### 7998 Federal Register / Vol. 75, No. 35 / Tuesday, February 23, 2010 / Proposed Rules

(ii) Inspect the electrical connectors of the PPRV and replace the connectors if damaged, and install a vibration isolator, P/N 05–7212– K023801, to the gearbox assembly. Use paragraphs 1 through 27 of Thielert SB No. TM TAE 125–0020, Revision 1, dated November 25, 2009, to do the inspection and installation.
Repetitive PPRV Replacements

(4) Thereafter, within every 300 flight hours, replace the PPRV with a PPRV, P/N NM–0000–0124501 or P/N 05–7212– K021401.

FAA Differences

(f) We have found it necessary to not reference the second paragraph of the unsafe condition from the MCAI EASA AD 2009– 0224. That sentence stated that the problem has only manifested itself on those Thielert engines installed on Diamond Aircraft Industries DA 42 aircraft. The affected engines which require a PPRV could be used on other make and model airplanes in the future.

(g) We also did not reference the February 28, 2010 compliance date, which is in EASA AD 2009–0193R1, or the January 31, 2010 compliance date which is in EASA AD 2009–
0224. Alternative Methods of Compliance (AMOCs)

(h) The Manager, Engine Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19.

Related Information

(i) Refer to EASA AD 2009–0224, dated October 20, 2009 (TAE 125–02–99), and EASA AD 2009–0193R1, dated December 1, 2009 (TAE 125–01), for related information.

(j) Refer to Thielert SB No. TM TAE 125– 1007 P1, Revision 2, dated April 29, 2009, and Thielert SB No. TM TAE 125–1009 P1, Revision 3, dated October 14, 2009 (TAE 125–02–99), for related information.

(k) Refer to Thielert SB No. TM TAE 125– 0018, Revision 1, dated November 12, 2008, and Thielert SB No. TM TAE 125–0020, Revision 1, dated November 25, 2009 (TAE 125–01), for related information.

(l) Contact Thielert Aircraft Engines GmbH, Platanenstrasse 14 D–09350, Lichtenstein, Germany, telephone: +49–37204–696–0; fax: +49–37204–696–2912; e-mail: info@centurion-engines.com, for a copy of the service information referenced in this AD.

(m) Contact Tara Chaidez, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: tara.chaidez@faa.gov; telephone (781) 238–7773; fax (781) 238– 7199, for more information about this AD.

Issued in Burlington, Massachusetts, on February 16, 2010. Francis A. Favara, Manager, Engine and Propeller Directorate, Aircraft Certification Service.
[FR Doc. 2010–3484 Filed 2–22–10; 8:45 am]

**BILLING CODE 4910–13–P DEPARTMENT OF TRANSPORTATION** 

**Federal Aviation Administration**

**14 CFR Part 39**

**[Docket No. FAA–2009–0714; Directorate Identifier 2009–NM–041–AD]** 

**RIN 2120–AA64**

**Airworthiness Directives; Empresa Brasileira de Aeronautica S.A.**  **(EMBRAER) Model EMB–135 and –145, –145ER, –145MR, –145LR, –145XR,**  **–145MP, and –145EP Airplanes**

**AGENCY :**  Federal Aviation Administration (FAA), DOT.

**ACTION :**  Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.

**SUMMARY :**  We are revising an earlier NPRM for the products listed above. This action revises the earlier NPRM by expanding the scope. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

It was reported that after commanding the landing gear lever to down the three green landing gear positioning indication was displayed followed by the LG/LEVER DISAGREE EICAS [engine indicating and crew alerting system] message. The crew decided to continue the approach and landing procedure. As soon as the crew identified that the landing gear was not extended properly, a go-around procedure was successfully performed. During maneuver, the airplane settled momentarily onto the flaps and belly.
* * * * *

The unsafe condition is the landing gear remaining in the up and locked position during approach and landing. This condition could be accompanied by an invalid EICAS landing gear position indication, which could result in landing with gear in the up position and eliminate controllability of the airplane on the ground. This may consequently result in structural damage to the airplane. The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.

**DATES :**  We must receive comments on this proposed AD by March 22, 2010.

**ADDRESSES :**  You may send comments by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.

• Fax: (202) 493–2251. • Mail: U.S. Department of Transportation, Docket Operations, M– 30, West Building Ground Floor, Room W12–140, 1200 New Jersey Avenue, SE., Washington, DC 20590.

