Document ID: FAA-2017-0522-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: Northrop Grumman LITEF GmbH LCR-100 Attitude and Heading Reference System Units
Posted Date: 2017-06-05T04:00Z

[Federal Register Volume 82, Number 106 (Monday, June 5, 2017)]
[Proposed Rules]
[Pages 25742-25744]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-11132]

 ========================================================================
 Proposed Rules
                                                 Federal Register
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 
 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
 ========================================================================
 

  Federal Register / Vol. 82, No. 106 / Monday, June 5, 2017 / Proposed 
Rules  

[[Page 25742]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0522; Directorate Identifier 2015-SW-068-AD]
RIN 2120-AA64

Airworthiness Directives; Northrop Grumman LITEF GmbH LCR-100 
Attitude and Heading Reference System Units

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
Northrop Grumman LITEF GmbH LCR-100 Attitude and Heading Reference 
System (AHRS) units installed on various aircraft. This proposed AD 
would require removing certain LCR-100 AHRS units from service. This 
proposed AD is prompted by test results showing loss of or invalid 
data. The proposed actions are intended to prevent an unsafe condition 
on these products.

DATES: We must receive comments on this proposed AD by August 4, 2017.

ADDRESSES: You may send comments by any of the following methods:
     Federal eRulemaking Docket: Go to http://www.regulations.gov. Follow the online instructions for sending your 
comments electronically.
     Fax: 202-493-2251.
     Mail: Send comments to the U.S. Department of 
Transportation, Docket Operations, M-30, West Building Ground Floor, 
Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590-0001.
     Hand Delivery: Deliver to the ``Mail'' address between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2017-
0522; or in person at the Docket Operations Office between 9 a.m. and 5 
p.m., Monday through Friday, except Federal holidays. The AD docket 
contains this proposed AD, the European Aviation Safety Agency (EASA) 
AD, the economic evaluation, any comments received, and other 
information. The street address for the Docket Operations Office 
(telephone 800-647-5527) is in the ADDRESSES section. Comments will be 
available in the AD docket shortly after receipt.
    For service information identified in this proposed rule, contact 
Northrop Grumman LITEF GmbH, Customer Service--Commercial Avionics, 
Loerracher Str. 18, 79115 Freiburg, Germany; telephone +49 (761) 4901-
142; fax +49 (761) 4901-773; email ahrs.support@ng-litef.de. You may 
review the referenced service information at the FAA, Office of the 
Regional Counsel, Southwest Region, 10101 Hillwood Pkwy, Room 6N-321, 
Fort Worth, TX 76177.

FOR FURTHER INFORMATION CONTACT: Nick Rediess, Aviation Safety 
Engineer, Boston Aircraft Certification Office, Engine & Propeller 
Directorate, 1200 District Avenue, Burlington, Massachusetts 01803; 
telephone (781) 238-7159; email nicholas.rediess@faa.gov.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to participate in this rulemaking by submitting 
written comments, data, or views. We also invite comments relating to 
the economic, environmental, energy, or federalism impacts that might 
result from adopting the proposals in this document. The most helpful 
comments reference a specific portion of the proposal, explain the 
reason for any recommended change, and include supporting data. To 
ensure the docket does not contain duplicate comments, commenters 
should send only one copy of written comments, or if comments are filed 
electronically, commenters should submit only one time.
    We will file in the docket all comments that we receive, as well as 
a report summarizing each substantive public contact with FAA personnel 
concerning this proposed rulemaking. Before acting on this proposal, we 
will consider all comments we receive on or before the closing date for 
comments. We will consider comments filed after the comment period has 
closed if it is possible to do so without incurring expense or delay. 
We may change this proposal in light of the comments we receive.

Discussion

    We propose to adopt a new AD for Northrop Grumman LITEF GmbH LCR-
100 AHRS units with a part number 145130-2000, 145130-2001, 145130-
7000, 145130-7001, or 145130-7100. These units are installed on various 
airplanes and helicopters and are often used to supply attitude and 
heading data to Primary Flight Displays (PFDs), autopilots, and other 
avionics. These units may be installed as part of a type-certificated 
design, an FAA supplemental type certificate, or a field approval. 
Northrop Grumman LITEF GmbH discovered the erroneous behavior of an 
AHRS unit during laboratory testing. The erroneous behavior occurs when 
the unit's continuous built-in test detects a failure and then does not 
correctly reset. When this occurs, the analog outputs of attitude and 
heading data freeze and the transmission of digital outputs of attitude 
and heading stops. The effect of the errors depends on how the AHRS 
unit outputs are used in a particular installation. For instance, if 
the AHRS unit analog outputs are used by a PFD without any automatic 
comparison with another source of data, the PFD will display misleading 
information, which could lead to loss of control of the aircraft. Other 
installations using the analog outputs might include an automatic 
comparison feature that detects and provides an alert if the attitude 
and heading data is frozen. A similar situation would occur in 
installations that use the digital outputs since the erroneous behavior 
would be detected. This proposed AD would only be applicable to 
installations of the AHRS units using analog outputs for the display of 
primary flight information or for input to an autopilot without 
automatic output comparison since these installations do not provide 
any warning indication of the erroneous behavior.

