FEB-17-2011 13:49 Fflfl RENTON P.02/1 1 

Exemption No. 10180 

UNITED STATES OF AMERICA 

PARTMENT OF TRANSPORT AT 

FEDERAL AVIATION ADMINISTRATION 

DEPARTMENT OF TRANSPORTATION _j -^<^~z 

RENTON. WASHINGTON 98057-3356 u 

In the matter of the petition of 

Embraer 

for an exemption from § 25,981(a)(3) of Title 

14, Code of Federal Regulations 

Regulatory Docket No. FAA-2010-1265 

GRANT OF EXEMPTION 

By letters dated December 13,2010 and February 11,2011, Mr. Sergio Augusto Viana de 

Carvalho, Airworthiness Manager, Empresa Brasileira de Aeronautica, S.A. (Embraer), Av. 

Brigadeiro Faria Lima, 2,1709, 12227-901 -S . J. dos Campos-SP, Brazil, petitioned the FAA, 

for an exemption from the teqairemems of § 25.98 J (aX^) of Title } 4, Code of Federal 

Regulations (14 CFR). This exemption, if granted, would permit relief from the fuel tank 

ignition prevention requirements for its EMB-135BJ airplanes modified in accordance with 

Design Change Approval (DCA) 0145-000-00020 (most recent FAA approved revision) (Legacy 

650). 

The petitioner requests relief from the following regulation: 

Section 25.981(a)(3) aa amended by Amendment 25-102: 

(a) No ignition source may be present at each point in the fuel tank or fuel tank system 

where catastrophic failure could occur due to ignition of fuel or vapors. This must be 

shown by; 

(3) Demonstrating that an ignition source could not result from each single failure, from 

each single failure in combination with each latent £ulure condition not shown to be 

extremely remote, and from all combinations of failures not shown to be extremely 

improbable. The effects of manufacturing variability, aging, wear, corrosion, and likely 

damage must be considered. 
FEB-17-2011 13:49 Fftfi RENTON P.03/1 1 

The petitioner supports its request with the foliowing information: 

This section quotes, in part, the relevant infomiation from the petitioner's documentation. The 

complete documentation is available at the Department of Transportation's Federal Docket 

Management System, on the Internet at hltp://rcgulations.gov, in Docket No. FAA-2010-1265. 

Embraer respectfully submits the enclosed petition for a time-limited exemption from the 

provisions of 14 CFR 25.981(a)(3) as they apply to the fuel pump and wiring installations 

of EMB-135BJ (Legacy 650) aircraft. 

Text of the Requirement for which exemption is sought 

14 CFR 25.981(a)(3) "Fuel tank ignition prevention." 

Demonstrating that, an ignition source could not result from each single failure, from 

each single failure in combination with each latent failure condition not shown to be 

extremely remote, and from all combinations of failures not shown to be extremely 

improbable. The effects of manufacturing variability, aging, wear, corrosion, and likely 

damage must be considered. 

Background 

It has proven impractical to demonstrate compliance with § 25.981(a)(3) at amendment 

25-102 in a timely manner due to certain EMB-135/145 family fuel system design 

concepts and practices initially proposed to be retained for the EMB-135BJ (Legacy 

650), Embraer requests that this time limited exemption be granted until practicable 

design solutions are identified, validated, and safely integrated into the fiiel system of the 

EMB-135BJ (Legacy 650). 

Some of design aspects that must be addressed by subsequent modifications include, but 

may not be limited to: 

• Each fuel pump wiring harness within a fuel tank needs an additional independent 

and robust layer of protection against ignition source producing faults. Consideration is 

being given to placing the harness completely within a robust conduit which protects the 

harness from foreseeable damage while protecting the tank vapor space from any 

foreseeable harness faults (i.e. conduit provides vapor/explosion proof barrier that won't 

be lost due to damage from any foreseeable harness fault); 

• Fuel pump explosion proof features need to be made adequately fail-safe. Failures 

that are not extremely improbable have been identified which can cause loss of the pumps 

explosion containment capability. Fixes have been identified and are currently being 

validated; 

• The wiring installations outside the fuel tanks must be made adequately fail-safe. 

