18372 Federal Register / Vol. 72, No. 70 / Thursday, April 12, 2007 / Rules and Regulations 

period of time appropriate to the 

maneuvers. 

(4) It must always be possible to 

reduce incidence by conventional use of 

the controller. 

(5) The rate at which the airplane can 

be maneuvered from trim speeds 

associated with scheduled operating 

speeds, such as V2 and VREF, up to 

alpha-limit must not be unduly damped 

or significantly slower than can be 

achieved on conventionally controlled 

transport airplanes. 

g. Atmospheric Disturbances. 

Operation of the high incidence 

protection function must not adversely 

affect aircraft control during expected 

levels of atmospheric disturbances or 

impede the application of recovery 

procedures in case of windshear. 

Simulator tests and analysis may be 

used to evaluate such conditions but 

must be validated by limited flight 

testing to confirm handling qualities at 

critical loading conditions. 

h. [Reserved] 

i. Proof of Compliance. In addition to 

the requirements of § 25.21, the 

following special conditions apply: 

The flying qualities must be evaluated 

at the most unfavorable center of gravity 

position. 

j. Longitudinal Control: 

(1) In lieu of the requirements of 

§ 25.145(a) and (a)(1), the following 

special conditions apply: 

It must be possible—at any point 

between the trim speed for straight 

flight and Vmin—to pitch the nose 

downward, so that the acceleration to 

this selected trim speed is prompt, with: 

The airplane trimmed for straight 

flight at the speed achievable by the 

automatic trim system and at the most 

unfavorable center of gravity; 

(2) In lieu of the requirements of 

§ 25.145(b)(6), the following special 

conditions apply: 

With power off, flaps extended and 

the airplane trimmed at 1.3 VSR1, obtain 

and maintain airspeeds between Vmin

and either 1.6 VSR1 or VFE, whichever is 

lower. 

k. Airspeed Indicating System. (1) In 

lieu of the requirements of 

§ 25.1323(c)(1), the following special 

conditions apply: VMO to Vmin with the 

flaps retracted. 

(2) In lieu of the requirements of 

§ 25.1323(c)(2), the following special 

conditions apply: Vmin to VFE with flaps 

in the landing position. 

7. Flight Envelope Protection: Normal 

Load Factor (g) Limiting 

In addition to the requirements of 

§ 25.143(a)—and in the absence of other 

limiting factors—the following special 

conditions apply: 

a. The positive limiting load factor 

must not be less than: 

(1) 2.5g for the Electronic Flight 

Control System (EFCS) normal state. 

(2) 2.0g for the EFCS normal state 

with the high lift devices extended. 

b. The negative limiting load factor 

must be equal to or more negative than: 

(1) Minus 1.0g for the EFCS normal 

state. 

(2) 0.0g for the EFCS normal state 

with high lift devices extended. 

Note: This special condition does not 

impose an upper bound for the normal load 

factor limit, nor does it require that the limit 

exist. If the limit is set at a value beyond the 

structural design limit maneuvering load 

factor ‘‘n,’’ indicated in §§ 25.333(b) and 

25.337(b) and (c), there should be a very 

positive tactile feel built into the controller 

and obvious to the pilot that serves as a 

deterrent to inadvertently exceeding the 

structural limit. 

8. Flight Envelope Protection: Pitch, 

Roll, and High Speed Limiting 

Functions 

In addition to § 25.143, the following 

special conditions apply: 

a. Operation of the high speed limiter 

during all routine and descent 

procedure flight must not impede 

normal attainment of speeds up to the 

overspeed warning. 

b. The pitch limiting function must 

not impede airplane maneuvering, 

including an all-engines operating 

takeoff, for pitch angles up to the 

maximum required for normal 

operations plus a suitable margin in the 

pitch axis to allow for satisfactory speed 

control. 

c. The high speed limiting function 

must not impede normal attainment of 

speeds up to VMO/MMO during all 

routine and descent procedure flight 

conditions. 

d. The pitch and roll limiting 

functions must not restrict nor prevent 

attaining bank angles up to 65 degrees 

and pitch attitudes necessary for 

emergency maneuvering. Positive spiral 

stability, which is introduced above 35 

degrees bank angle, must not require 

excessive pilot strength on the side stick 

controller to achieve bank angles up to 

65 degrees. Stick force at bank angles 

greater than 35 degrees must not be so 

light that over-control would lead to 

pilot-induced oscillations. 

