59488 Federal Register / Vol. 73, No. 197 / Thursday, October 9, 2008 / Rules and Regulations 

of a door-mounted escape slide/raft located 

in the passenger compartment. We are 

issuing this AD to prevent injury to 

maintenance personnel, passengers, and crew 

during otherwise normal operating 

conditions and to prevent interference with 

evacuation of the airplane during an 

emergency, due to uncommanded inflation of 

a door-mounted escape slide/raft. 

Compliance 

(e) You are responsible for having the 

actions required by this AD performed within 

the compliance times specified, unless the 

actions have already been done. 

Restatement of Certain Requirements of AD 

2005–12–14 

Inspection for Excessive Tension on the 

Firing Cable 

(f) If any door-mounted escape slide/raft 

having any part number specified in 

paragraph (c) of this AD is installed: Within 

30 days after June 30, 2005 (the effective date 

of AD 2005–12–14), perform a tension check 

on the firing cable of the slide/raft, in 

accordance with Boeing Alert Service 

Bulletin 767–25A0390, dated May 13, 2005. 

If no excessive tension is detected, no further 

action is required by this AD, except for the 

requirements of paragraph (i) of this AD. 

Note 1: Boeing Alert Service Bulletin 767– 

25A0390, dated May 13, 2005, references 

Goodrich Alert Service Bulletin 5A3294/ 

5A3295–25A356, dated May 11, 2005, as an 

additional source of service information. 

Corrective Action for Excessive Tension on 

the Firing Cable 

(g) If any excessive tension of the firing 

cable is detected, before further flight, do the 

applicable corrective actions in accordance 

with the Boeing Alert Service Bulletin 767– 

25A0390, dated May 13, 2005. 

Previous Accomplishment 

(h) Inspections of the firing cables for 

excessive tension in accordance with Boeing 

Alert Service Bulletin 767–25A0390, dated 

May 13, 2005, that were accomplished before 

June 30, 2005, are acceptable for compliance 

with the requirements of paragraph (f) of this 

AD, provided that any applicable corrective 

action was completed. 

Parts Installation 

(i) As of June 30, 2005, no person may 

install on any airplane any Goodrich doormounted escape slide/raft having P/N 

5A3294–1, 5A3294–2, 5A3295–1, or 5A3295– 

3, unless the tension of the firing cable has 

been checked and the applicable corrective 

action completed in accordance with Boeing 

Alert Service Bulletin 767–25A0390, dated 

May 13, 2005, or the escape slide/raft has 

been repacked in accordance with Goodrich 

Packing Instructions, Evacuation Slide/Raft, 

Document 501636, Revision G, dated May 16, 

2005; Goodrich Packing Instructions, 

Evacuation Slide/Raft, LH, Document 

501637, Revision E, dated May 16, 2005; or 

Goodrich Packing Instructions, Evacuation 

Slide/Raft, RH, Document 501638, Revision 

D, dated May 16, 2005; as applicable. 

New Requirements of This AD 

Modification 

(j) Within 36 months after the effective date 

of this AD, do the applicable actions 

specified in paragraph (j)(1) or (j)(2) of this 

AD, by accomplishing all of the applicable 

actions specified in the Accomplishment 

Instructions of the Boeing Alert Service 

Bulletin 767–25A0395, Revision 1, dated 

January 25, 2007. 

(1) For Groups 1 and 2 airplanes as 

identified in the service bulletin: Review the 

airplane maintenance records to determine if 

Boeing Service Bulletin 767–25–0266 has 

been incorporated, or do a general visual 

inspection to determine if any door-mounted 

escape slide/raft having P/N 5A3294–1, 

5A3294–2, 5A3295–1, or 5A3295–3 is 

installed, and before further flight do all the 

applicable corrective actions. 

(2) For Groups 3, 4, 5, and 6 airplanes as 

identified in the service bulletin: Modify the 

escape slide/rafts. 

Note 2: Boeing Alert Service Bulletin 767– 

25A0395, Revision 1, refers to Goodrich 

Service Bulletin 5A3294/5A3295–25–362, 

dated July 25, 2006, as an additional source 

of service information for modifying a doormounted escape slide/raft. 

