C-18 Mk 5 (Passenger/Freight)
Exercise 5: Assessing the ELoS Argument
Overview
In this scenario you are a member of the MAA evaluating the certification evidence provided by the CCBT DT to contribute to the Type Certification Review (TCR) for a design change to the C-18 Mk 5.
This TCR will require you to analyse and assess an Equivalent Level of Safety (ELoS) argument. This will give you some valuable insight into the MAA’s role as the independent regulator during this stage of the MACP.
A scenario for a non-compliance with the C-18 Mk 5 was detailed in Exercise 4. The DT have provided an MCRI with an ELoS proposal.
In your role as MAA, you were consulted by the DT when they generated the ELOS and have seen the evidence that is detailed below. You are to assess the ELoS the TAA submitted in the form of an MCRI and decide whether the ELoS argument merits agreement and an Equivalent Safety Finding (ESF).
You are to brief the other syndicates using the ppt slide template provided and explain to them whether you (as the MAA) would accept the ELOS and provide an ESF or reject the ELoS argument, giving reasons why.
You have a maximum of 10 minutes for your brief.
C-18 Mk 5 Troop and Kit (TaK) Fit
The C-18 Mk 5 is a passenger/freight variant. It has a cargo/freight door on the port side of the fuselage to the rear of the wing. The C-18 Mk 5 also has a quick fit floor system that permits re-role of the Air System from a full passenger role to a freighter role using pallets.
An Urgent Capability Requirement (UCR) has been raised to mitigate a Tactical Air Transport capability gap, enabling rapid deployment of Troops along with the required kit. To meet the UCR this Major design change introduces a Troop and Kit (TaK) Fit cabin layout.
The C-18 Mk 5 TaK Fit incorporates a configuration where the forward section of the cabin comprises 54 passenger seats mounted onto seat pallets and the aft section of the cabin is configured with 6 pallet-mounted luggage containers. A restraint net is provided across the top of each of the 6 luggage containers to secure the contents. Freight and dangerous air cargo will not be carried in these containers; they are designed specifically for the transport of personal carry-on luggage (rucksacks and soft bags).
The luggage containers are COTS and have been sourced from an aircraft interior design company in order to meet UCR timeframes. Redesign and manufacture of the containers within the UCR timeframe has not been possible. Figures 1 and 2 illustrate this role fit on the C-18 Mk 5.
Figure 1 – C-18 Mk 5 Increased Baggage Stowage Capacity Figure 2 – C-18 Mk 5 Increased Baggage Stowage Capacity
The Issue with the revised role fit
In assessing the design change, a non-compliance with the agreed TCB has been identified for the mixed passenger and luggage container configuration by the TAA.
Def Stan 00-970 Part 5, Clauses CS 25.815, UK25.815a – Aisle Width.
The introduction of the mixed passenger and luggage container configuration will result in the aisle width being 110mm less than the minimum certification requirement (510mm) above the 640mm height threshold, in the aft section of the cabin due to the width of the baggage containers.
The TAA decided that CS25.803 and UK25.803a – Emergency Evacuation (see below for details) could be affected by this change due to the reduction in aisle width and the possible impact on time to egress the aircraft in an emergency. As a result of this decision an emergency evacuation demonstration was performed.
Def Stan 00-970 Part 5 Sect 2.4 Sub Part D, Clauses CS25.803 – Emergency Evacuation.
CS25.803 requires that for aircraft with a seating capacity of more than 44 passengers that the aircraft can be evacuated within 90 seconds.
Def Stan 00-970 Part 5 Sect 2.4 Sub Part D, Clauses UK25.803a – Emergency Evacuation.
UK25.803a requires that “Evacuation testing appropriate to role should include military-specific requirements, such as personnel wearing/carrying body amour, weapons and kit”.
Equipment Contribution to Residual Risk to Life (ECtRtL)
A potential ECtRtL has been identified as a result of the non-compliance. The potential ECtRtL could be created if increased time is required to evacuate the Air System due to the non-regulatory compliant aisle width.
ELoS
The TAA has decided that they can claim an ELoS and has submitted the following MCRI to the MAA.