February 11th, 2011. 

GCF-0177/2011 – 1/7 

CPA 

Embraer S.A.

Av. Brigadeiro Faria Lima, 2.170 

12227-901 - S.J. dos Campos - SP 

Brasil 

Fone: (12) 3927-0716 

Fax: (12) 3927-1184 

PC: 179
GCF-0177/2011 – 2/7

Summary 

Petitioner: EMBRAER Empresa Brasileira de Aeronáutica S/A 

Section of the Regulation Affected: 14CFR §25.981(a)(3) amendment 102. 

Description of Relief Sought: Embraer petition for a time-limited exemption from 14 CFR 

§25.981(a)(3) for the fuel pump and wiring installation of EMB-135BJ (Legacy 650) 

aircraft. 
GCF-0177/2011 – 3/7

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 

installation 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 

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 fuel system of the EMB135BJ (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 support failures have been identified that could cause non 

intrinsically 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 burn through of the tank. To date sufficient 

information 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. 
GCF-0177/2011 – 4/7

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 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 number 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 concern require significant aircraft 

utilization and/or aging to develop into noncompliant 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 million 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 concern will be mitigated with the actions that are 

described below. 
GCF-0177/2011 – 5/7

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 potting 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 wiring adjacent to all fuel tanks is installed according to the drawings; 

b. 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 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 fuel system limitation task number 

SMRD-1533 tasks 28-17-01-720-001-A01 and 28-50-01-220-001-A01 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 fuel system limitation task number SMRD tasks 28-17-01-720-001-A01 and 

28-50-01-220-001-A01 detailed inspections will 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 performed. These fuel limitation 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. 
GCF-0177/2011 – 6/7

• Fuel System Limitation Task Numbers as follows: 

The DET 20-00-00-220-001-A10 periodic maintenance task requires, at each 18 

months, the wire bundles at areas of concern adjacent to the fuel tank skins to be 

inspected, thus assuring no wiring support failure would persist. 

Issue of Public Interest 

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

of the EMB-135BJ (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 agreedupon 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 
GCF-0177/2011 – 7/7

comparison to this previous exemption, this petition requests only 21 months (measured 

from February, 2011) to complete the identified modifications and retrofitting the 

delivered airplanes. In 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 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 102. There are 689 such aircraft 

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

in 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, 30th 2011, 

with 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.