[Federal Register Volume 59, Number 125 (Thursday, June 30, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-15597]


[[Page Unknown]]

[Federal Register: June 30, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-NM-01-AD; Amendment 39-8955; AD 94-14-03]

 

Airworthiness Directives; Nordskog Water Heaters and Coffee 
Makers as Installed in Various Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Nordskog water heaters and coffee makers. This 
amendment requires an inspection to determine whether certain 
discrepant pressure relief valves have been installed in certain galley 
water heaters and coffee makers; and either replacement of the 
discrepant valves, or discontinued use of the water heaters or coffee 
makers and installation of placards indicating that these units are not 
to be used. This amendment is prompted by reports of injuries to cabin 
crew members that resulted from explosions of galley water heaters. The 
actions specified by this AD are intended to prevent explosions of 
galley water heaters and coffee makers, and subsequent injuries to 
passengers or cabin crew members.

DATES: Effective August 1, 1994.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of August 1, 1994.

ADDRESSES: The service information referenced in this AD may be 
obtained from Aircraft Products Company, 12807 Lake Drive, P.O. Box 
130, Delray Beach, Florida 33447-0130. This information may be examined 
at the Federal Aviation Administration (FAA), Transport Airplane 
Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; 
or at the FAA, Los Angeles Aircraft Certification Office (ACO), 3229 
East Spring Street, Long Beach, California; or at the Office of the 
Federal Register, 800 North Capitol Street, NW., suite 700, Washington, 
DC.