Foreseeable wiring suppon failures have been identified that could cause non intrinsically 
FEB-17-2011 13:49 Ffifl RENTON P.04/11 

safe wiring to come into contact with the external skins of fuel tanks. Shorting of the 

conductors within these wires and the conductive skin of the tank could result in 

prohibited hot spots or bum through of the tank To date sufficient infomiation is not 

available to rule out such a short. Some specific fixes have been identified and are 

currently being validated, and the analysis to assure other foreseeable failures do not exist 

is still in process. 

Embraer offers the following justification in support of this exemption, as well as, 

substantiation as to why the current type design provides an adequate level of safety for 

the interim period of this exemption and why granting the time limited exemption is in 

the public interest, as required by 14 CFR 11.81. 

Grounds Supporting Exemption 

Embraer will certify and incorporate into the production line of the EMB-135BJ (Legacy 

650) the modifications required to demonstrate compliance with the requirements of 

§ 25.981(a)(3) at amendment 25-102 by September 30, 2011. 

Embraer will also retrofit the EMB-135BJ (Legacy 650) series airplanes delivered under 

the terms of this exemption by September 30, 2012. 

These proposed dates are adequate considering that: 

• The nimiber of the airplanes that will be delivered within this period represents a 

negligible addition to the overall fleet risk. 

• Some of the identified failure modes of concem require significant aircraft 

utilization and/or aging to develop into noncompllant failure conditions, and the 

timeframe proposed for this exemption is not sufficient for the affected airplanes 

to accumulate the flight hours or cycles required for the components to exhibit 

these aging effects. 

• The fuel pump and wiring installations of the EMB-135BJ (Legacy 650) have the 

same characteristics as the rest of the EMB-145 family from which it is derived. 

That EMB-145 family has accumulated more than 17 mi 11 ion flight hours without 

notable adverse experience relevant to the objectives of the § 25.981(a)(3) 

requirement. 

• There are five EMB-135BJ (Legacy 650) aircraft scheduled to be delivered to 

U.S. customers through the end of 2011. The additional number of flight hours 

that will be accumulated by these EMB-135BJ (Legacy 650) airplanes during the 

period of this exemption will be minimal due to that limited fleet size and the 

lower annual utilization typical of such business jets. 

• The failure conditions of concem will be mitigated with the actions that are 

described below: 
FEB-17-2011 13:49 FAA RENTON P.05/11 

The proposed mitigation actions for pump manufacturing and assembly within this timelimited exemption application are the following: 

1. Additional dielectric strength test on the pump harness before final assembly to 

guarantee the proper wiring insulation. 

2. Torque verification of pump locking nuts at final inspection to guarantee the 

proper installation of the nut. 

3. Addition of polysulfide sealant all over the pump locking nuts to guarantee the 

closure of the gap between stud and cover and, consequently, the explosion proof 

cavity. 

4. Additional cleaning task to guarantee the adhesion of pottmg to connector counter 

bore. 

5. In addition to the already existing inspections, a detailed visual inspection 

performed by qualified quality inspector to guarantee that 

a. The wuing adjacent to all fuel tanks is installed in accordance with drawings; 

b. The pump harness is installed according to the drawing to include 

i. Clamp type (with yellow cushion) 

ii. Clamp size 

ill. Clamp alignment with the harness 

iv. Correct number and location of clamps 

v. Harness slack properly distributed along the length 

vi. Harness clearance 

The proposed limitation for pump maintenance within this time-limited exemption 

application is the following: 

Any maintenance action accessing the wing tanks collector box or any auxiliary fuel 

tanks to perform any maintenance either on the fuel pump itself or other adjacent 

component or installation requires a detailed visual inspection and a functional check 

in accordance with the fiael system limitation task numbers 28-17-01-720-001-AOl 

and 28-50-01-220-001-AOI by a qualified inspector in order to guarantee that the 

installation of the pumps are in accordance with the Maintenance Manual instructions 

and illustrations. 