Alternative Methods of Compliance (AMOCs) 

(k)(1) The Manager, Seattle Aircraft 

Certification Office (ACO), FAA, ATTN: 

Keith Ladderud, Aerospace Engineer, Cabin 

Safety and Environmental Systems Branch, 

ANM–150S, FAA, Seattle ACO, 1601 Lind 

Avenue, SW., Renton, Washington 98057– 

3356; telephone (425) 917–6435; fax (425) 

917–6590; has the authority to approve 

AMOCs for this AD, if requested using the 

procedures found in 14 CFR 39.19. 

(2) To request a different method of 

compliance or a different compliance time 

for this AD, follow the procedures in 14 CFR 

39.19. Before using any approved AMOC on 

any airplane to which the AMOC applies, 

notify your appropriate principal inspector 

(PI) in the FAA Flight Standards District 

Office (FSDO), or lacking a PI, your local 

FSDO. 

(3) AMOCs approved previously in 

accordance with AD 2005–12–14 are 

approved as AMOCs for the corresponding 

provisions of paragraphs (f), (g), (h), (i), and 

(j) of this AD. 

Material Incorporated by Reference 

(l) You must use Boeing Alert Service 

Bulletin 767–25A0390, dated May 13, 2005; 

and Boeing Alert Service Bulletin 767– 

25A0395, Revision 1, dated January 25, 2007; 

as applicable; to perform the actions that are 

required by this AD, unless the AD specifies 

otherwise. 

(1) The Director of the Federal Register 

approved the incorporation by reference of 

Boeing Alert Service Bulletin 767–25A0395, 

Revision 1, dated January 25, 2007, in 

accordance with 5 U.S.C. 552(a) and 1 CFR 

part 51. 

(2) On June 30, 2005 (70 FR 34638, June 

15, 2005), the Director of the Federal Register 

approved the incorporation by reference of 

Boeing Alert Service Bulletin 767–25A0390, 

dated May 13, 2005. 

(3) Contact Boeing Commercial Airplanes, 

P.O. Box 3707, Seattle, Washington 98124– 

2207, for a copy of this service information. 

You may review copies at the FAA, 

Transport Airplane Directorate, 1601 Lind 

Avenue, SW., Renton, Washington; or at the 

National Archives and Records 

Administration (NARA). For information on 

the availability of this material at NARA, call 

202–741–6030, or go to: http:// 

www.archives.gov/federal-register/cfr/ibrlocations.html. 

Issued in Renton, Washington, on 

September 26, 2008. 

Michael Kaszycki, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service. 

[FR Doc. E8–23667 Filed 10–8–08; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2008–0147; Directorate 

Identifier 2007–NM–294–AD; Amendment 

39–15686; AD 2008–21–02] 

RIN 2120–AA64 

Airworthiness Directives; Boeing 

Model 737–600, –700, –700C, –800, and 

–900 Series Airplanes Equipped With 

CFM56–7 Engines 

AGENCY: Federal Aviation 

Administration (FAA), Department of 

Transportation (DOT). 

ACTION: Final rule. 

SUMMARY: The FAA is superseding an 

existing airworthiness directive (AD), 

which applies to certain Boeing Model 

737–600, –700, and –800 series 

airplanes. That AD currently requires 

repetitive inspections to detect damage 

of the aft strut insulation blanket, and 

eventual replacement of the insulation 

blankets with new, improved blankets. 

This new AD adds airplanes to the 

applicability and requires installation of 

a new heat insulation blanket and new 

cover plate on the left and right side 

engine struts. This new AD does not 

retain the requirements of the existing 

AD but does terminate the requirements 

of the existing AD. This AD results from 

reports of damaged heat insulation 

blankets on the engine struts. We are 

issuing this AD to prevent exposure of 

the lower surface of the strut to extreme 

high temperatures, consequent creation 

of a source of fuel ignition, and 

increased risk of an uncontrollable fire 

and possible fuel tank explosion. 

DATES: This AD becomes effective 

November 13, 2008. 

The Director of the Federal Register 

approved the incorporation by reference 


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of a certain publication listed in the AD 

as of November 13, 2008. 

ADDRESSES: For service information 

identified in this AD, contact Boeing 

Commercial Airplanes, P.O. Box 3707, 

Seattle, Washington 98124–2207. 