FOR FURTHER INFORMATION CONTACT: Walter Eierman, Systems and Equipment 
Branch, ANM-131L, FAA, Transport Airplane Directorate, Los Angeles ACO, 
3229 East Spring Street, Long Beach, California 90806-2425; telephone 
(310) 988-5336; fax (310) 988-5210.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to certain Nordskog water heaters and 
coffee makers was published in the Federal Register on March 16, 1994 
(59 FR 12203). That action proposed to require an inspection to 
determine whether certain discrepant pressure relief valves have been 
installed in certain galley water heaters and coffee makers; and either 
replacement of the discrepant valves, or discontinued use of the water 
heaters or coffee makers and installation of placards indicating that 
these units are not to be used.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    Several commenters support the proposal.
    Another commenter supports the proposed AD action, but requests 
that it be issued as an immediately adopted rule, in light of the 
potential for serious injury to passengers and cabin crew members that 
is associated with exploding water heaters and coffee makers. This 
commenter points out that AD 93-23-01, amendment 39-8735 (58 FR 61618, 
November 22, 1993), addressed this same problem in other water heaters 
and coffee makers using the same pressure relief valves, and it was 
made effective immediately, without prior opportunity for notice and 
public comment. This commenter questions whether the unsafe condition 
is any ``less'' for the units addressed by the proposal than for those 
addressed by AD 93-23-01. The FAA responds by noting that the incident 
reports that prompted the issuance of AD 93-23-01 involved units 
equipped with an integral check valve; AD 93-23-01 applies only to 
units with the integral check valve installation. At the time that AD 
93-23-01 was issued, the FAA was in the process of evaluating the need 
for additional AD action to address other installations that 
incorporate the same pressure relief valve design. The FAA found that 
Nordskog water heaters and coffee makers without the integral check 
valve could use the same pressure relief valve in other applications 
and, therefore, could also be subject to the same unsafe condition. 
However, because there had been no service history of incidents 
involving units without the integral check valve, the FAA could not 
demonstrate that the safety concern was so critical that it should 
preclude the opportunity for prior notice and public comment on this 
rule.
    Two commenters do not consider that AD action is appropriate to 
address a ``non-critical'' application of the subject valve. These 
commenters point out that AD 93-23-01 implemented the recommendations 
of Nordskog Service Bulletin 93-34, which targeted the ``critical'' 
valve installations. However, the proposed AD would implement the 
recommendations of Nordskog Service Bulletin 93-35, which addresses 
``non-critical'' installations of the valve. In light of this, the 
commenters contend that the AD is unnecessary. The FAA does not concur. 
The FAA acknowledges that AD 93-23-01 addresses units that incorporate 
the subject valve as an integral check valve, which may be viewed as a 
``critical'' application of the valve; it was a unit equipped with this 
integral check valve that exploded during the incident that prompted 
issuance of that AD. However, as discussed in the previous comment, the 
FAA has determined that water heaters and coffee makers that are not 
equipped with the integral check valve but use the same pressure relief 
valve addressed by AD 93-23-01, may also be subject to the same unsafe 
condition addressed by that AD. Although the commenters may view the 
component design of the units addressed by this AD action as ``less 
critical'' than those addressed by AD 93-23-01, the FAA has received no 
data to demonstrate that the subject relief valve is not necessary to 
assure system safety. Therefore, the FAA considers this AD action to be 
both appropriate and warranted.
    One commenter requests that the proposed rule be revised the permit 
the installation of the discrepant NUPRO pressure relief valve after 
the effective date of the AD and until the compliance time for 
inspection. This commenter points out that proposed paragraph (b) would 
require that, as of the effective date of the rule, no operator would 
be allowed to install a discrepant valve on any airplane; however, 
operators would have up to 12 months to remove any discrepant valve 
that is currently installed on the airplane. The FAA does not concur in 
this case. Removing an unsafe condition that already exists on an 
airplane necessarily involves performing maintenance on the airplane, 
and the FAA always provides some kind of ``grace period'' in order to 
minimize disruption of operations. On the other hand, prohibiting 
installation of spares that have been determined to create an unsafe 
condition does not require any additional maintenance activity; it 
simply requires use of one part rather than another. In general, once 
an unsafe condition has been determined to exist, it is the FAA's 
normal policy not to allow that condition to be introduced into the 
fleet. In developing the technical information on which every AD is 
based, one of the important considerations is the availability of parts 
that the AD will require to be installed. When it is determined that 
those (safe) parts are immediately available to operators, it is the 
FAA's policy to prohibit installation of the unsafe parts after the 
effective date of the AD.
    Further, the FAA considers that the period of time between 
publication of the final rule AD in the Federal Register and the 
effective date of the final rule (usually 30 days) is sufficient to 
provide operators with an opportunity to determine their immediate need 
for modified spares and to obtain them. Of course, in individual cases 
where this is not possible, every AD contains a provision that allows 
an operator to obtain an extension of compliance time based upon a 
specific showing of need. The FAA considers that this policy does 
increase safety and does not impose undue burdens on operators.
    One commenter is concerned about the thermostat installed on the 
water heaters and coffee makers equipped with the subject NUPRO 
pressure relief valves, and its involvement in the incident of 
explosion of the water heater. This commenter assumes that the incident 
was the result of one of two possible failure paths: Either the 
thermostat failed closed and the pressure relief valve failed closed; 
or the power relay failed closed and the pressure relief valve failed 
closed. This commenter indicates that the proposed rule does not 
address these possible failure paths or the fact that failures of the 
thermostat or relay are non-indicating by themselves. The FAA 
acknowledges that this commenter's assumptions about the failure paths 
is reasonable. Although a failure other than that of the relief valve 
could not be identified, some failure apparently occurred in the 
temperature control system to cause the pressure to build up beyond its 
normal level. Generally, it is expected that the temperature control 
system will fail sometime during its service life; the relief valve is 
in the system to address that failure. Although increased redundancy 
and failure monitoring in the temperature control system would be two 
ways of improving system safety, those methods are not considered 
necessary in this case. Replacement of the discrepant valve with the 
improved valve will address the failure scenario that actually 
occurred.
    This commenter also is concerned about part identification of 
inserts in the affected water heaters and coffee makers, and the need 
for a possible design change of NUPRO relief valves that have a common 
design type. Since these issues do not directly concern this rulemaking 
action, the FAA has passed the commenter's suggestions on to the 
appropriate manufacturer. -
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule as proposed.
    The FAA is aware that the subject water heaters and coffee makers 
are installed in various airplanes. There are approximately 300 of 
these airplanes in the worldwide fleet, the FAA estimates that 200 
airplanes are of U.S. registry. It will take approximately 2 work hours 
per airplane to accomplish the proposed actions, and the average labor 
rate is $55 per work hour. (There are approximately 4 water heaters 
and/or coffee makers installed on each airplane.) The cost of required 
parts is expected to be negligible. Based on these figures, the total 
cost impact of this AD on U.S. operators is estimated to be $22,000, or 
$110 per airplane.
    The total cost impact figure discussed above is based on 
assumptions that no operator has yet accomplished any of the 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted.
    The regulations adopted herein will not have substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, in 
accordance with Executive Order 12612, it is determined that this final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this action: (1) Is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) will not have a 
significant economic impact, positive or negative, on a substantial 
number of small entities under the criteria of the Regulatory 
Flexibility Act. A final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

