Federal Register / Vol. 81, No. 103 / Friday, May 27, 2016 / Proposed Rules 33609 

Qj = (Tj)(Pj) 

Where: 

Tj = Average time spent in failure condition 

j (in hours) 

Pj = Probability of occurrence of failure mode 

j (per hour) 

Note: If Pj is greater than 10¥3 per flight 

hour, then a 1.5 factor of safety must be 

applied to all limit load conditions specified 

in Subpart C. 

(iii) For residual strength 

substantiation, the rotorcraft must be 

able to withstand two-thirds of the 

ultimate loads defined in paragraph 

(c)(2)(ii) of these special conditions. 

(iv) If the loads induced by the failure 

condition have a significant effect on 

fatigue or damage tolerance, then their 

effects must be taken into account. 

(v) Freedom from flutter and 

divergence must be shown up to 1.11 

VNE (power on and power off). 

(vi) Freedom from flutter and 

divergence must also be shown up to 

1.11 VNE (power on and power off) for 

all probable system failure conditions 

combined with any damage required or 

considered under § 29.571(g) or 

§ 29.573(d)(3). 

(3) Consideration of certain failure 

conditions may be required by other 

sections of 14 CFR part 29 regardless of 

calculated system reliability. Where the 

failure analysis shows the probability of 

these failure conditions to be less than 

10¥9, criteria other than those specified 

in this paragraph may be used for 

structural substantiation to show 

continued safe flight and landing. 

(d) Failure indications. For system 

failure detection and indication, the 

following apply: 

(1) The system must be checked for 

failure conditions, not extremely 

improbable, that degrade the structural 

capability below the level required by 

14 CFR part 29 or that significantly 

reduce the reliability of the remaining 

operational portion of the system. As far 

as reasonably practicable, the flight 

crew must be made aware of these 

failures before flight. Certain elements 

of the control system, such as 

mechanical and hydraulic components, 

may use special periodic inspections, 

and electronic components may use 

daily checks, in lieu of detection and 

indication systems to achieve the 

objective of this requirement. These 

other means of detecting failures before 

flight will become part of the 

certification maintenance requirements 

(CMRs) and must be limited to 

components that are not readily 

detectable by normal detection and 

indication systems, and where service 

history shows that inspections will 

provide an adequate level of safety. 

(2) The existence of any failure 

condition, shown to be not extremely 

improbable, during flight that could 

significantly affect the structural 

capability of the rotorcraft and for 

which the associated reduction in 

airworthiness can be minimized by 

suitable flight limitations, must be 

signaled to the flight crew. For example, 

failure conditions that result in a factor 

of safety between the rotorcraft strength 

and the loads of Subpart C below 1.25, 

or flutter and divergence margins below 

1.11 VNE (power on and power off), 

must be signaled to the crew during 

flight. 

(e) Dispatch with known failure 

conditions. If the rotorcraft is to be 

dispatched in a known system failure 

condition that affects structural 

performance, or that affects the 

reliability of the remaining operational 

portion of the system to maintain 

structural performance, then the 

provisions of these special conditions 

must be met, including the provisions of 

paragraph (b) for the dispatched 

condition and paragraph (c) for 

subsequent failures. Expected 

operational limitations may be taken 

into account in establishing Pj as the 

probability of failure occurrence for 

determining the safety margin in Figure 

1 of these special conditions. Flight 

limitations and expected operational 

limitations may be taken into account in 

establishing Qj as the combined 

probability of being in the dispatched 

failure condition and the subsequent 

failure condition for the safety margins 

in Figure 2 of these special conditions. 

These limitations must be such that the 

probability of being in this combined 

failure state and then subsequently 

encountering limit load conditions is 

extremely improbable. No reduction in 

these safety margins is allowed if the 

subsequent system failure rate is greater 

than 10¥3 per hour. 

Issued in Fort Worth, Texas, on May 18, 

2016. 

Jorge Castillo, 

Acting Manager, Rotorcraft Directorate, 

Aircraft Certification Service. 

[FR Doc. 2016–12497 Filed 5–26–16; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2016–0733; Directorate 

Identifier 2015–SW–040–AD] 

RIN 2120–AA64 

Airworthiness Directives; Robinson 

Helicopter Company Helicopters 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: We propose to adopt a new 

airworthiness directive (AD) for 

Robinson Helicopter Company 

(Robinson) Model R44, R44 II, and R66 

helicopters. This proposed AD would 

require a visual inspection of the main 

rotor blade (MRB) and either removing 

or altering it. This proposed AD is 

prompted by a report that a fatigue crack 

was found at an MRB’s trailing edge and 

a determination that some MRBs may 

have reduced blade thickness due to 

blending out corrosion. The proposed 


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33610 Federal Register / Vol. 81, No. 103 / Friday, May 27, 2016 / Proposed Rules 

actions are intended to prevent an MRB 

fatigue crack, which could lead to MRB 

failure and subsequent loss of helicopter 

control. 

