[Federal Register Volume 65, Number 38 (Friday, February 25, 2000)]
[Rules and Regulations]
[Pages 9996-9998]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-4484]


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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM168; Special Conditions No. 25-156-SC]


Special Conditions: McDonnell Douglas Model MD-10-10/10F and 
MD10-30/30F Airplanes; High Intensity Radiated Fields (HIRF).

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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

SUMMARY: These special conditions are issued for Model MD-10-10/10F and 
MD10-30/30F airplanes, manufactured by the McDonnell Douglas 
Corporation, now a wholly owned subsidiary of The Boeing Company. These 
airplanes will have novel and unusual design features when compared to 
the state of technology envisioned in the airworthiness standards for 
transport category airplanes. These airplanes will utilize electrical 
and electronic systems that perform critical functions. The applicable 
type certification regulations do not contain adequate or appropriate 
safety standards for the protection of this system from the effects of 
high-intensity radiated fields (HIRF). These special conditions contain 
the additional safety standards that the Administrator considers 
necessary to establish a level of safety equivalent to that provided by 
the existing airworthiness standards.

DATES: The effective date of these special conditions is February 15, 
2000. Comments must be received on or before March 27, 2000.

ADDRESSES: Comments on these special conditions may be mailed in 
duplicate to: Federal Aviation Administration, Transport Airplane 
Directorate, Attention: Rules Docket (ANM-114), Docket No. NM168, 1601 
Lind Avenue SW., Renton, Washington, 98055-4056; or delivered in 
duplicate to the Transport Airplane Directorate at the above address. 
Comments must be marked: Docket No. NM168. Comments may be inspected in 
the Rules Docket weekdays, except Federal holidays, between 7:30 a.m. 
and 4 p.m.

FOR FURTHER INFORMATION CONTACT: Gerry Lakin, FAA, Transport Airplane 
Directorate, Aircraft Certification Service, Standardization Branch, 
ANM-113, 1601 Lind Avenue SW., Renton, Washington, 98055-4056; 
telephone (425) 227-1187; facsimile (425) 227-1149.

SUPPLEMENTARY INFORMATION: The FAA has determined that notice and 
opportunity for prior public comment are impracticable because these 
procedures would significantly delay issuance of the approval design 
and thus delivery of the affected aircraft. In addition, the substance 
of these special conditions has been subject to the public comment 
process in several prior instances with no substantive comments 
received. The FAA therefore finds that good cause exists for making 
these special conditions effective upon issuance.

Comments Invited

    Interested persons are invited to submit such written data, views, 
or arguments, as they may desire. Communications should identify the 
regulatory docket and special conditions number and be submitted in 
duplicate to the address specified above. All communications received 
on or before the closing date for comments will be considered by the 
Administrator. These special conditions may be changed in light of the 
comments received. All comments received will be available in the Rules 
Docket for examination by interested persons, both before and after the 
closing date for comments. A report summarizing each substantive public 
contact with FAA personnel concerning this rulemaking will be filed in 
the docket. Persons wishing the FAA to acknowledge receipt of their 
comments submitted in response to this request must submit with those 
comments a self-addressed, stamped postcard on which the following 
statement is made: ``Comments to Docket No. NM168.'' The postcard will 
be date stamped and returned to the commenter.

Background

    On February 14, 1997, McDonnell Douglas Corporation (MDC) submitted 
an application to amend the DC-10/MD-11 Type Certificate No. A22WE to 
include four new models, MD-10-10/-10F and MD-10-30/-30F. The MD-10 
series aircraft are modified DC-10 aircraft with an Advanced Common 
Flightdeck (ACF), similar to that on the Model MD-11, that will allow 
operation with a two person flight crew. No changes to primary 
structures, engines, primary flight control systems, or aircraft 
performance are being made.
    The ACF on the MD-10 series aircraft will utilize electrical and 
electronic systems that perform critical functions; examples of which 
include the electronic displays and flight control computers. These 
systems can be susceptible to disruption to both command/response 
signals as a result of electrical and magnetic interference. This 
disruption of signals could result in loss of all critical functions 
that would prevent the continued safe flight and landing of the 
airplane.

Type Certification Basis

    Under the provisions of Sec. 21.101, The Boeing Company must show 
that the Model MD-10 series airplanes continue to meet the applicable 
provisions of the regulations incorporated by reference in Type 
Certificate No. A22WE, or the applicable regulations in effect on the 
date of application for the change to the Model MD-10 series aircraft. 
The regulations incorporated by reference in the type certificate are 
commonly referred to as the ``original type certification basis.'' 
Based on the application date, February 14, 1997, the applicable 
regulations are 14 CFR part 25, effective February 1, 1965, including 
amendments 25-1 through 25-89, for all areas affected by the change.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., part 25 as amended) do not contain adequate or 
appropriate safety standards for the Model MD-10 series aircraft 
because of novel or unusual design

[[Page 9997]]

features, special conditions are prescribed under the provisions of 
Sec. 21.16.
    Special conditions, as appropriate, are issued in accordance with 
Sec. 11.49, as required by Secs. 11.28 and 11.29(b), and become part of 
the type certification basis in accordance with Sec. 21.101(b)(2).
    Special conditions are initially applicable to the model for which 
they are issued. Should McDonnell Douglas Corporation, now a wholly 
owned subsidiary of The Boeing Company, apply at a later date for a 
change to the type certificate to include another model incorporating 
the same type certificate to incorporate the same novel or unusual 
design feature, these special conditions would apply to the other model 
as well under the provisions of Sec. 21.101(a)(1).