94-14-03  Nordskog Industries, Inc.: Amendment 39-8955. Docket 94-
NM-01-AD.

    Applicability: Nordskog water heaters and coffee makers, as 
listed in Nordskog Industries, Inc., Service Bulletin SB-93-35, 
dated October 21, 1993; as installed in, but not limited to, Boeing 
Model 727, 737, 747, 757, and 767 series airplanes; McDonnell 
Douglas Model DC-9, DC-9-80, and DC-10 series airplanes, and MD-11 
airplanes; Lockheed Model L-1011 series airplanes; Airbus Industrie 
Model A300, A310, and A320 series airplanes; Gulfstream Model G-1159 
series airplanes and Model G-IV airplanes; de Havilland, Inc., Model 
DHC-8 series airplanes; Dassault-Aviation Model Mystere-Falcon 50, 
200, and 900 series airplanes; Canadair Model CL-600-1A11 (CL-600), 
CL-600-2A12 (CL-601), and CL-600-2B16 (CL-601-3A and -3R) and CL-
600-2B19 series airplanes; and Fokker Model F27 and F28 series 
airplanes; certificated in any category.
    To prevent explosions of galley water heaters and coffee makers, 
and subsequent injuries to passengers or cabin crew members, 
accomplish the following:
    (a) Within 12 months after the effective date of this AD, 
perform a one-time inspection to determine whether a NUPRO pressure 
relief valve having part number (P/N) SS-2C4-65 has been installed, 
in accordance with Nordskog Industries, Inc., Service Bulletin SB-
93-35, dated October 21, 1993. If any NUPRO pressure relief valve 
having P/N SS-2C4-65 has been installed, prior to further flight, 
accomplish either paragraph (a)(1) or (a)(2) of this AD.
    (1) Remove the NUPRO pressure relief valve having P/N SS-2C4-65 
and install a new, improved NUPRO pressure relief valve having P/N 
SS-CHF2-65, in accordance with the service bulletin. Or
    (2) Deactivate any Nordskog water heater or coffee maker listed 
in the service bulletin on which a NUPRO pressure relief valve 
having P/N SS-2C4-65 has been installed, and install a placard 
stating, ``Not to be used.''
    (b) As of the effective date of this AD, no person shall install 
a NUPRO pressure relief valve having P/N SS-2C4-65 on any airplane.
    (c) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Los Angeles Aircraft Certification 
Office (ACO), FAA, Transport Airplane Directorate. Operators shall 
submit their requests through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Los Angeles ACO.

    Note: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

    (d) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the airplane to a location where 
the requirements of this AD can be accomplished.
    (e) The inspection and installation shall be done in accordance 
with Nordskog Industries, Inc., Service Bulletin SB-93-35, dated 
October 21, 1993. This incorporation by reference was approved by 
the Director of the Federal Register in accordance with 5 U.S.C. 
552(a) and 1 CFR part 51. Copies may be obtained from Aircraft 
Products Company, 12807 Lake Drive, P.O. Box 130, Delray Beach, 
Florida 33447-0130. Copies may be inspected at the FAA, Transport 
Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or 
at the FAA, Los Angeles Aircraft Certification Office (ACO), 3229 
East Spring Street, Long Beach, California; or at the Office of the 
Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.
    (f) This amendment becomes effective on August 1, 1994.

    Issued in Renton, Washington, on June 22, 1994.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-15597 Filed 6-29 -94; 8:45 am]
BILLING CODE 4910-13-U