DATES: We must receive comments on 

this proposed AD by July 26, 2016. 

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–2016– 

0733, 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 

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 Robinson 

Helicopter Company, 2901 Airport 

Drive, Torrance, CA 90505; telephone 

(310) 539–0508; fax (310) 539–5198; or 

at http://www.robinsonheli.com. 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: Fred 

Guerin, Aviation Safety Engineer, Los 

Angeles Aircraft Certification Office, 

Transport Airplane Directorate, FAA, 

3960 Paramount Blvd., Lakewood, 

California 90712; telephone (562) 627– 

5232; email fred.guerin@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 

Robinson Model R44 and R44 II 

helicopters with an MRB part number 

(P/N) C016–7, Revisions N/C, A through 

Z, and AA through AE; and Model R66 

helicopters with an MRB P/N F016–2, 

Revisions A through E. The proposed 

AD would require a one-time inspection 

of the MRB for a crack, corrosion, dent, 

nick, or scratch, and either altering the 

MRB or removing it from service. 

On February 23, 2015, we issued 

Special Airworthiness Information 

Bulletin (SAIB) SW–15–08 for Robinson 

Model R44 and R44 II helicopters with 

part numbered C016–7 MRBs. SAIB 

SW–15–08 was prompted by a report of 

an in-flight failure of a MRB on a 

Robinson Model R44 II helicopter, 

which resulted in severe MRB vibration 

that prompted an emergency landing. 

SAIB SW–15–08 recommended daily 

pre-flight visual checks of the MRB 

trailing edge and having a qualified 

technician examine any damage before 

further flight. SAIB SW–15–08 also 

recommended, if unusual rotor system 

vibration was detected in flight, landing 

immediately and having a qualified 

mechanic examine the MRBs. 

After we issued SAIB SW–15–08, 

Robinson published R44 Service 

Bulletin SB–89, dated March 30, 2015 

(SB–89), and R66 Service Bulletin SB– 

13, dated March 30, 2015 (SB–13), 

recommending inspecting and 

modifying the MRB trailing edge. 

Therefore, on March 31, 2015, we 

revised the SAIB and issued SAIB SW– 

15–08R1 to advise that the MRB trailing 

edge has a corner where the blade chord 

begins to increase that can result in high 

stresses. SAIB SW–15–08R1 

recommends inspecting and modifying 

the MRB by following the actions in the 

service information. 

When the SAIBs were issued, we did 

not consider the reported incident to be 

an airworthiness concern that would 

warrant AD action. The FAA 

subsequently determined that some of 

the affected blades have been repaired 

by blending out corrosion in the area of 

the crack site radius, resulting in a 

reduced blade thickness. Also, reports 

to Robinson following the SB–89 and 

SB–13 inspections revealed corrosion 

remaining undetected between 

scheduled maintenance intervals. The 

presence of corrosion and a reduction in 

blade thickness could result in the 

development of a fatigue crack on the 

trailing edge at the transition radius 

before the MRB reaches its retirement 

life. Altering the MRB by smoothing the 

transition at the chord increase, as 

specified in SB–89 and SB–13, reduces 

the stress concentration and corrects 

this unsafe condition. The proposed 

actions are intended to prevent a fatigue 

crack, which could lead to failure of the 

MRB and subsequent loss of helicopter 

control. 

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 

these same type designs. 

Related Service Information Under 1 

CFR Part 51 

We reviewed SB–89 for Model R44 

and R44 II helicopters and SB–13 for 

Model R66 helicopters. SB–89 and SB– 

13 provide a one-time procedure to 

inspect each MRB for cracks, corrosion, 

and damage that may indicate a crack. 

If there is a crack, corrosion, or any 

damage, SB–89 and SB–13 specify 

removing the MRB from service and 

contacting Robinson. Otherwise, SB–89 

and SB–13 describe procedures to 

smooth the transition at the chord 

increase of each MRB to reduce the 

stress concentration. 

This service information is reasonably 

available because the interested parties 

have access to it through their normal 

course of business or by the means 

identified in the ADDRESSES section. 

Proposed AD Requirements 

This proposed AD would require 

within 100 hours time-in-service (TIS) 

or at the next annual inspection, 

whichever occurs first, cleaning the 

MRB and visually inspecting it for a 

crack, nick, corrosion, scratch, or dent. 


