structural deformation to systems that must be run in proximity to the LRBL
(5) Systems shielding and/or inherent protection should be able to withstand fragment impacts from 0.5-inch diameter 2024-T3 aluminum spheres traveling 430 feet per second. The ballistic resistance of 0.09-inch thick 2024-T3 aluminum offers an equivalent level of protection.
System designs must incorporate features that minimize the risk of their failure due to large displacements of the structure to which they are attached. This may include flexibility in both the systems and/or their mountings. In the absence of test evidence or alleviating rationale, provisions should allow for a minimum 6-inch displacement in any direction from a single point force applied anywhere within the protected region. The applicant may also incorporate frangible attachments or other features that would preclude system failure.
b. Traditionally, the LRBL was chosen where there was intrinsic structural reinforcement.
However, the applicant may take other measures to meet the intent of the rule. An example would be a containment system. Such an approach would require the concurrence of the applicable Aircraft Certification Office and the Transport Airplane Directorate to establish the appropriate criteria.
c. In most circumstances, it is preferable to reduce the cabin pressure differential to zero.
Reduction of cabin pressure is an extremely effective way to minimize structural damage in the event of a detonation.
d. The goal of LRBL procedures is to mitigate the effects of an in-flight explosion and to enhance aircraft survivability through use of prior planning, training, and available resources.
In-flight emergency safety procedures recommended by the Department of Homeland Security serve as a guide for airlines and crews to refine specific emergency procedures in their Flight Operations Manuals and in initial and recurrent training programs.
e. Section 121.295 requires that information on the LRBL be available to the crew during flight. The information must be concise and easy to understand.
f. Effectiveness of the LRBL does not need to be verified by test.
Ali Bahrami Manager, Transport Airplane Directorate Aircraft Certification Service 6