Issued in Renton, Washington, on April 4, 

2007. 

Stephen P. Boyd, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service. 

[FR Doc. E7–6888 Filed 4–11–07; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 25 

[Docket No. NM371; Special Conditions No. 

25–350–SC] 

Special Conditions: Dassault Aviation 

Model Falcon 7X Airplane; Sudden 

Engine Stoppage, Operation Without 

Normal Electrical Power, and Dive 

Speed Definition With Speed 

Protection System 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final special conditions. 

SUMMARY: These special conditions are 

issued for the Dassault Aviation Model 

Falcon 7X Airplane; Sudden Engine 

Stoppage, Operation Without Normal 

Electrical Power, and Dive Speed 

Definition with Speed Protection 

System. This airplane will have novel or 

unusual design features that include 

engine size and torque load, which 

affect sudden engine stoppage; electrical 

and electronic systems which perform 

critical functions, which affect 

operation without normal electrical 

power; and dive speed definition with 

speed protection system. These special 

conditions pertain to their effects on the 

structural performance of the airplane. 

The applicable airworthiness 

regulations do not contain adequate or 

appropriate safety standards for these 

design features. These special 

conditions contain the additional safety 

standards that the Administrator 

considers necessary to establish a level 

of safety equivalent to that established 

by the existing airworthiness standards. 

EFFECTIVE DATE: April 4, 2007. 

FOR FURTHER INFORMATION CONTACT: Tom 

Rodriguez, FAA, International Branch, 

ANM–116, Transport Airplane 

Directorate, Aircraft Certification 

Service, 1601 Lind Avenue, SW., 

Renton, Washington 98057–3356; 

telephone (425) 227–1503; facsimile 

(425) 227–1320. 

SUPPLEMENTARY INFORMATION: 

Background 

On June 4, 2002, Dassault Aviation, 9 

rond Point des Champs Elysees, 75008, 

Paris, France, applied for an FAA type 

certificate for its new Model Falcon 7X 

airplane. The Dassault Model Falcon 7X 

airplane is a 19 passenger transport 

category airplane powered by three aft 

mounted Pratt & Whitney PW307A high 

bypass ratio turbofan engines. 

Maximum takeoff weight will be 63,700 

pounds, and maximum certified altitude 


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Federal Register / Vol. 72, No. 70 / Thursday, April 12, 2007 / Rules and Regulations 18373 

will be 51,000 feet with a range of 5,700 

nautical miles. The airplane is operated 

using a fly-by-wire (FBW) primary flight 

control system. This will be the first 

application of a FBW primary flight 

control system in an airplane primarily 

intended for private/corporate use. 

The Dassault Aviation Model Falcon 

7X design incorporates equipment that 

was not envisioned when part 25 was 

created. This equipment affects sudden 

engine stoppage, operation without 

normal electrical power, and dive speed 

definition with speed protection system. 

Therefore, special conditions are 

required that provide the level of safety 

equivalent to that established by the 

regulations. 

Type Certification Basis 

Under the provisions of 14 CFR 21.17, 

Dassault Aviation must show that the 

Model Falcon 7X airplane meets the 

applicable provisions of 14 CFR part 25, 

as amended by Amendments 25–1 

through 25–108. 

If the Administrator finds that the 

applicable airworthiness regulations do 

not contain adequate or appropriate 

safety standards for the Model Falcon 

7X airplane because of novel or unusual 

design features, special conditions are 

prescribed under the provisions of 

§ 21.16. 

In addition to the applicable 

airworthiness regulations and special 

conditions, the Dassault Model Falcon 

7X airplane must comply with the fuel 

vent and exhaust emission requirements 

of 14 CFR part 34 and the noise 

certification requirements of 14 CFR 

part 36. 

The FAA issues special conditions, as 

defined in § 11.19, under § 11.38, and 

they become part of the type 

certification basis under § 21.17(a)(2). 

Special conditions are initially 

applicable to the model for which they 

are issued. Should the type certificate 

for that model be amended later to 

include any other model that 

incorporates the same novel or unusual 

design feature, the special conditions 

would also apply to the other model 

under § 21.101. 

Novel or Unusual Design Features 

The Dassault Aviation Model Falcon 

7X airplane will incorporate novel or 

unusual design features that will affect: 

• Sudden engine stoppage. 

