[Federal Register Volume 65, Number 169 (Wednesday, August 30, 2000)]
[Proposed Rules]
[Pages 52677-52678]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-22123]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-265-AD]
RIN 2120-AA64


Airworthiness Directives; Lockheed Model 188A and 188C Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to all Lockheed Model 188A and 188C 
series airplanes. This proposal would require a revision of the 
Airplane Flight Manual (AFM) to add procedures for donning the 
flightcrew oxygen masks when the cabin altitude warning horn is 
activated. This action is intended to prevent incapacitation of the 
flightcrew as a result of lack of oxygen and consequent loss of control 
of the airplane due to absence of AFM procedures for donning the 
flightcrew oxygen masks when the cabin altitude warning horn is 
activated.

DATES: Comments must be received by October 16, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-265-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2000-NM-265-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.
    This information may be examined at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, 
Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix 
Boulevard, suite 450, Atlanta, Georgia 30349.

FOR FURTHER INFORMATION CONTACT: Thomas Peters, Aerospace Engineer, 
Systems and Flight Test Branch, ACE-116A, FAA, Atlanta Aircraft 
Certification Office, One Crown Center, 1895 Phoenix Boulevard, suite 
450, Atlanta, Georgia 30349; telephone (770) 703-6063 fax (770) 703-
6097.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Submit comments using the following format:
     Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
     For each issue, state what specific change to the proposed 
AD is being requested.
     Include justification (e.g., reasons or data) for each 
request.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2000-NM-265-AD.'' The postcard will be date stamped 
and returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 2000-NM-265-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On October 25, 1999, a Learjet Model 35 series airplane operating 
under part 135 of the Federal Aviation Regulations (14 CFR part 135) 
departed Orlando International Airport enroute to Dallas, Texas. Air 
traffic control lost communication with the airplane near Gainsville, 
Florida. Air Force and National Guard airplanes intercepted the 
airplane, but the flightcrews of the chase airplanes indicated that the 
windows of the Model 35 series airplane were apparently frosted over 
and prevented the chase airplane flightcrews from observing the 
interior of the Model 35 series airplane. The flightcrews of the chase 
airplanes reported that they did not observe any damage to the 
airplane. Subsequently, the Model 35 series airplane ran out of fuel 
and crashed in South Dakota. To date, causal factors of the accident 
have not been determined. However, lack of the Learjet flightcrew's 
response to air traffic control poses the possibility of flightcrew 
incapacitation and raises concerns with the pressurization and oxygen 
systems.
    Recognizing these concerns, the FAA initiated a special 
certification review (SCR) to determine if pressurization and oxygen 
systems on Model 35 series airplanes were certificated properly, and to 
determine if any unsafe design features exist in the pressurization and 
oxygen systems.
    The SCR team found that there have been several accidents and 
incidents that may have involved incapacitation of the flightcrews 
during flight. In one case, the airplane flightcrew did not activate 
the pressurization system or don their oxygen masks and the airplane 
flew in excess of 35,000 feet altitude. In another case, the airplane 
flightcrews did not don their oxygen masks when the cabin aural warning 
was activated. Further review by the SCR team indicates that the 
Airplane Flight Manual (AFM) of Learjet Model 35/36 series airplanes do 
not have an emergency procedure that requires donning the flightcrew 
oxygen masks when the cabin altitude aural warning is

[[Page 52678]]

activated. Additional review has found that the AFM's of Model 35A and 
36A series airplanes also do not contain appropriate flightcrew actions 
when the cabin altitude aural warning is activated. However, the AFM's 
do contain an abnormal procedure that allows the flightcrew to 
troubleshoot the pressurization system prior to donning the oxygen 
masks after the cabin altitude warning sounds. Troubleshooting may 
delay donning of the oxygen masks to the point that flightcrews may 
become incapable of donning their oxygen masks.
    The SCR findings indicated that the most likely cause for 
incapacitation was hypoxia (lack of oxygen). The only other plausible 
cause of incapacitation is exposure to toxic substances. However, no 
evidence was found to support the existence of toxic substances.
    Delayed response of the flightcrew in donning oxygen masks upon the 
activation of the cabin altitude warning horn could lead to 
incapacitation of the flightcrew and loss of control of the airplane.
    A review of the emergency procedures in the AFM for Lockheed Model 
188A and 188C series airplanes revealed that those AFM's also did not 
contain the requirement for the flightcrew to immediately don emergency 
oxygen masks. Therefore, all Lockheed Model 188A and 188C series 
airplanes may be subject to the same unsafe condition as described 
above.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require revising the Emergency Procedures Section of 
the AFM to provide the flightcrew with appropriate and timely actions 
in response to activation of the cabin altitude warning horn.

Cost Impact

    There are approximately 75 Model 188A and 188C series airplanes of 
the affected design in the worldwide fleet. The FAA estimates that 32 
airplanes of U.S. registry would be affected by this proposed AD, that 
it would take approximately 1 work hour per airplane to accomplish the 
proposed actions, and that the average labor rate is $60 per work hour. 
Based on these figures, the cost impact of the proposed AD on U.S. 
operators is estimated to be $1,920, or $60 per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the proposed requirements of 
this AD action, and that no operator would accomplish those actions in 
the future if this proposed AD were not adopted. The cost impact 
figures discussed in AD rulemaking actions represent only the time 
necessary to perform the specific actions actually required by the AD. 
These figures typically do not include incidental costs, such as the 
time required to gain access and close up, planning time, or time 
necessitated by other administrative actions.

Regulatory Impact

    The regulations proposed herein would not have a substantial direct 
effect 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, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    For the reasons discussed above, I certify that this proposed 
regulation (1) Is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, 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 copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:
Lockheed: Docket 2000-NM-265-AD.

    Applicability: All Model 188A and 188C series airplanes, 
certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent incapacitation of the flightcrew and consequent loss 
of control of the airplane due to delays in donning oxygen masks in 
response to the activation of the cabin altitude warning horn; 
accomplish the following:

Revision to the Airplane Flight Manual

    (a) Within 90 days after the effective date of this AD, revise 
the Emergency Procedures Section of the FAA-Approved Airplane Flight 
Manual (AFM) to include the following. This may be accomplished by 
inserting a copy of this AD in the AFM.

``Low Cabin Pressure Warning Light Comes On and Horn Starts Blowing

a. Oxygen Masks--Don. Select 100% oxygen.
b. If conditions dictate, initiate emergency descent.
c. Check cabin differential pressure gage.
    1. If differential pressure is below 13.34 + 0.30 in. Hg, lower 
cabin altitude selector wheel.
    2. If differential pressure is at 13.34 + 0.30 in. Hg, descend 
to lower aircraft altitude.

    Note: Warning horn can be silenced with cabin altitude warning 
horn switch.''

Alternative Methods of Compliance

    (b) 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, Atlanta Aircraft Certification 
Office (ACO), FAA. Operators shall submit their requests through an 
appropriate FAA Principal Maintenance Inspector, who may add 
comments and then send it to the Manager, Atlanta ACO.

    Note 1: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Atlanta ACO.

Special Flight Permit

    (c) Special flight permits may be issued in accordance with 
Secs. 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.

    Issued in Renton, Washington, on August 24, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-22123 Filed 8-29-00; 8:45 am]
BILLING CODE 4910-13-U