[[Page 25743]]

    EASA, which is the Technical Agent for the Member States of the 
European Union, has issued EASA AD No. 2015-0093, dated May 27, 2015, 
to correct an unsafe condition for certain part-numbered Northrop 
Grumman LITEF GmbH LCR-100 AHRS units. EASA states these units are 
known to be installed on, but not limited to, Pilatus PC-12, Learjet 
31A, Cessna 560XL, RUAG (Dornier) 228 series, and PZL Mielec M28 (Sky 
Truck) airplanes; and Bell Helicopter Textron, Inc., 412EP, Bell 
Helicopter Textron Canada 407, and Sikorsky S-76C helicopters. EASA 
advises that laboratory tests of the AHRS units discovered that when 
the built-in test detects failures and resets the system, the units are 
not executing the system reset properly. According to EASA, this 
results in a freeze of analog attitude and heading output data without 
detection or warning to the pilot. EASA states that installations vary, 
but if there is no automatic comparison of analog output to detect unit 
failure, this condition, if not corrected, could lead to undetected 
attitude and heading errors, possibly resulting in loss of control of 
the aircraft.
    This proposed AD would also affect AD 2010-26-09 (75 FR 81424, 
December 28, 2010), which applies to Sikorsky Model S-76A, B, and C 
helicopters with an AHRS unit P/N 145130-7100 installed. Since this 
proposed AD would require the removal of P/N 145130-7100, compliance 
with this AD would make AD 2010-26-09 no longer valid for those 
Sikorsky helicopters.

FAA's Determination

    We are proposing this AD because we evaluated all known relevant 
information and determined that an unsafe condition exists and is 
likely to exist or develop on other products of this same type design.

Related Service Information

    We reviewed Northrop Grumman LITEF GmbH Service Bulletin No. 
145130-0017-845, Revision D, dated April 1, 2015 (SB 145130-0017-845). 
SB 145130-0017-845 specifies returning the applicable part numbered 
AHRS units to certain repair stations for modification. The modified 
AHRS units, which have new part numbers, have an additional watchdog 
circuit in the electronic board that eliminates frozen analog outputs 
and digital output interruptions.

Proposed AD Requirements

    This proposed AD would require removing certain part-numbered LCR-
100 AHRS units that use analog outputs for primary flight information 
display or autopilot functions without automatic output comparison from 
service. This proposed AD would also prohibit installing those LCR-100 
AHRS units on any aircraft.

Differences Between This Proposed AD and the EASA AD

    This proposed AD would only apply to certain part-numbered AHRS 
units that use analog outputs for primary flight information display or 
autopilot functions without automatic output comparison. The EASA AD 
applies to all of these part-numbered units regardless of the type of 
installation. The EASA AD requires inserting a temporary revision into 
the flight manual for analog without automatic output comparison 
installations until the AHRS unit is replaced with a modified unit. 
This proposed AD would not require temporarily revising the flight 
manual. The EASA AD requires replacing the AHRS units with particular 
part-numbered modified units, while this proposed AD would require 
removing the AHRS units from service instead.

Costs of Compliance

    We estimate that this proposed AD would affect 50 aircraft of U.S. 
Registry. We estimate that operators may incur the following costs in 
order to comply with this AD. Labor costs are estimated at $85 per 
work-hour, and typical installations consist of two AHRS units. 
Replacing two AHRS units would take about 4 work-hours and $62,630 for 
required parts, for a total cost of $62,970 per aircraft and $3,148,500 
for the U.S. fleet.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. ``Subtitle VII: Aviation 
Programs,'' describes in more detail the scope of the Agency's 
authority.
    We are issuing this rulemaking under the authority described in 
``Subtitle VII, Part A, Subpart III, Section 44701: General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD 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.
    For the reasons discussed, I certify 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);
    3. Will not affect intrastate aviation in Alaska to the extent that 
it justifies making a regulatory distinction; and
    4. 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.
    We prepared an economic evaluation of the estimated costs to comply 
with this proposed AD and placed it in the AD docket.