• Operation without normal electrical 

power. 

• Dive speed definition with speed 

protection system. 

These special conditions address 

equipment which may affect the 

airplane’s structural performance, either 

directly or as a result of failure or 

malfunction. These special conditions 

are identical or nearly identical to those 

previously required for type 

certification of other airplane models. 

Discussion 

Because of these rapid improvements 

in airplane technology, the applicable 

airworthiness regulations do not contain 

adequate or appropriate safety standards 

for these design features. Therefore, in 

addition to the requirements of part 25, 

subparts C and D, the following special 

conditions apply. 

Special Conditions for Sudden Engine 

Stoppage 

The Dassault Model Falcon 7X will 

have high-bypass ratio turbofan engines. 

Engines of this size were not envisioned 

when § 25.361, pertaining to loads 

imposed by engine seizure, was adopted 

in 1965. Worst case engine seizure 

events become increasingly more severe 

with increasing engine size because of 

the higher inertia of the rotating 

components. 

Section 25.361(b)(1) requires that for 

turbine engine installations, the engine 

mounts and the supporting structures 

must be designed to withstand a ‘‘limit 

engine torque load imposed by sudden 

engine stoppage due to malfunction or 

structural failure.’’ Limit loads are 

expected to occur about once in the 

lifetime of any airplane. Section 25.305 

requires that supporting structures be 

able to support limit loads without 

detrimental permanent deformation, 

meaning that supporting structures 

should remain serviceable after a limit 

load event. 

Since adoption of § 25.361(b)(1), the 

size, configuration, and failure modes of 

jet engines have changed considerably. 

Current engines are much larger and are 

designed with large bypass fans. In the 

event of a structural failure, these 

engines are capable of producing much 

higher transient loads on the engine 

mounts and supporting structures. 

As a result, modern high bypass 

engines are subject to certain rare-butsevere engine seizure events. Service 

history shows that such events occur far 

less frequently than limit load events. 

Although it is important for the airplane 

to be able to support such rare loads 

safely without failure, it is unrealistic to 

expect that no permanent deformation 

will occur. 

Given this situation, the Aviation 

Rulemaking Advisory Committee 

(ARAC) proposed a design standard for 

today’s large engines. For the 

commonly-occurring deceleration 

events, the proposed standard requires 

engine mounts and structures to support 

maximum torques without detrimental 

permanent deformation. For the rarebut-severe engine seizure events such as 

loss of any fan, compressor, or turbine 

blade, the proposed standard requires 

engine mounts and structures to support 

maximum torques without failure, but 

allows for some deformation in the 

structure. 

The FAA concludes that modern large 

engines, including those on the Model 

Falcon 7X, are novel and unusual 

compared to those envisioned when 

§ 25.361(b)(1) was adopted and thus 

warrant a special condition. The special 

condition contains design criteria 

recommended by ARAC. The ARAC 

proposal was to revise the wording of 

§ 25.361(b), including §§ 25.361(b)(1) 

and (b)(2), removing language pertaining 

to structural failures and moving it to a 

separate requirement that discusses the 

reduced factors of safety that apply to 

these failures. 

Special Conditions for Operation 

Without Normal Electrical Power 

The Dassault Aviation Model Falcon 

7X airplane will have electrical and 

electronic systems which perform 

critical functions. The Model Falcon 7X 

airplane is a fly-by-wire control system 

that requires a continuous source of 

electrical power for the flight control 

system to remain operable, since the 

loss of all electrical power may be 

catastrophic to the airplane. The 

airworthiness standards of part 25 do 

not contain adequate or appropriate 

standards for the protection of the 

Electronic Flight Control System from 

the adverse effects of operations without 

normal electrical power. 

Section 25.1351(d), ‘‘Operation 

without normal electrical power,’’

requires safe operation in visual flight 

rule (VFR) conditions for at least five 

minutes with inoperative normal power. 

This rule was structured around a 

traditional design utilizing mechanical 

control cables for flight control surfaces 

and the pilot controls. Such traditional 

designs enable the flightcrew to 

maintain control of the airplane, while 

providing time to sort out the electrical 

failure, re-start the engines if necessary, 

and re-establish some of the electrical 

power generation capability. 