• Hand Delivery: U.S. Department of Transportation, Docket Operations, M– 30, West Building Ground Floor, Room W12–40, 1200 New Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this proposed AD, contact Empresa Brasileira de Aeronautica S.A. (EMBRAER), Technical Publications Section (PC 060), Av. Brigadeiro Faria Lima, 2170—Putim—12227–901 Sa  ̃ o Jose dos Campos—SP—BRASIL; telephone: +55 12 3927–5852 or +55 123309–0732; fax: +55 12 3927–7546; email: distrib@embraer.com.br; Internet: http://www.flyembraer.com. You may review copies of the referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425–227–1221
or 425–227–1152. Examining the AD Docket

You may examine the AD docket on the Internet at http:// www.regulations.gov; 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 regulatory 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 FURTHER INFORMATION CONTACT :**  Todd Thompson, Aerospace Engineer, International Branch, ANN–116, Transport Airplane Directorate, FAA, 1601 Lind Avenue, SW., Renton, Washington 98057–3356; telephone (425) 227–1175; fax (425) 227–1149.

**SUPPLEMENTARY INFORMATION :** 
Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the

**ADDRESSES** section. Include ‘‘Docket No. FAA–2009–0714; Directorate Identifier 2009–NM–041–AD ’’ at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the


### 7999 Federal Register / Vol. 75, No. 35 / Tuesday, February 23, 2010 / Proposed Rules

closing date and may amend this proposed AD based on those comments.

We will post all comments we receive, without change, to http:// www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD.

Discussion

We proposed to amend 14 CFR part 39 with an earlier NPRM for the specified products, which was published in the Federal Register on August 19, 2009 (74 FR 41810). That earlier NPRM proposed to require actions intended to address the unsafe condition for the products listed above.

Paragraph (c) of the original NPRM specifies that the AD applies to certain airplanes modified by certain Brazilian supplemental type certificates (STCs) and that are equipped with the affected part. Brazilian STCs do not apply to U.S. airplanes. The applicability of this supplemental NPRM would therefore not depend on accomplishment of the Brazilian STC. We have removed the reference to the Brazilian STCs from the applicability of this supplemental NPRM. We have coordinated this issue with Age ˆ ncia Nacional de Aviac

 ̧ a  ̃ o Civil (ANAC), which is the airworthiness authority for Brazil.

Relevant Service Information

We have reviewed EMBRAER Service Bulletin 145–32–0120, Revision 02, dated February 17, 2009. The original NPRM cited EMBRAER Service Bulletin 145–32–0120, Revision 01, dated November 4, 2008, as the appropriate source of service information for replacing the landing gear electronic unit (LGEU) with a new one having a new part number. EMBRAER Service Bulletin 145–32–0120, Revision 02, dated February 17, 2009, revises the effectivity but adds no new actions. We have revised paragraphs (g)(1) and (g)(3) (paragraphs (f)(1) and (f)(3) of the original NPRM) and Note 1 of this supplemental NPRM to refer to Revision 02. We have also added EMBRAER Service Bulletin 145–32–0120, Revision 01, dated November 4, 2008, to Table 1 of this supplemental NPRM to provide credit for actions done in accordance with EMBRAER Service Bulletin 145– 32–0120, Revision 01, dated November 4, 2008.

Comments

We have considered the following comments received on the original NPRM. Request To Include Installation of LGEU Having Part Number (P/N) 355–022–003 in the Aircraft Maintenance Manual

American Eagle Airlines requests that we revise the original NPRM to also allow replacing the LGEU, in accordance with Section 32–32–01 Part II of the EMBRAER Aircraft Maintenance Manual (AMM), as an acceptable method of compliance with the requirements of paragraph (g) of the original NPRM. Paragraph (g) of the original NPRM would have required replacing LGEU having P/N 355–022– 002 with P/N 355–002–003, in accordance with EMBRAER Service Bulletin 145–32–0120, Revision 01, dated November 4, 2008; or 145LEG– 32–0032, Revision 02, dated February 17, 2009; as applicable.