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Federal Register / Vol. 81, No. 103 / Friday, May 27, 2016 / Proposed Rules 33611 

If there is any crack, nick, corrosion, 

scratch or dent, this proposed AD would 

require repairing it or removing the 

MRB from service. If the MRB is 

repaired, or if there are no cracks, nicks, 

corrosion, scratches, or dents, this 

proposed AD would require altering the 

MRB. 

Differences Between This Proposed AD 

and the Service Information 

This proposed AD would require 

compliance within the next 100 hours 

TIS or at the next annual inspection, 

whichever occurs first. The service 

information recommends compliance 

within 15 hours TIS or by May 31, 2015, 

whichever occurs first, for the R44 and 

R44II helicopters and 10 hours TIS or by 

May 31, 2015, whichever occurs first, 

for the R66 helicopters. 

Costs of Compliance 

We estimate that this proposed AD 

would affect 2,236 helicopters of U.S. 

Registry and that labor costs average $85 

per work hour. Based on these 

estimates, we expect the following costs: 

• The visual inspection would 

require 1 work hour. No parts would be 

needed, so the cost per helicopter would 

total $85. The cost for the U.S. fleet 

would total $190,060. 

• Altering each MRB, if necessary, 

would require 2 work hours and $65 for 

parts. We estimate a total cost of $235 

per helicopter and $525,460 for the U.S. 

fleet. 

• Replacing a MRB, if necessary, 

would require 3 work hours. Parts 

would cost $19,900 for the Model R44 

and R44 II and $20,900 for the R66 

helicopter for a total cost of $20,155 and 

$21,155, respectively, per MRB. 

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 

■ 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 airworthiness 

directive (AD): 

Robinson Helicopter Company: Docket No. 

FAA–2016–0733; Directorate Identifier 

2015–SW–040–AD. 

(a) Applicability 

This AD applies to Robinson Helicopter 

Company (Robinson) Model R44 and R44 II 

helicopters with a main rotor blade (MRB) 

part number (P/N) C016–7 Revision N/C, A 

through Z, and AA through AE installed; and 

Model R66 helicopters with a MRB P/N 

F016–2 Revision A through E installed; 

certificated in any category. 

(b) Unsafe Condition 

This AD defines the unsafe condition as a 

fatigue crack on an MRB. This condition 

could result in failure of an MRB and loss of 

helicopter control. 

(c) Comments Due Date 

We must receive comments by July 26, 

2016. 

(d) 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. 

(e) Required Actions 

Within 100 hours time-in-service or at the 

next annual inspection, whichever occurs 

first: 

(1) Clean each MRB in the area depicted in 

Figure 1 of Robinson R44 Service Bulletin 

SB–89, dated March 30, 2015 (SB–89), or 

Robinson R66 Service Bulletin SB–13, dated 

March 30, 2015 (SB–13), as applicable to 

your model helicopter. 

(2) Using 10X or higher power 

magnification and a light, visually inspect 

the upper and lower MRB surfaces and 

trailing edge as depicted in Figure 1 of SB– 

89 or SB–13 for a crack, a nick, a scratch, a 

dent, or corrosion. If there is a crack, a nick, 

a scratch, a dent, or any corrosion, repair the 

MRB to an airworthy configuration if the 

damage is within the maximum repair 

damage limits or remove the MRB from 

service. 

(3) Alter the MRB in accordance with 

Compliance Procedure, paragraphs 4 through 

19, of SB–89 or SB–13, as applicable to your 

model helicopter. Equivalent tubing may be 

used for R7769–1 and R7769–6 tubes. Power 

tools may not be used for this procedure. 

(f) Alternative Methods of Compliance 

(AMOC) 

(1) The Manager, Los Angeles Aircraft 

Certification Office, FAA, may approve 

AMOCs for this AD. Send your proposal to: 

Fred Guerin, Aviation Safety Engineer, Los 

Angeles Aircraft Certification Office, 

Transport Airplane Directorate, FAA, 3960 

Paramount Blvd., Lakewood, California 

90712; telephone (562) 627–5232; email 9- 

ANM-LAACO-AMOC-REQUESTS@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. 

(g) Subject 

Joint Aircraft Service Component (JASC) 

Code: 6210, Main Rotor Blades. 

Issued in Fort Worth, Texas, on May 19, 

2016. 

Scott A. Horn, 

Acting Manager, Rotorcraft Directorate, 

Aircraft Certification Service. 

[FR Doc. 2016–12442 Filed 5–26–16; 8:45 am] 

BILLING CODE 4910–13–P 


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