Examining the AD Docket 

You may examine the AD docket on 

the Internet at http:// 

www.regulations.gov; or in person at the 

Docket Management Facility between 9 

a.m. and 5 p.m., Monday through 

Friday, except Federal holidays. The AD 

docket contains this AD, the regulatory 

evaluation, any comments received, and 

other information. The address for the 

Docket Office (telephone 800–647–5527) 

is the Document Management Facility, 

U.S. Department of Transportation, 

Docket Operations, M–30, West 

Building Ground Floor, Room W12–140, 

1200 New Jersey Avenue, SE., 

Washington, DC 20590. 

FOR FURTHER INFORMATION CONTACT: 

Samuel Spitzer, Aerospace Engineer, 

Propulsion Branch, ANM–140S, FAA, 

Seattle Aircraft Certification Office, 

1601 Lind Avenue, SW., Renton, 

Washington 98057–3356; telephone 

(425) 917–6510; fax (425) 917–6590. 

SUPPLEMENTARY INFORMATION: 

Discussion 

The FAA issued a notice of proposed 

rulemaking (NPRM) to amend 14 CFR 

part 39 to include an AD that 

supersedes AD 99–04–11, amendment 

39–11035 (64 FR 6791, February 11, 

1999). The existing AD applies to 

certain Boeing Model 737–600, –700, 

and –800 series airplanes. That NPRM 

was published in the Federal Register 

on February 8, 2008 (73 FR 7484). That 

NPRM proposed to add airplanes to the 

applicability of the existing AD and 

require installation of a new heat 

insulation blanket and new cover plate 

on the left and right side engine struts, 

which would terminate the 

requirements of the existing AD. 

Comments 

We provided the public the 

opportunity to participate in the 

development of this AD. We have 

considered the comments that have 

been received on the NPRM. 

Support for the NPRM 

Boeing concurs with the contents of 

the NPRM. AirTran Airways (AirTran) 

and Continental Airlines (CAL) agree 

with the rule. 

Request To Delay AD Until Service 

Bulletin Is Revised 

CAL notes that Boeing has released 

Information Notice (IN) 737–54–1045 IN 

01, dated December 4, 2007. CAL notes 

that this IN states that Figures 2 and 4 

of Boeing Special Attention Service 

Bulletin 737–54–1045, dated July 25, 

2007, do not correctly illustrate the 

proper configuration of the insulation 

blanket. (We cited Boeing Special 

Attention Service Bulletin 737–54–1045 

in the NPRM as the appropriate source 

of service information.) Therefore, CAL 

requests that Boeing revise the service 

bulletin before we enact the AD. 

We disagree with waiting until Boeing 

revises its service bulletin before we 

issue the AD. We have determined that 

an unsafe condition exists and that the 

actions in this AD must be done to 

ensure continued safety. We do not 

consider that delaying this action until 

after the release of the manufacturer’s 

planned service bulletin is warranted 

since sufficient instructions currently 

exist to do the required replacement 

within the compliance time. Paragraph 

(h) of this AD provides operators the 

opportunity to request an extension of 

the compliance time if data are 

presented to justify the extension. 

However, we agree that the information 

in IN 737–54–1045 IN 01, which relates 

to the configuration of the insulation 

blanket, is important. Therefore, we 

have revised paragraph (f) of this AD to 

include the relevant information from 

the IN. 

Request To Identify Supplier Part 

Numbers (P/Ns) 

AirTran points out that P/N 

S315A213–57, as specified in paragraph 

(f) of the NPRM, is a specification 

number and that P/N 99A9257M is the 

supplier part number for the insulation 

blanket that is listed in the Boeing 

Model 737–700 Illustrated Parts Catalog. 

AirTran also points out a similar 

supplier part number exists for the 

insulation blankets that are prohibited 

from installation as specified in 

paragraph (g) of the NPRM. Therefore, 

AirTran requests that we identify both 

the Boeing specification number and the 

supplier part number in the AD. 

We disagree with the request to 

include supplier part numbers. The 

Boeing specification number (P/N) 

S315A213–57 is the high-level identifier 

for the part. This specification number 

is printed on each authorized vendor 

part that is made to Boeing 

specifications in accordance with the 

Boeing specification control document. 

Each authorized vendor can have a 

different part number. Therefore, using 

the specification P/N S315A213–57 

should prevent any confusion. We have 

not changed the AD in this regard. 