The Dassault Aviation Model Falcon 

7X airplane, however, will utilize an 

Electronic Flight Control System for the 

pitch and yaw control (elevator, 

stabilizer, and rudder). There is no 

mechanical linkage between the pilot 

controls and these flight control 

surfaces. Pilot control inputs are 

converted to electrical signals, which 

are processed and then transmitted via 

wires to the control surface actuators. At 

the control surface actuators, the 


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electrical signals are converted to an 

actuator command, which moves the 

control surface. 

To maintain the same level of safety 

as that associated with traditional 

designs, the Dassault Model 7X 

airplanes with electronic flight controls 

must not be time limited in their 

operation, including being without the 

normal source of electrical power 

generated by the engine or the Auxiliary 

Power Unit (APU) generated electrical 

power. 

Service experience has shown that the 

loss of all electrical power generated by 

the airplane’s engine generators or APU 

is not extremely improbable. Thus, it 

must be demonstrated that the airplane 

can continue safe flight and landing—

including steering and braking on 

ground for airplanes using steer/brakeby-wire—after total loss of normal 

electrical power with the use of its 

emergency electrical power systems. 

These emergency electrical power 

systems must be able to power loads 

that are essential for continued safe 

flight and landing. 

Special Conditions for Dive Speed 

Definition With Speed Protection 

System 

Dassault Aviation proposed to reduce 

the speed margin between VC and VD

required by § 25.335(b), based on the 

incorporation of a high speed protection 

system in the Model Falcon 7X flight 

control laws. The Falcon 7X is equipped 

with a high speed protection system 

which limits nose down pilot authority 

at speeds above VC/MC and prevents the 

airplane from actually performing the 

maneuver required under § 25.335(b)(1). 

Section 25.335(b)(1) is an analytical 

envelope condition which was 

originally adopted in Part 4b of the Civil 

Air Regulations to provide an acceptable 

speed margin between design cruise 

speed and design dive speed. Freedom 

from flutter and airframe design loads is 

affected by the design dive speed. While 

the initial condition for the upset 

specified in the rule is 1g level flight, 

protection is afforded for other 

inadvertent overspeed conditions as 

well. Section 25.335(b)(1) is intended as 

a conservative enveloping condition for 

all potential overspeed conditions, 

including non-symmetric ones. 

To establish that all potential 

overspeed conditions are enveloped, the 

applicant will demonstrate that the dive 

speed will not be exceeded during pilotinduced or gust-induced upsets in nonsymmetric attitudes. 

In addition, the high speed protection 

system in the Falcon 7X must have a 

high level of reliability. 

Discussion of Comments 

Notice of proposed special conditions 

No. 25–07–07–SC for the Dassault 

Aviation Model Falcon 7X airplanes 

was published in the Federal Register 

on March 1, 2007 (72 FR 9273). No 

comments were received, and the 

special conditions are adopted as 

proposed. 

Applicability 

As discussed above, these special 

conditions are applicable to the Dassault 

Aviation Model Falcon 7X airplane. 

Should Dassault Aviation apply at a 

later date for a change to the type 

certificate to include another model on 

the same type certificate incorporating 

the same novel or unusual design 

features, these special conditions would 

apply to that model as well. 

For Final Special Conditions Effective 

Upon Issuance 

Under standard practice, the effective 

date of final special conditions would 

be 30 days after the date of publication 

in the Federal Register; however, as the 

certification date for the Dassault Model 

Falcon 7X is imminent, the FAA finds 

that good cause exists to make these 

special conditions effective upon 

issuance. 

Conclusion 

This action affects only certain novel 

or unusual design features on model 

Falcon 7X airplanes. It is not a rule of 

general applicability. 

List of Subjects in 14 CFR Part 25 

Aircraft, Aviation safety, Reporting 

and recordkeeping requirements. 

The authority citation for these 

special conditions is as follows: 

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

44702, 44704. 

The Special Conditions 

Accordingly, pursuant to the 

authority delegated to me by the 

Administrator, the following special 

conditions are issued as part of the type 

certification basis for Dassault Aviation 

Model Falcon 7X airplanes. 

1. Sudden Engine Stoppage 

In lieu of the requirements of 

§ 25.361(b) the following special 

condition applies: 

(a) For turbine engine installations, 

the engine mounts, pylons and adjacent 

supporting airframe structure must be 

designed to withstand 1 g level flight 

loads acting simultaneously with the 

maximum limit torque loads imposed 

by each of the following: 

(1) Sudden engine deceleration due to 

a malfunction which could result in a 

temporary loss of power or thrust; and 

(2) The maximum acceleration of the 

engine. 

