[Federal Register Volume 63, Number 153 (Monday, August 10, 1998)]
[Notices]
[Pages 42655-42656]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-21300]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration


Aircraft Flight Recorder and Cockpit Voice Recorder

AGENCY: Federal Aviation Administration.

ACTION: Cancellation of Technical Standard Order (TSO) C123 and C124.

-----------------------------------------------------------------------

SUMMARY: This is a confirmation notice of cancellation of TSO-C123, 
Cockpit Voice Recorder System, and TSO-C124, Flight Data Recorder 
Systems. TSO-C123, prescribed the minimum performance standards for 
cockpit voice recorders that were required to be identified with 
marking ``TSO-C123.'' TSO-C124 prescribed the minimum performance 
standards for flight data recorder systems that were required to be 
identified with marking ``TSO-C124.'' This cancellation will ensure 
that future cockpit voice recorder systems and flight data recorder 
designs are produced under TSO-C123a, Cockpit Voice Recorder System, 
and TSO-C124a, Flight Data Recorder Systems, respectively.

EFFECTIVE DATE: August 2, 1998.

FOR FURTHER INFORMATION CONTACT: Mrs. Michelle Swearingen, Avionics 
Systems Branch, AIR-130, Aircraft Engineering Division, Aircraft 
Certification Service, Federal Aviation Administration, 800 
Independence Avenue, SW., Washington, DC 20591, FAX No. (202) 267-5340.

SUPPLEMENTARY INFORMATION: 

Background

    On September 26, 1996, the Federal Aviation Administration (FAA) 
published in the Federal Register a Notice, Volume 61, Page 50531, that 
canceled TSO-C123, Cockpit Voice Recorder Systems, and TSO-C124, Flight 
Data Recorder Systems and requested comments on the cancellations. TSO-
C123 prescribed the minimum performance standards for cockpit voice 
recorders that were required to be identified with marking ``TSO-
C123.'' TSO-C124 prescribed the minimum performance standards for 
flight data recorder systems that were required to be identified with 
marking ``TSO-C124.'' The cancellation will ensure that future cockpit 
voice recorder systems and flight data recorder designs are produced 
under TSO-C123a, Cockpit Voice Recorder System, dated 08/2/96, and TSO-
C124a, Flight Data Recorder Systems, dated 08/1/96, respectively.
    The National Transportation Safety Board reported that seven flight 
recorder media destroyed by postimpact fire in six accidents prompted 
concern about the adequacy of the performance standards for flight 
recorders. Minimum performance standards for impact and fire protection 
are outlined in four Technical Standard Orders (TSOs): TSO-C84 and TSO-
C123 addressed CVRs, and TSO-C51a and TSO-C124 addressed FDRs. TSO-C84 
and TSO-C51a were canceled May 18, 1996.
    The FAA Technical Center released a report on its study of flight 
recorder fire test requirements. The study determined that the high 
intensity, 30-minute fire test specified in the European Organisation 
for Civil Aviation Equipment (EUROCAE), ED-56A, ``Minimum Operational 
Requirements for Cockpit Voice Recorder System,'' and European 
Organisation for Civil Aviation Electronics (EUROCAE), ED-55, ``Minimum 
Operational Specification for Flight Data Recorder Systems,'' (and TSO-
C124) is not as severe as a 30-minute jet fuel pool fire that the test 
is intended to replicate. The Technical Center found that doubling