We disagree with the request. Section 32–32–01 of the EMBRAER AMM does not include all the actions specified in the Accomplishment Instructions of EMBRAER Service Bulletin 145–32– 0120, Revision 01, dated November 4, 2008; or 145LEG–32–0032, Revision 02, dated February 17, 2009. Neither the FAA nor the Brazilian authorities approve the AMM. However, operators may apply for an alternative method of compliance in accordance with the provisions specified in paragraph (h)(1) of this supplemental NPRM. No change has been made to this supplemental NPRM in this regard. Request To Revise Compliance Times

The Airline Pilots Association requests that we revise the compliance times to 12 months for replacing all LGEUs. The original NPRM specifies replacing LGEUs having P/N 355–022– 002 having serial numbers (S/Ns) 1000 through 1999 with new LGEUs having P/N 355–022–003 within 12 months after the effective date of the AD. It also specifies replacing LGEUs having P/N 355–022–002 having other serial numbers with new LGEUs having P/N 355–022–003 within 30 months after the effective date of this AD. The commenter provides no justification for this request.

We disagree with the request to revise the compliance times. All LGEUs identified in this AD have the potential to fail. However, according to the manufacturer’s data, LGEUs having P/N 1000 through 1999 have certain internal components that could fail sooner than the internal components of the other LGEUs. For this reason LGEUs having P/N 1000 through 1999 should be removed and replaced sooner than the other LGEUs. By replacing LGEUs having P/N 1000 through 1999 sooner as a result of a shorter compliance time, the same level of safety for all operators of the affected airplane is maintained. No change has been made to this supplemental NPRM in this regard. FAA’s Determination and Requirements of This Proposed AD

This product has been approved by the aviation authority of another country, and is approved for operation in the United States. Pursuant to our bilateral agreement with the State of Design Authority, we have been notified of the unsafe condition described in the MCAI and service information referenced above. We are proposing this AD because we evaluated all pertinent information and determined an unsafe condition exists and is likely to exist or develop on other products of the same type design.

Certain changes described above expand the scope of the earlier NPRM. As a result, we have determined that it is necessary to reopen the comment period to provide additional opportunity for the public to comment on this proposed AD.

Differences Between This AD and the MCAI or Service Information

We have reviewed the MCAI and related service information and, in general, agree with their substance. But we might have found it necessary to use different words from those in the MCAI to ensure the AD is clear for U.S. operators and is enforceable. In making these changes, we do not intend to differ substantively from the information provided in the MCAI and related service information.

We might also have proposed different actions in this AD from those in the MCAI in order to follow FAA policies. Any such differences are highlighted in a Note within the proposed AD. Explanation of Change to Costs of Compliance

Since issuance of the original NPRM, we have increased the labor rate used in the Costs of Compliance from $80 per work-hour to $85 per work-hour. The Costs of Compliance information, below, reflects this increase in the specified hourly labor rate. Costs of Compliance

Based on the service information, we estimate that this proposed AD would affect about 711 products of U.S. registry. We also estimate that it would take about 2 work-hours per product to comply with the basic requirements of this proposed AD. The average labor rate is $85 per work-hour. Required parts would cost about $0 per product.


### 8000 Federal Register / Vol. 75, No. 35 / Tuesday, February 23, 2010 / Proposed Rules

Where the service information lists required parts costs that are covered under warranty, we have assumed that there will be no charge for these costs. As we do not control warranty coverage for affected parties, some parties may incur costs higher than estimated here. Based on these figures, we estimate the cost of the proposed AD on U.S. operators to be $120,870, or $170 per product. 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 above, 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); 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.

We prepared a regulatory 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** 

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

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

**§ 39.13 [Amended]**

2. The FAA amends § 39.13 by adding the following new AD:
Empresa Brasileira de Aeronautica S.A. (EMBRAER): Docket No. FAA–2009– 0714; Directorate Identifier 2009–NM– 041–AD.

Comments Due Date

(a) We must receive comments by March 22, 2010.

Affected ADs

(b) None.
Applicability

(c) This AD applies to Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model EMB–135BJ, –135ER, –135KE, –135KL, –135LR, –145, –145ER, –145MR, –145LR, –145XR, –145MP, and –145EP airplanes; certificated in any category; equipped with landing gear electronic unit (LGEU) having part number (P/N) 355–022–002.
Subject

(d) Air Transport Association (ATA) of America Code 32: Landing gear.