The fiiel system limitation task numbers 28-17-01-720-OOl-AOl and 28-50-01-220-

001 -AOl vwll include a GVI (General Visual Inspection) task number 28-41-00-200-

801-A as part of the tank closure procedure after a maintenance activity is perforated. 

These fuel limitation tasks will be added to the Embraer maintenance plaiming guide 

(MPG) temporary revision (TR) 7.2, before certificate of airworthiness or first 

delivery whichever occurs later. 
FEB-17-2011 13:50 FAA RENTON P.06/11 

Fuel System Limitation Task Numbers as follows: 

2B-17-01-720^001'A01 

2e-scM)i-22(wni-flm 

FNC 

OCT 

Functionally CtMck Venir»l Unx oUical bondlrtg hiegmy ol Fuel 

Pump. TQOa conneciorr at tank wall Dy oonducUvfty 

meouremertts 

NOTE: AfipicacietDaiFrnfiEqulPPMwitnvenftt Fuel Tank 

•ndAE3D0rA2 Engines 

InSMCi (DeU M Invecton) Ftwl PUTV ElKtriori HHTKH 

NOTE: ApcCctfdvtodnnftEqtippadWftVenMRfllTanh 

dndJeaOOTiCEnaim 

193/1934/ 

1972 

i»i5 e 

192 

aaaooFH 

crl^M O 

10.000 FH 

0-48 w o 

ALL 

ALL 

The DET 20-00-00-220-OOl-AlO periodic maintenance task requires a periodic 

repetitive inspection of wire bundles to areas of concem adjacent to the fuel tank skins, at 

an interval of 18 months, to assure no wiring support failure persists. 

204)0^-220-

QOl-AIQ 

Dm" rnspea (PoTiilcd Inspection) all EWIS componenu of 

Ihc iin:nifl. 

NOTE: EWIS. 

NOTE: Applicable to nircraA equipped with ventral 

niel ank and AE3007A2 engines under FAA 

certiflcuion. 

18 mo ALL 

Issue of Public Interest 

Denial of this petition for exemption would result in the delay in certification and 

delivery of the EMB-I35BJ (Legacy 650) to the United States (U.S.). While these 

airplanes are not manufactured in the U. S., a significant portion of the airplane. Including 

the engines, avionics, and interiors are manufactured by U.S. suppliers. Denial of this 

exemption request would result in the loss of revenue for the U.S. suppliers and have an 

adverse impact on the U.S. balance of trade, both of which are counter to the public 

interest. 

In addition, our U.S. customers have made fleet schedule plans based on the agreed-upon 

delivery schedule of these airplanes. To require Embraer to modify these airplanes prior 

to service entry will unavoidably delay delivery and have an adverse financial effect on 

these operators. This action would be counter to the public interest. 

Request to Forego Publication in the Federal Register 

Because this exemption petition is similar in both the technical and regulatory aspects 

addressed and the temporary relief sought to an exemption that has been issued in the 

past (Exemption 8761C) and has received no public comments, granting of this proposed 

exemption would not raise new issues or set any legal precedent. In comparison to this 

previous exemption, this petition requests only 21 months (measured from January I, 

2011) to complete the identified modifications and retrofitting the delivered airplanes. In 
FEB-17^2011 13=50 FAA RENTON P.07/11 

addition, the previous exemption was applicable to the entire fuel system, where in the 

case of the EMB-135BJ (Legacy 650), the majority of the affected system has already 

been shown compliant with 14 CFR 25.981(a)(3) and the necessary modifications 

identified. Accordingly Embraer requests that the FAA not delay granting of this 

exemption for publication of the petition summary in the Federal Register as allowed by 

14 CFR 11.87. 

Embraer has a contract with an U.S. operator to deliver the first EMB-135BJ (Legacy 

650) by February 25,2011, As described above in the Public Interest section, a delay in 

delivery will adversely affect this operator, forcing him to seek alternatives to his planned 

use of the airplane, e.g., cancel scheduled flights, charter alternative lift. 

Embraer also notes that this petition was filed immediately after the identification of the 

non-compliance. 

In summary, there exists the necessary justification for forgoing publication of a petition 

summary in the Federal Register, and Embraer respectfully requests that [the FAA] grant 

this petition without delay. 