(b) For auxiliary power unit 

installations, the power unit mounts 

and adjacent supporting airframe 

structure must be designed to withstand 

1 g level flight loads acting 

simultaneously with the maximum limit 

torque loads imposed by each of the 

following: 

(1) Sudden auxiliary power unit 

deceleration due to malfunction or 

structural failure; and 

(2) The maximum acceleration of the 

power unit. 

(c) For engine supporting structures, 

an ultimate loading condition must be 

considered that combines 1 g flight 

loads with the transient dynamic loads 

resulting from: 

(1) The loss of any fan, compressor, or 

turbine blade; and separately 

(2) where applicable to a specific 

engine design, any other engine 

structural failure that results in higher 

loads. 

(d) The ultimate loads developed from 

the conditions specified in paragraphs 

(c)(1) and (2) above are to be multiplied 

by a factor of 1.0 when applied to 

engine mounts and pylons and 

multiplied by a factor of 1.25 when 

applied to adjacent supporting airframe 

structure. In addition, the airplane must 

be capable of continued safe flight 

considering the aerodynamic effects on 

controllability due to any permanent 

deformation that results from the 

conditions specified in paragraph (c), 

above. 

2. Operation Without Normal Electrical 

Power 

In lieu of the requirements of 14 CFR 

25.1351(d), the following special 

condition applies: 

It must be demonstrated by test or 

combination of test and analysis that the 

airplane can continue safe flight and 

landing with inoperative normal engine 

and APU generator electrical power (i.e., 

electrical power sources, excluding the 

battery and any other standby electrical 

sources). The airplane operation should 

be considered at the critical phase of 

flight and include the ability to restart 

the engines and maintain flight for the 

maximum diversion time capability 

being certified. 

3. Dive Speed Definition With Speed 

Protection System 

In lieu of the requirements of 

§ 25.335(b)(1)—if the flight control 

system includes functions which act 

automatically to initiate recovery before 


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the end of the 20 second period 

specified in § 25.335(b)(1)—the 

following special condition applies. 

The greater of the speeds resulting 

from the conditions of paragraphs (a) 

and (b), below, must be used. 

(a) From an initial condition of 

stabilized flight at VC/MC, the airplane 

is upset so as to take up a new flight 

path 7.5 degrees below the initial path. 

Control application, up to full authority, 

is made to try and maintain this new 

flight path. Twenty seconds after 

initiating the upset, manual recovery is 

made at a load factor of 1.5 g (0.5 

acceleration increment) or such greater 

load factor that is automatically applied 

by the system with the pilot’s pitch 

control neutral. The speed increase 

occurring in this maneuver may be 

calculated, if reliable or conservative 

aerodynamic data is used. Power, as 

specified in § 25.175(b)(1)(iv), is 

assumed until recovery is made, at 

which time power reduction and the use 

of pilot controlled drag devices may be 

used. 

(b) From a speed below VC/MC with 

power to maintain stabilized level flight 

at this speed, the airplane is upset so as 

to accelerate through VC/MC at a flight 

path 15 degrees below the initial path—

or at the steepest nose down attitude 

that the system will permit with full 

control authority if less than 15 degrees. 

Note: The pilot’s controls may be in the 

neutral position after reaching VC/MC and 

before recovery is initiated. 

(c) Recovery may be initiated three 

seconds after operation of high speed 

warning system by application of a load 

of 1.5 g (0.5 acceleration increment) or 

such greater load factor that is 

automatically applied by the system 

with the pilot’s pitch control neutral. 

Power may be reduced simultaneously. 

All other means of decelerating the 

airplane, the use of which is authorized 

up to the highest speed reached in the 

maneuver, may be used. The interval 

between successive pilot actions must 

not be less than one second. 

(d) The applicant must also 

demonstrate that the design dive speed, 

established above, will not be exceeded 

during pilot-induced or gust-induced 

upsets in non-symmetric attitudes. 

(e) The occurrence of any failure 

condition that would reduce the 

capability of the overspeed protection 

system must be improbable (less than 

10¥5 per flight hour). 

Issued in Renton, Washington, on April 4, 

2007. 

Stephen P. Boyd, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service. 

