Class D to C Conversions: A review of cargo fire detection/suppression requirements

Class D to C Conversions

A review of cargo fire detection/suppression requirements

By Greg Napert

November 1999

Although the FAA has been addressing improving cargo compartments over the years, several incidents, along with public pressure following the May, 1996 incident involving the Class D compartment of a McDonnell Douglas DC-9 operated by Valujet Airlines, have pressured the FAA to force issue a requirement to upgrade Class D compartments to Class C.

According to the FAA, the Air Transport Association of America (ATA) followed on the heels of the Valujet accident by joining Vice President Gore, and formally announced that its membership would voluntarily install fire or smoke detection systems in Class D compartments. The ATA is a trade organization that represents the major US airlines. Details of the ATA plan — including an implementation schedule — were presented to FAA officials on January 31, 1997. The announcement, which affects approximately 2,700 airplanes operated by 21 ATA members, might appear to make the detection portion of this rulemaking moot; however, the FAA considers the installation of both detection and suppression systems in these compartments to be essential. As a result, the FAA published it's final rule on February 10, 1998.

The rule (14 CFR Parts 25 and 121 Revised Standards for Cargo or Baggage Compartments in Transport Category Airplanes; Final Rule) establishes a mandatory modification of the smoke detection and fire suppression characteristics of all Class D cargo compartments to that of either a Class C cargo compartment on passenger/combi aircraft, or Class E cargo compartment on cargo only aircraft (See Class distinction P. 52).
This mandate has a three-year compliance period, beginning March 19, 1998, and requires quarterly progress reports by operators during the three year implementation period.

What does this mean to you?
This upgrade involves installing detection and extinguishing systems.

Several companies have been working diligently over the last couple of years to develop STCs to upgrade these baggage compartments.

These STCs generally involve the installation of an extinguishing system — to include plumbing, nozzles, and fire bottles — and a separate detection system which typically includes smoke and/or heat detectors, and a cockpit mounted annunciator and control panel.

Several companies in the industry to include Barfield, Inc., Securaplane Technologies, and Walter-Kidde, have aggressively pursued Supplemental Type Certificates (STCs) since 1998 for the express purpose of addressing the D to C conversion. And although their systems include the two basic requirements — detection and suppression — that's where their similarities end.

Options for compliance
Components used in the systems being offered range from commercial detection units made by Cerberus, Kidde, and Hochiki to Halon extinguishers manufactured by companies like Kidde and Pacific Scientific Corporation.

The following are some examples of STCs that are available to the aviation community:

Barfield Inc.
Barfield has joined forces with Cerberus, Pacific Scientific HTL, Gables, ECS, and AAE (AAE engineered the system) to offer a complete turn-key installation for the D to C upgrade.