Novel or Unusual Design Features

    The ACF on the MD-10 series aircraft will utilize electrical and 
electronic systems that perform critical functions; examples of which 
include the electronic displays and flight control computers. These 
systems may be vulnerable to HIRF external to the airplane.

Discussion

    There is no specific regulation that addresses protection 
requirements for electrical and electronic systems from HIRF. Increased 
power levels from ground-based radio transmitters and the growing use 
of sensitive electrical and electronic systems to command and control 
airplanes have made it necessary to provide adequate protection.
    To ensure that a level of safety is achieved equivalent to that 
intended by the applicable regulations incorporated by reference, 
special conditions are needed for the Model MD-10 series aircraft, 
which require that new or significantly modified electrical and 
electronic systems, such as the electronic displays and flight control 
computers, that perform critical functions be designed and installed to 
preclude component damage and interruption of function due to both the 
direct and indirect effects of HIRF.

High-Intensity Radiated Fields (HIRF)

    With the trend toward increased power levels from ground-based 
transmitters, plus the advent of space and satellite communications 
coupled with electronic command and control of the airplane, the 
immunity of critical digital avionics systems to HIRF must be 
established.
    It is not possible to precisely define the HIRF to which the 
airplane will be exposed in service. There is also uncertainty 
concerning the effectiveness of airframe shielding for HIRF. 
Furthermore, coupling of electromagnetic energy to cockpit-installed 
equipment through the cockpit window apertures is undefined. Based on 
surveys and analysis of existing HIRF emitters, an adequate level of 
protection exists when compliance with the HIRF protection special 
conditions is shown with either paragraph 1 OR 2 below:
    1. A minimum threat of 100 volts rms per meter electric field 
strength from 10 KHz to 18 GHz.
    a. The threat must be applied to the system elements and their 
associated wiring harnesses without the benefit of airframe shielding.
    b. Demonstration of this level of protection is established through 
system tests and analysis.
    2. A threat external to the airframe of the following field 
strengths for the frequency ranges indicated.

------------------------------------------------------------------------
                                                           Frequency
           Field strength (volts per meter)           ------------------
                                                        Peak    Average
------------------------------------------------------------------------
10 kHz-100 kHz.......................................      50         50
100 kHz-500 kHz......................................      50         50
500 kHz-2 MHz........................................      50         50
2 MHz-30 MHz.........................................     100        100
30 MHz-70 MHz........................................      50         50
70 MHz-100 MHz.......................................      50         50
100 MHz-200 MHz......................................     100        100
200 MHz-400 MHz......................................     100        100
400 MHz-700 MHz......................................     700         50
700 MHz-1 GHz........................................     700        100
1 GHz-2 GHz..........................................    2000        200
2 GHz-4 GHz..........................................    3000        200
4 GHz-6 GHz..........................................    3000        200
6 GHz-8 GHz..........................................    1000        200
8 GHz-12 GHz.........................................    3000        300
12 GHz-18 GHz........................................    2000        200
18 GHz-40 GHz........................................     600       200
------------------------------------------------------------------------
The field strengths are expressed in terms of peak of the root-mean-
  square (rms) over the computer modulation period.

    The threat levels identified above are the result of an FAA review 
of existing studies on the subject of HIRF, in light of the ongoing 
work of the Electromagnetic Effects Harmonization Working Group of the 
Aviation Rulemaking Advisory Committee.

Applicability

    As discussed above, these special conditions are applicable to 
Model MD-10 series airplanes. Should McDonnell Douglas apply at a later 
date for a change to the type certificate to include another model 
incorporating the same novel or unusual design feature, these special 
conditions would apply to that model as well under the provisions of 
Sec. 21.101(a)(1).

Conclusion

    This action affects only certain design features on Model MD-10 
series airplanes. It is not a rule of general applicability and affects 
only the applicant who applied to the FAA for approval of these 
features on the airplane.
    The substance of the special conditions for these airplanes has 
been subjected to the notice and comment procedure in several prior 
instances and has been derived without substantive change from those 
previously issued. It is unlikely that prior public comment would 
result in a significant change from the substance contained herein. For 
this reason, and because a delay would significantly affect the 
certification of the airplane, which is imminent, the FAA has 
determined that prior public notice and comment are unnecessary and 
impracticable, and good cause exists for adopting these special 
conditions upon issuance. The FAA is requesting comments to allow 
interested persons to submit views that may not have been submitted in 
response to the prior opportunities for comment described above.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.


    The authority citation for these special conditions is as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.

The Special Conditions

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the following special conditions are issued as part of 
the type certification basis for the Model MD-10 series airplanes.
    1. Protection from Unwanted Effects of High-Intensity Radiated 
Fields (HIRF). Each electrical and electronic system that performs 
critical functions must be designed and installed to ensure that the 
operation and operational capability of these systems to perform 
critical functions are not adversely affected when the airplane is 
exposed to high-intensity radiated fields external to the airplane.
    2. For the purpose of these special conditions, the following 
definition applies:
    Critical Functions. Functions whose failure would contribute to or 
cause a failure condition that would prevent the continued safe flight 
and landing of the airplane.


[[Page 9998]]


    Issued in Renton, Washington, on February 15, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service, ANM-100.
[FR Doc. 00-4484 Filed 2-24-00; 8:45 am]
BILLING CODE 4910-13-P