Request To Extend Compliance Time 

Air Transport Association (ATA), on 

behalf of its member American Airlines 

(AA), is concerned with the proposed 

60-month compliance period. The 

commenters note that the industry 

standard maintenance interval for the 

affected Boeing Model 737 airplanes is 

72 months. Therefore, a 60-month 

compliance period would unnecessarily 

increase out-of-service time and related 

costs. The commenters propose a 72- 

month compliance time, which would 

align more economically with industry 

standard maintenance review board 

(MRB) task intervals. 

We do not agree with the request to 

extend the compliance time. In 

developing an appropriate compliance 

time for this action, we considered the 

urgency associated with the subject 

unsafe condition, the availability of 

required parts, and the fact that the 

modification takes 4 work hours. 

According to the manufacturer, an 

ample number of required parts will be 

available to do the installation on the 

U.S. fleet within the proposed 

compliance time. In consideration of 

these items, we have determined that a 

60-month compliance time will ensure 

an acceptable level of safety. However, 

according to the provisions of paragraph 

(h) of this AD, we may approve requests 

to adjust the compliance time if the 

request includes data that prove that the 

new compliance time would provide an 

acceptable level of safety. We have not 

changed the AD in this regard. 

Request To Allow Additional Time for 

Parts Installation 

CAL notes that paragraph (g) of the 

NPRM states that operators may not 

install a heat insulation blanket, P/N 

S315A213–42 or –47, on any airplane 

after the effective date of the AD. CAL 

requests that operators be given an 

additional 60 days after the effective 

date of the AD to ensure ‘‘illegal’’ parts 

are purged from the inventory and 

Boeing is able to supply spare parts. 

We contacted CAL to obtain 

additional technical information in 

respect to this comment. CAL indicated 

that they initially had concerns over 

parts availability and long lead times to 

obtain P/N S315A213–57 heat 

insulation blankets. CAL stated that 

after checking with Boeing, parts 

availability and lead times are adequate 

and their comment is no longer relevant. 

We have not changed the AD in this 

regard. 

Conclusion 

We have carefully reviewed the 

available data, including the comments 


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59490 Federal Register / Vol. 73, No. 197 / Thursday, October 9, 2008 / Rules and Regulations 

that have been received, and determined 

that air safety and the public interest 

require adopting the AD with the 

change described previously. We have 

determined that this change will neither 

increase the economic burden on any 

operator nor increase the scope of the 

AD. 

Costs of Compliance 

There are about 2,148 airplanes of the 

affected design in the worldwide fleet. 

This AD affects about 740 airplanes of 

U.S. registry. The following table 

provides the estimated costs for U.S. 

operators to comply with this AD. The 

average labor rate is $80 per work hour. 

ESTIMATED COSTS

Action Work 

hours Parts Cost per airplane Fleet cost 

Installation (new action) ................................................................................................. 4 $4,730 $5,050 $3,737,000 

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 have determined that this AD will 

not have federalism implications under 

Executive Order 13132. This AD will 

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 that this AD: 

(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. 

We prepared a regulatory evaluation 

of the estimated costs to comply with 

this AD and placed it in the AD docket. 

See the ADDRESSES section for a location 

to examine the regulatory evaluation. 

List of Subjects in 14 CFR Part 39 

Air transportation, Aircraft, Aviation 

safety, Incorporation by reference, 

Safety. 

Adoption of the Amendment 

■ Accordingly, under the authority 

delegated to me by the Administrator, 

the FAA amends 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 Federal Aviation 

Administration (FAA) amends § 39.13 

by removing amendment 39–11035 (64 

FR 6791, February 11, 1999) and by 

adding the following new airworthiness 

directive (AD): 

2008–21–02 Boeing: Amendment 39–15686. 

Docket No. FAA–2008–0147; Directorate 

Identifier 2007–NM–294–AD. 

Effective Date 

(a) This AD becomes effective November 

13, 2008. 

Affected ADs 

(b) This AD supersedes AD 99–04–11. 

Applicability 

(c) This AD applies to Boeing Model 737– 

600, –700, –700C, –800, and –900 series 

airplanes, certificated in any category, as 

identified in Boeing Special Attention 

Service Bulletin 737–54–1045, dated July 25, 

2007. 