Reason

(e) The mandatory continuing airworthiness information (MCAI) states:

It was reported that after commanding the landing gear lever to down the three green landing gear positioning indication was displayed followed by the LG/LEVER DISAGREE EICAS [engine indicating and crew alerting system] message. The crew decided to continue the approach and landing procedure. As soon as the crew identified that the landing gear was not extended properly, a go-around procedure was successfully performed. During maneuver, the airplane settled momentarily onto the flaps and belly.
* * * * * The unsafe condition is the landing gear remaining in the up and locked position during approach and landing. This condition could be accompanied by an invalid EICAS landing gear position indication, which could result in landing with gear in the up position and eliminate controllability of the airplane on the ground. This may consequently result in structural damage to the airplane. Required actions include replacing the LGEU with a new one having a new part number.
Compliance

(f) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Actions

(g) Unless already done, do the following actions:

(1) Within 12 months after the effective date of this AD, replace any LGEU having P/ N 355–022–002 having a serial number (S/N) 1000 through 1999 inclusive with a new LGEU having P/N 355–022–003, in accordance with the Accomplishment Instructions of EMBRAER Service Bulletin 145–32–0120, Revision 02, dated February 17, 2009; or 145LEG–32–0032, Revision 02, dated February 17, 2009; as applicable.

(2) As of 12 months after the effective date of this AD, no person may install on any airplane an LGEU having a P/N 355–022–002 having a S/N 1000 through 1999 inclusive.

(3) Within 30 months after the effective date of this AD, replace any LGEU having P/ N 355–022–002 having a serial number not identified in paragraph (g)(1) of this AD, with a new LGEU having P/N 355–022–003, in accordance with the Accomplishment Instructions of EMBRAER Service Bulletin 145–32–0120, Revision 02, dated February 17, 2009; or 145LEG–32–0032, Revision 02, dated February 17, 2009; as applicable.

(4) As of 30 months after the effective date of this AD, no person may install on any airplane an LGEU having a P/N 355–022–002 and a serial number not identified in paragraph (g)(1) of this AD.

(5) Replacing the LGEU is also acceptable for compliance with the requirements of paragraph (g) of this AD if done before the effective date of this AD in accordance with one of the service bulletins identified in Table 1 of this AD:



### TABLE 

### 1—C REDIT 

### S ERVICE 

### B ULLETINS

Embraer Service Bulletin— Revision— Dated—

145LEG–32–0032 .............................................. Original ........................................................... .. October 8, 2008. 145LEG–32–0032 .............................................. 01 ................................................................. ..... November 4, 2008. 145–32–0120 ..................................................... Original ....................................................... ...... September 15, 2008. 145–32–0120 ..................................................... 01 ............................................................. ......... November 4, 2008.


### 8001 Federal Register / Vol. 75, No. 35 / Tuesday, February 23, 2010 / Proposed Rules

FAA AD Differences

Note 1: This AD differs from the MCAI and/or service information as follows:

Although EMBRAER Service Bulletins 145LEG–32–0032, Revision 02, dated February 17, 2009; and 145–32–0120, Revision 02, dated February 17, 2009; specify that no person may install on any airplane an LGEU having P/N 355–022–002 as of 30 months after the effective date of this AD, we have determined that no LGEU having P/N 355–022–002 with a S/N 1000 through 1999 inclusive may be installed as of 12 months after the effective date of this AD. Allowing installation of those serial numbers beyond 12 months would not address the identified unsafe condition and ensure an adequate level of safety. This difference has been coordinated with the Age ˆ ncia Nacional de
Aviac

 ̧ a  ̃ o Civil (ANAC).

Other FAA AD Provisions

(h) The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs): The Manager, International Branch, ANM–116, Transport Airplane Directorate, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Todd Thompson, Aerospace Engineer, International Branch, ANM–116, Transport Airplane Directorate, FAA, 1601 Lind Avenue SW., Renton, Washington 98057–3356; telephone (425) 227–1175; fax (425) 227–1149. Before using any approved AMOC on any airplane to which the AMOC applies, notify your principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically reference this AD.

(2) Airworthy Product: For any requirement in this AD to obtain corrective actions from a manufacturer or other source, use these actions if they are FAA-approved.Corrective actions are considered FAAapproved if they are approved by the State of Design Authority (or their delegated agent). You are required to assure the product is airworthy before it is returned to service.