[FR Doc. E7–6889 Filed 4–11–07; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2007–27552; Directorate 

Identifier 2007–NE–11–AD; Amendment 39–

15019; AD 2007–08–02] 

RIN 2120–AA64 

Airworthiness Directives; Hartzell 

Propeller Inc. Model HC–E4A–3( )/ 

E10950( ) Propellers 

AGENCY: Federal Aviation 

Administration (FAA), Department of 

Transportation (DOT). 

ACTION: Final rule; request for 

comments. 

SUMMARY: The FAA is adopting a new 

airworthiness directive (AD) for Hartzell 

Propeller Inc. model HC–E4A–3( )/ 

E10950( ) propellers. This AD requires 

initial and repetitive inspections and 

rework of the propeller blade retention 

radius, and replacement of the propeller 

blade thrust bearing, for each blade. 

This AD results from reports of 

excessive propeller vibration and of 

damaged or broken propeller blade 

thrust bearings found during routine 

and investigative propeller disassembly. 

We are issuing this AD to prevent 

propeller blade separation, damage to 

the airplane, and possible loss of 

airplane control. 

DATES: This AD becomes effective April 

27, 2007. The Director of the Federal 

Register approved the incorporation by 

reference of certain publications listed 

in the regulations as of April 27, 2007. 

We must receive any comments on 

this AD by June 11, 2007. 

ADDRESSES: Use one of the following 

addresses to comment on this AD: 

• DOT Docket Web site: Go to 

http://dms.dot.gov and follow the 

instructions for sending your comments 

electronically. 

• Government-wide rulemaking Web 

site: Go to http://www.regulations.gov 

and follow the instructions for sending 

your comments electronically. 

• Mail: Docket Management Facility; 

U.S. Department of Transportation, 400 

Seventh Street, SW., Nassif Building, 

Room PL–401, Washington, DC 20590–

0001. 

• Fax: (202) 493–2251. 

• Hand Delivery: Room PL–401 on 

the plaza level of the Nassif Building, 

400 Seventh Street, SW., Washington, 

DC, between 9 a.m. and 5 p.m., Monday 

through Friday, except Federal holidays. 

Contact Hartzell Propeller Inc. 

Technical Publications Department, One 

Propeller Place, Piqua, OH 45356; 

telephone (937) 778–4200; fax (937) 

778–4391, for the service information 

identified in this AD. 

FOR FURTHER INFORMATION CONTACT: Tim 

Smyth, Aerospace Engineer, Chicago 

Aircraft Certification Office, FAA, Small 

Airplane Directorate, 2300 East Devon 

Avenue, Des Plaines, IL 60018; e-mail: 

tim.smyth@faa.gov; telephone: (847) 

294–7132; fax: (847) 294–7834. 

SUPPLEMENTARY INFORMATION: We have 

received reports of excessive propeller 

vibration, and of damaged or broken 

propeller blade thrust bearings on 

Hartzell Propeller Inc. model HC–E4A–

3( )/E10950( ) propellers found during 

routine and investigative propeller 

disassembly. At least 15 propellers have 

been reported with broken propeller 

blade thrust bearings. During teardowns, 

instances of bearing failures have been 

progressively more severe, with more 

internal damage to the hub noted. 

Service history shows the propellers can 

safely accumulate 2,000 operating hours 

time-since-overhaul (TSO) before the 

unsafe conditions start to appear. A 

broken thrust bearing can lead to 

damage to the propeller hub and blade 

shank, and blade separation from the 

hub. These damaged or broken parts can 

also lead to damage to the internal 

propeller pitch change mechanism, 

resulting in loss of propeller pitch 

control or in difficulty in feathering the 

propeller. This condition, if not 

corrected, could result in propeller 

blade separation, damage to the 

airplane, and possible loss of airplane 

control. Repairing the propeller blade 

retention radius using the instructions 

cited in Hartzell Propeller Inc. Service 

Bulletin (SB) No. HC–SB–61–287, 

Revision 2, dated October 24, 2006, 

allows the propeller to safely operate for 

3,000 hours before requiring bearing 

replacement. 

Relevant Service Information 

We reviewed and approved the 

technical contents of Hartzell Propeller 

Inc. SB No. HC–SB–61–287, Revision 2, 

dated October 24, 2006. That SB 

describes procedures for initial and 

repetitive propeller blade inspection, 

rework, and thrust bearing replacement, 

for each blade. 


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