Unsafe Condition 

(d) This AD results from reports of 

damaged heat insulation blankets on the 

engine struts. We are issuing this AD to 

prevent exposure of the lower surface of the 

strut to extreme high temperatures, 

consequent creation of a source of fuel 

ignition, and increased risk of uncontrollable 

fire and possible fuel tank explosion. 

Compliance 

(e) You are responsible for having the 

actions required by this AD performed within 

the compliance times specified, unless the 

actions have already been done. 

Installation 

(f) Within 60 months after the effective 

date of this AD, install a new heat insulation 

blanket, part number (P/N) S315A213–57, 

and a new cover plate on the left and right 

side engine struts in accordance with the 

Accomplishment Instructions of Boeing 

Special Attention Service Bulletin 737–54– 

1045, dated July 25, 2007, except Figure 2 

and Figure 4 of the service bulletin should 

show four holes on the aft edge of the heat 

insulation blanket instead of two. Operators 

should also note that on installation of the 

heat insulation blanket, the two inner holes 

on the aft edge of the heat insulation blanket 

are not used or filled. 

Parts Installation 

(g) As of the effective date of this AD, no 

person may install a heat insulation blanket, 

P/N S315A213–42 or –47, on any airplane. 

Alternative Methods of Compliance 

(AMOCs) 

(h)(1) The Manager, Seattle Aircraft 

Certification Office (ACO), FAA, ATTN: 

Samuel Spitzer, Aerospace Engineer, 

Propulsion Branch, ANM–140S, FAA, Seattle 

ACO, 1601 Lind Avenue, SW., Renton, 

Washington 98057–3356; telephone (425) 

917–6510; fax (425) 917–6590; has the 

authority to approve AMOCs for this AD, if 

requested using the procedures found in 14 

CFR 39.19. 

(2) To request a different method of 

compliance or a different compliance time 

for this AD, follow the procedures in 14 CFR 

39.19. Before using any approved AMOC on 

any airplane to which the AMOC applies, 

notify your appropriate principal inspector 

(PI) in the FAA Flight Standards District 

Office (FSDO), or lacking a PI, your local 

FSDO. 

Material Incorporated by Reference 

(i) You must use Boeing Special Attention 

Service Bulletin 737–54–1045, dated July 25, 

2007, to perform the actions that are required 

by this AD, unless the AD specifies 

otherwise. The Director of the Federal 

Register approved the incorporation by 

reference of this document in accordance 

with 5 U.S.C. 552(a) and 1 CFR part 51. 

Contact Boeing Commercial Airplanes, P.O. 

Box 3707, Seattle, Washington 98124–2207, 

for a copy of this service information. You 

may review copies at the FAA, Transport 

Airplane Directorate, 1601 Lind Avenue, 


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Federal Register / Vol. 73, No. 197 / Thursday, October 9, 2008 / Rules and Regulations 59491 

SW., Renton, Washington; or at the National 

Archives and Records Administration 

(NARA). For information on the availability 

of this material at NARA, call 202–741–6030, 

or go to: http://www.archives.gov/federalregister/cfr/ibr-locations.html. 

Issued in Renton, Washington, on 

September 29, 2008. 

Ali Bahrami, 

Manager, Transport Airplane Directorate, 

Aircraft Certification Service. 

[FR Doc. E8–23573 Filed 10–8–08; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

(DOT) 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2008–1067; Directorate 

Identifier 2008–CE–052–AD; Amendment 

39–15688; AD 2008–21–04] 

RIN 2120–AA64 

Airworthiness Directives; Hawker 

Beechcraft Corporation Model 390 

Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule; request for 

comments. 

SUMMARY: The FAA is adopting a new 

airworthiness directive (AD) for certain 

Hawker Beechcraft Corporation Model 

390 airplanes. This AD requires you to 

modify the cabin barometric pressure 

switch and cabin altitude high switch 

installations and perform a functional 

test of the switches and related systems. 

This AD results from the possibility of 

barometric pressure switch electrical 

connections being incorrectly connected 

or inadvertently disconnected. We are 

issuing this AD to modify the cabin 

barometric pressure switch and cabin 

altitude high switch to prevent them 

from becoming incorrectly connected or 

inadvertently disconnected, which may 

result in no CABIN ALT HI 

annunciation in the cockpit and no 

automatic deployment of the cabin 

oxygen masks. This failure could lead to 

incapacitation of the crew due to 

hypoxia with possible inability to 

control the airplane. 