(3) Reporting Requirements: For any reporting requirement in this AD, under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq. ), the Office of Management and Budget (OMB) has approved the information collection requirements and has assigned OMB Control Number 2120–0056.

Related Information

(i) Refer to MCAI ANAC Airworthiness Directive 2009–01–01, effective January 8, 2009, as corrected by Brazilian Airworthiness Directive Errata, effective January 20, 2009; and Embraer Service Bulletins 145–32–0120, Revision 02, dated February 17, 2009; and 145LEG–32–0032, Revision 02, dated February 17, 2009; for related information. Issued in Renton, Washington, on February 16, 2010. Stephen P. Boyd, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 2010–3441 Filed 2–22–10; 8:45 am]

**BILLING CODE 4910–13–P**

**DEPARTMENT OF TRANSPORTATION**

**Federal Aviation Administration**

**14 CFR Part 39**

**[Docket No. FAA–2010–0158; Directorate Identifier 2010–CE–006–AD]** 

**RIN 2120–AA64**

**Airworthiness Directives; Hawker Beechcraft Corporation (Type**  **Certificate No. A00010WI Previously Held by Raytheon Aircraft Company)**  **Model 390 Airplanes**

**AGENCY :**  Federal Aviation Administration (FAA), Department of Transportation (DOT).

**ACTION :**  Notice of proposed rulemaking (NPRM).

**SUMMARY :**  We propose to adopt a new airworthiness directive (AD) for certain Hawker Beechcraft Corporation Model 390 airplanes. This proposed AD would require you to inspect the essential bus lightning strike protection for proper installation of metal oxide varistor (MOV) and spark gap wiring. This proposed AD would also require you to rework the wiring as necessary to achieve the required lightning strike/ surge protection. This proposed AD results from a report that the wires to the MOV and spark gap were swapped. We are proposing this AD to detect and correct improper installation of the MOV and spark gap wiring, which could result in overload of the MOV in a lightning strike and allow electrical energy to continue to the essential bus and disable equipment that receives power from the essential bus. The disabled equipment could include the autopilot, anti-skid system, hydraulic indicator, spoiler system, pilot primary flight display, audio panel, or the #1 air data computer. This failure could lead to a significant increase in pilot workload during adverse operating conditions.

**DATES :**  We must receive comments on this proposed AD by April 9, 2010.

**ADDRESSES :**  Use one of the following addresses to comment on this proposed AD:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments. • Fax: (202) 493–2251.

• Mail: U.S. Department of Transportation, Docket Operations, M– 30, West Building Ground Floor, Room W12–140, 1200 New Jersey Avenue, SE., Washington, DC 20590.

• Hand Delivery: U.S. Department of Transportation, Docket Operations, M– 30, West Building Ground Floor, Room W12–140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this proposed AD, contact Hawker Beechcraft Corporation, 9709 East Central, Wichita, Kansas 67201; telephone: (316) 676–5034; fax: (316) 676–6614; Internet: https:// www.hawkerbeechcraft.com/ service

_support/pubs/.

**FOR FURTHER INFORMATION CONTACT :**  Kevin Schwemmer, Aerospace Engineer, FAA, Wichita Aircraft Certification Office (ACO), 1801 Airport Road, Room 100, Wichita, Kansas 67209; telephone:(316) 946–4174; fax: (316) 946–4107; email: kevin.schwemmer@faa.gov.

**SUPPLEMENTARY INFORMATION :** 
Comments Invited

We invite you to send any written relevant data, views, or arguments regarding this proposed AD. Send your comments to an address listed under the

**ADDRESSES** section. Include the docket number, ‘‘FAA–2010–0158; Directorate Identifier 2010–CE–006–AD ’’ at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http:// www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive concerning this proposed AD.

Discussion

We received a report that on a Hawker Beechcraft Corporation Model 390 airplane the wires to the MOV and spark gap were swapped. The swapped wires were discovered during an inspection following a lightning strike. The spark gap has a higher current carrying capability than the MOV and is designed to carry direct currents caused by a lightning strike. In the event of a lightning strike, the potential exists to overload the MOV and allow an electrical spike to pass through to the essential bus.