List of Subjects in 14 CFR Part 39

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

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

Northrop Grumman LITEF GmbH LCR-100 Attitude and Heading Reference 
System: Docket No. FAA-2017-0522; Directorate Identifier 2015-SW-
068-AD.

(a) Applicability

    This AD applies to airplanes and helicopters, certificated in 
any category, with a Northrop Grumman LITEF GmbH LCR-100 Attitude 
and Heading Reference System (AHRS) unit part number (P/N) 145130-
2000, 145130-2001, 145130-7000, 145130-7001, or 145130-7100 
installed using analog outputs for primary flight information 
display or

[[Page 25744]]

autopilot functions without automatic output comparison. Aircraft 
known to have the subject AHRS units installed include but are not 
limited to the following:
    (1) Dornier Luftfahrt GmbH Model 228-100, 228-101, 228-200, 228-
201, 228-202, and 228-212 airplanes;
    (2) Learjet Inc. Model 31A airplanes;
    (3) Pilatus Aircraft Ltd. Model PC12, PC-12/45, and PC-12/47 
airplanes;
    (4) Polskie Zaklady Lotnicze Sp. z o.o. Model PZL M28 05 
airplanes;
    (5) Textron Aviation Inc. (type certificate previously held by 
Cessna Aircraft Company) Model 560XL airplanes;
    (6) Bell Helicopter Textron Canada Limited Model 407 
helicopters;
    (7) Bell Helicopter Textron Inc. Model 412 and 412EP 
helicopters; and
    (8) Sikorsky Aircraft Corporation Model S-76A, S-76-B, and S-76C 
helicopters.

(b) Unsafe Condition

    This AD defines the unsafe condition as the AHRS unit's analog 
outputs of attitude and heading data freezing without detection or 
warning. This condition could result in misleading attitude and 
heading information, anomalous autopilot behavior, and loss of 
control of the aircraft.

(c) Affected ADs

    This AD affects AD 2010-26-09, Amendment 39-16548 (75 FR 81424, 
December 28, 2010). Accomplishing a certain requirement of this AD 
terminates the requirements of AD 2010-26-09.

(d) Comments Due Date

    We must receive comments by August 4, 2017.

(e) Compliance

    You are responsible for performing each action required by this 
AD within the specified compliance time unless it has already been 
accomplished prior to that time.

(f) Required Actions

    (1) Within 25 hours time-in-service (TIS), remove the AHRS unit 
from service.
    (2) Removal from service of P/N 145130-7100 terminates the 
requirements of AD 2010-26-09 (75 FR 81424, December 28, 2010).
    (3) Do not install an AHRS unit P/N 145130-2000, 145130-2001, 
145130-7000, 145130-7001, or 145130-7100 on any aircraft.

(g) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Boston Aircraft Certification Office, FAA, may 
approve AMOCs for this AD. Send your proposal to: Nick Rediess, 
Aviation Safety Engineer, Boston Aircraft Certification Office, 
Engine & Propeller Directorate, 1200 District Avenue, Burlington, 
Massachusetts 01803; telephone (781) 238-7159; email 
nicholas.rediess@faa.gov.
    (2) For operations conducted under a 14 CFR part 119 operating 
certificate or under 14 CFR part 91, subpart K, we suggest that you 
notify your principal inspector, or lacking a principal inspector, 
the manager of the local flight standards district office or 
certificate holding district office before operating any aircraft 
complying with this AD through an AMOC.

(h) Additional Information

    (1) Northrop Grumman LITEF GmbH Service Bulletin No. 145130-
0017-845, Revision D, dated April 1, 2015, which is not incorporated 
by reference, contains additional information about the subject of 
this AD. For service information identified in this AD, contact 
Northrop Grumman LITEF GmbH, Customer Service--Commercial Avionics, 
Loerracher Str. 18, 79115 Freiburg, Germany; telephone +49 (761) 
4901-142; fax +49 (761) 4901-773; email ahrs.support@ng-litef.de. 
You may review the referenced service information at the FAA, Office 
of the Regional Counsel, Southwest Region, 10101 Hillwood Pkwy, Room 
6N-321, Fort Worth, TX 76177.
    (2) The subject of this AD is addressed in European Aviation 
Safety Agency (EASA) AD No. 2015-0093, dated May 27, 2015. You may 
view the EASA AD on the Internet at http://www.regulations.gov in 
the AD Docket.

(i) Subject

    Joint Aircraft Service Component (JASC) Code: 3420, Attitude and 
Directional Data System.

    Issued in Fort Worth, Texas, on May 19, 2017.
Scott A. Horn,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 2017-11132 Filed 6-2-17; 8:45 am]
BILLING CODE 4910-13-P