DATES: This AD becomes effective on 

October 20, 2008. 

On October 20, 2008, the Director of 

the Federal Register approved the 

incorporation by reference of certain 

publications listed in this AD. 

We must receive any comments on 

this AD by December 8, 2008. 

ADDRESSES: Use one of the following 

addresses to comment on this 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. 

To get the service information 

identified in this AD, contact Hawker 

Beechcraft Corporation, P.O. Box 85, 

Wichita, Kansas 67201–0085; telephone: 

(800) 429–5372 or (316) 676–3140; 

http://pubs.hawkerbeechcraft.com. 

To view the comments to this AD, go 

to http://www.regulations.gov. The 

docket number is FAA–2008–1067; 

Directorate Identifier 2008–CE–052–AD. 

FOR FURTHER INFORMATION CONTACT: Erik 

Brown, Aerospace Engineer, Wichita 

Aircraft Certification Office, 1801 

Airport Road, Room 100, Wichita, 

Kansas 67209; telephone: (316) 946– 

4132; fax: (316) 946–4107. 

SUPPLEMENTARY INFORMATION: 

Discussion 

We received reports of three 

occurrences of incorrectly connected 

barometric pressure switches on Hawker 

Beechcraft Corporation Model 390 

airplanes. This issue was discovered 

when an unannunciated cabin altitude 

high event occurred on one of the 

affected airplanes. Because the electrical 

connections of the barometric switches 

are identical, they have the potential of 

being incorrectly connected. Also, the 

wire cannot be positively secured to the 

switch, and it may become 

inadvertently disconnected. Either 

condition could cause loss of ability to 

annunciate a cabin altitude high 

condition. 

This condition, if not corrected, could 

result in no CABIN ALT HI 

annunciation in the cockpit and no 

automatic deployment of the cabin 

oxygen masks. This failure could lead to 

incapacitation of the crew due to 

hypoxia with possible inability to 

control the airplane. 

Relevant Service Information 

We reviewed Hawker Beechcraft 

Mandatory Service Bulletin SB 21–3899, 

issued: May 2008. The service 

information describes procedures for 

modifying the cabin barometric pressure 

switch and cabin altitude high switch 

installations and performing a 

functional test of the switches and 

related systems. 

FAA’s Determination and Requirements 

of this AD 

We are issuing this AD because we 

evaluated all the information and 

determined the unsafe condition 

described previously is likely to exist or 

develop on other products of the same 

type design. This AD requires you to 

modify the cabin barometric pressure 

switch and cabin altitude high switch 

installations and perform a functional 

test of the switches and related systems. 

FAA’s Determination of the Effective 

Date 

An unsafe condition exists that 

requires the immediate adoption of this 

AD. The FAA has found that the risk to 

the flying public justifies waiving notice 

and comment prior to adoption of this 

rule because occurrences of incorrectly 

connected barometric switches have 

been reported. Also, the terminal used 

on the switches may be inadvertently 

dislodged while performing airplane 

maintenance in the pedestal area. A 

potential consequence of an incorrectly 

connected or dislodged barometric 

switch is no CABIN ALT HI 

annunciation in the cockpit and no 

automatic deployment of the cabin 

oxygen masks. This failure could lead to 

incapacitation of the crew due to 

hypoxia with possible inability to 

control the airplane. Therefore, we 

determined that notice and opportunity 

for public comment before issuing this 

AD are impracticable and that good 

cause exists for making this amendment 

effective in fewer than 30 days. 

Comments Invited 

This AD is a final rule that involves 

requirements affecting flight safety, and 

we did not precede it by notice and an 

opportunity for public comment. We 

invite you to send any written relevant 

data, views, or arguments regarding this 

AD. Send your comments to an address 

listed under the ADDRESSES section. 

Include the docket number ‘‘FAA– 

2008–1067; Directorate Identifier 2008– 

CE–052–AD’’ at the beginning of your 

comments. We specifically invite 

comments on the overall regulatory, 

economic, environmental, and energy 

aspects of the AD. We will consider all 

comments received by the closing date 

and may amend the 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 


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