Effect of the Exemption on Safety 

The entire EMB-145 family of aircraft have similar design features that could not be 

shown to comply with § 25.981(a)(3) amendment 25-102. There are 689 such aircraft 

currently operating safely within the U.S. fleet. Such aircraft have been operating safely 

hi the U.S. for over 14 years and are expected to continue to do so for many years to 

come. Adding 5 additional aircraft expected to be delivered until September 30**^ 2011, 

wdth a similar level of risk to that fleet for less than two years will clearly have a 

negligible impact on safety. 

Operations Outside the United States 

As a manufacturer and not an operator, Embraer does not intend to operate outside the 

United States under the terms of the exemption which we are requesting, but our 

operators will certainly fly the EMB-135BJ (Legacy 650) internationally. The granting of 

this petition will not conflict with any of the terms of ICAO Annex 8, so the FAA will 

not need to file a difference with ICAO, as described in 51 1.83. 

Federal Register Publication 

The FAA has determined that good cause exists for waiving the requirement for Federal Register 

publication because the exemption, if granted, would not set a precedent, and any delay in acting 

on this petition would be detrimental to Embraer. 
FEB-17-2011 13:50 Fflfl RENTON P.08/1 1 

The FAA's analysis 

FAA Analysis - Introduction 

To obtain this exemption, the petitioner must show, as required by § 11.81 (d), that granting the 

request is in the public interest, and. as required by § 11.81(e), that the exemption will not 

adversely affect safety, or that a level of safety will be provided that is equal to that provided by 

the rules from which the exemption is sought. 

FAA Analvsis - Public Interest 

The FAA agrees with the petitioner that the adverse impacts on U.S. interests, including 

component manufacturers and operators of delaying approval of this type design amendment for 

approximately one year is not warranted as this granting would not materially impact the level of 

safety given the limited exposure being allowed, and the unusually vigilant maintenance being 

required by the conditions of this exemption. 

FAA Analysis • Effect on Safety 

The petitioner estimates that at most 5 airplanes of the noncompliant type design airplanes will 

be delivered to U.S. operators, and these will be operated for at most two years before being 

brought into comphance with the subject rule. Based on the good service history demonstrated 

by the existing fleet with similar designs, and the limited time in which the new airplanes will be 

operating, the risk to safety within the U.S. fleet of granting this exemption is very low. 

Embraer's proposal for additional assembly steps and maintenance actions v^ll further mitigate 

the risk. The FAA plans to evaluate the risk within the existing Embraer fleet to determine 

whether the design changes that Embraer will develop should be incorporated into these other 

airplanes. 

The FAA's Decision 

In consideration of the foregoing, I find that a grant of exemption is in the public interest. 

Therefore, pursuant to the authority contained in 49 U.S.C. §§ 40113 and 44701, delegated to me 

by the Administrator, Embraer is hereby granted an exemption fiom the requirements of 14 CFR 

25.981(a)(3) as they relate to the Model EMB-I35BJ (Legacy 650) airplane, fuel pump and 

wiring installations, with the following conditions and limitations: 

1. For Model EMB-135BJ (Legacy 650) airplanes granted a certificate of airworthiness 

before September 20,2011. The following compensating features identified by the petitioner in 

their petition shall be mandatory: 

a. Additional dielectric strength test on the pump harness before final assembly to 

assure the proper wiring insulation. 
FEB-17-2011 13:51 FAA RENTON P.09/11 

b. Torque verification of pump locking nuts at final inspection to assure the proper 

installation of the nut. 

c. Addition of polysulfide sealant all over the pump locking nuts to assure the 

closure of the gap between stud and cover and, consequently, the explosion proof 

cavity. 

d. Additional cleaning task to assure the adhesion of potting to connector counter 

bore. 

e. In addition to the already existing inspections, a detailed visual inspection 

performed by a qualified inspector to assure that: 

(1) the wiring adjacent to all fuel tanks is installed according to the 

drawings; and 

(2) the pump harness is installed according to the drawing to include: 

i. Clamp type (with yellow cushion). 