[[Page 42656]]

the exposure time from 30 to 60 minutes on the fire test produced a 
total heat that is equivalent to the heat experienced in a 30-minute 
postimpact jet fuel pool fire. The study also determined that flight 
records meeting the 10-hour low-intensity fire test conditions 
described in ED-36A would survive postimpact smoldering fires involving 
natural materials.
    The Safety Board recommended that the FAA should revise TSO-C123 
and TSO-C124 to reflect the findings of the FAA fire test study by (a) 
incorporating the long-term, low-intensity fire test requirements 
described in ED-56A, and (b) incorporating the high-intensity fire test 
requirements described in ED-55, and ED-56A, with the exception of 
extending the duration of the high-intensity fire test from 30 minutes, 
as specified in the EUROCAE documents, to 60 minutes. To improve the 
fire requirements for flight recorder certification and to upgrade the 
standards in the TSOs, the Board recommended that the FAA cancel the 
original TSO-C123 and TSO-C124 within 2 years after issuing the revised 
versions.
    The FAA received two comments in response to the Federal Register 
Notice canceling TSO-C123 and TSO-C124. The first commenter, Allied 
Signal Inc., expressed concern that canceling the TSOs would affect the 
approval status of ancillary equipment used with the recorders and 
produced under the canceled TSOs. The ancillary equipment approved 
under TSO-C123 and TSO-C124 meets the functional and environmental 
requirements of the TSOs, but it is not subject to the same crash 
protection requirements intended to preserve the recording medium. 
Accordingly, the subject ancillary equipment, i.e., associated control 
panels, microphones, speakers, underwater locators, etc., can continue 
to be approved and manufactured under TSO-C123 and TSO-C124 
authorizations as long as the applicable requirements of 14 CFR Part 21 
are met. Major design changes of this ancillary equipment will be 
approved under the latest TSOs. After the effective date of this 
cancellation, applicants for design approval of the primary recorders 
(black boxes) must comply with TSO-C123a and TSO-C124a.
    The second commenter, the Air Transportation Association (ATA), 
expressed concern that canceling the TSOs would require a supplemental 
type certificate or amended type certificate to retrofit equipment 
approved under the new TSOs. ATA feels that this additional 
certification activity would be particularly onerous for aircraft that 
are out of production. ATA suggests amending the language of the TSO to 
include the following statements:

    The intent of this TSO is to increase the recorder survivability 
over those manufactured under previous TSOs (C84, C123, C51a, or 
C124, as applicable) and is not meant to require further aircraft 
certification efforts. Units built to this new TSO can directly 
replace those built to the previous TSO(s) in certified 
installations without further certification activity.

    ATA is correct in its assertions that the intent of these TSOs is 
to increase recorder survivability, and it is not the FAA's intent to 
require STCs or amended type certificates to retrofit equipment 
produced under the new TSOs. Advisory Circular 20-41A, Substitute 
Technical Standard Order (TSO) Equipment, provides an acceptable means 
of compliance with the rules governing aircraft equipment installation 
in cases involving the substitution and installation of functionally 
similar TSO approved equipment. If it is determined that the equipment 
is a line replaceable unit, one that is similar in form, fit, and 
function and does not affect the aircraft's flight characteristics or 
flight controls, the substitution of that equipment will not require a 
supplemental or amended type certificate for installation. However, a 
grant of TSO approval is not a tacit grant of installation approval. 
The applicable requirements of 14 CFR Part 21, and of 14 CFR Part 43, 
Maintenance, Preventive Maintenance, Rebuilding, and Alteration, must 
still be met.
    Based on the finding of the NTSB and the FAA Technical Center 
study, TSO-C123 and TSO-C124 are canceled August 2, 1998. TSO-C123a, 
Cockpit Voice Recorder Systems, and TSO-C124a, Flight Data Recorder 
Systems were issued 8/2/96 and 8/1/96, respectively. TSO-C123a and TSO-
C124a incorporate the long-term, low-intensity fire test requirement, 
and the high-intensity fire test requirements, with the exception of 
extending the duration of the high-intensity fire test from 30 minutes 
to 60 minutes, as specified in the EUROCAE documents.

    Issued in Washington, DC, on July 31, 1998.
James C. Jones,
Manager, Aircraft Engineering Division, Aircraft Certification Service.
[FR Doc. 98-21300 Filed 8-7-98; 8:45 am]
BILLING CODE 4910-13-M