ii. Clamp size. 

iii. Clamp alignment with the harness, 

iv. Correct number and location of clamps, 

V, Harness slack property distributed along the length, and 

vi. Harness clearance. 

f The proposed limitation for pump maintenance within this time-limited 

exemption application is the following: 

(1) Any maintenance action for accessing the wing tanks collector box or 

any auxiliary fuel tanks for performing any maintenance, either on the 

fuel pump itself or other adjacent components or installations, requires 

a detailed visual inspection and a functional check in accordance with 

the fijel system limitation task numbers 28-17-01-72a-OOI-A01 and 

28-50-01-220-001-AOl, by a qualified inspector, in order to assure that 

the installation of the pumps are in accordance with the maintenance 

manual instructions and illustrations. 

(2) The fuel system limitation task numbers 28-17-01-720-001-AOl and 

28-50-01-220-001-AOl will include a GVI (General Visual Inspection) 
FEB-17-2011 13:51 FAA RENTON P.10/11 

task number 28-41-00-200-801-A, as part of the tank closure procedure 

after a maintenance activity is performed. These fuel iimitation tasks 

will be added to the Embraer maintenance planning guide (MPG) 

temporary revision (TR) 7.2, before certificate of airworthiness or first 

delivery whichever occurs later. 

Fuel System Limitation Task Numbers as follows: 

28-17-01-720-001'AD 1 

2S^CM)1.22M30-V-A01 

FNC 

DET 

Functionally Check ventral KnK cnucai tModlnp Megniy or Pud 

Punp. FOGS conncaor» i t m k wai by conouotvitf 

mejuurcments 

N0T6: AppncacKe to alTtTanE<)uippMwinvefWBi Fuel Tank 

«nd AE30Q7A2 Engnei 

InapMt (DiM M liapeciDn) Fun PiAlp E)K&icri Himeai 

NOmE: AKietU * to *craiE«ippedidtiViBnM Fuel Tank 

a«fAE300rA2Bi^nM 

193/1924/ 

1972 

isfin$6 

192 

30.000 FH 

or 144 MO 

V4SM 0 

ALL 

ALL 

g. The DET 20-00-00-220-001-AlO periodic maintenance task requires a periodic 

repetitive inspection of the wire bundles to areas of concem adjacent to the fuel tank 

skins, at an interval of 18 months, to assure no wiring support failure persists. 

20-00-00-220-

001-AlO 

DET Inspect (Detailed Inspection) all EWIS componenu of 

the Aircraft. 

NOTE: EWIS. 

NOTE: Applicable to aircnifl equipped with vcnnl 

fuel tank and AE3007A2 cngineE under FAA 

certification, 

18 mo. ALL 

2. The "Airworthiness Limitation" section of the "Instructions for Continued 

Airworthiness" will state that these airplanes cannot be operated after September 30,2012, 

unless the design changes submitted in accordance with limitation 3 (below) are incorporated by 

the owner or operator. 

3. On or before September 30,2011, Embraer shall obtain FAA type certification 

approval of an amendment to the EMB-135BJ (Legacy 650) type design which fully complies 

with the provisions of § 25.981(a)(3) at Amendment 25-102 or later 

4. On or before March 30,2012, Embraer will develop and submit for FAA approval, 

service information to incorporate any design changes and/or operating and maintenance 

limitations developed to meet the provision of § 25,981 (a)(3), as identified in limitation 2 

(above). 
FEB-17-2011 13=52 FOfi RENTON P.11/11 

5. Airplanes for which application for airworthiness certificate is made after September 

30,201U must incorporate any design changes and/or operating and maintenance limitations 

developed to meet the provisions of § 25.981(a)(3), as identified in limitation 2 (above). 

6. The FAA will not issue original airworthiness approvals for Model EMB-13SBJ 

(Legacy 650) airplanes after September 30,2012, unless Embraer has shown full compliance 

with the provisions of this exemption by that date. 

Issued in Renton, Washington, on rr n f c 2011 

Ali Bahrami 

Manager, Transport Airplane Directorate 

Aircraft Certification Service 

10 

TOTAL P.11