1 of 4

Gulfstream Aerospace LP ¤ PO Box 1036 ¤ Airport City 70100 ¤ ISRAEL

Tel: +972-3-935-6624 ¤ Fax: +972-3-935-6750 

### December 18, 2013 GALP Ref: FAA/13195/CG

Mr. Thomas Stafford Program Manager, International Branch, ANM-116
Federal Aviation Administration Transport Airplane Directorate
Aircraft Certification



### Subject: Time Limited G280 FAA Exemption No. 10613 – Request for extension.

Dear Mr. Stafford,

On August 28, 2012 the Federal Aviation Administra tion granted exemption 10613 (petition and grant attached) for relief from the following parts of 14 CFR:

14 CFR §25.901(b)(1)(i) & (b)(2), §25.903(d)(2), 25.939(a), 25.1301(a),(c) & (d), 25.1309(c), 25.1322 and 25.1549(a)

Gulfstream Aerospace LP (GALP) originally requested four years in which to accomplish the development of an effective solution. FAA limited the exemption to two years as-granted.



### As-granted, the exemption covers a condition on th e G280 airplane whereby an extremely remote risk of an Inter-Turbine Temperature (ITT) exceedance warning message might occur under certain
conditions.

Conditions for this to occur were specified by FAA in original Grant of Exemption:

- Field elevation greater than 8,000 feet

- Icing conditions present (less than 10 degrees C / visible moisture)

- Pilot would have to fail to recognize icing potential and not activate the system prior to take-off or initiation of approach procedures

- Co-pilot would have to overlook the pilot’s fa ilure to activate the Wing Anti-Ice System despite defined procedures

- Crew then recognizes the error and activates the WAI System while at take-off or goaround power

Type Certification including Flight Into Known Icing was granted under the caveat of this exemption.

GALP has been working diligently with IAI Engineering and Honeywell to meet the 2 year window that was originally granted, including the various target dates as outlined in the granted exemption. Every effort has been expended to develop system improvements that would optimize the aircraft and engine control system and indication software so as to preclude the possibility of an ITT2 of 4

Gulfstream Aerospace LP ¤ PO Box 1036 ¤ Airport City 70100 ¤ ISRAEL

Tel: +972-3-935-6624 ¤ Fax: +972-3-935-6750 

### exceedance indication during certain high-bleed demand conditions within the requirements outlined by the exemption.

GALP hereby requests additional time to effect a full remedy as technical development has proved as time-consuming as first envisioned by the original petition. GALP also holds that the original standing for no need of publication for comment remains valid as the original technical premise for the exemption remains not only valid, but is improved by progress to-date as outline herein. Further, the same business case exists and a delay would be costly in terms of public interest and to commerce. Substantial progress toward the demonstration of compliance to the affected regulations has been made and a path to a full solution is now before us. However, completion of development and implementation of a means to show full compliance will require an additional effort and time.

Therefore GALP hereby requests additional time to be granted so as to effect a full remedy and by this request submits a basis for confidence:

Substantial improvements have been developed and implemented in Honeywell FADEC Software V 1.5. Additionally, further system improvements are currently in flight testing that will fully address the condition for all reasonable scenarios and permit full compliance:

Two essential changes are planned: - FADEC Software Version V 1.5 implementation (TC MOD G25-20061) - GADC Software upgrade and introduction of a Crossover Duct Valve (TC MOD G25-10022)

to remove ‘flow-hogging’ during dual-source (normal) demand conditions

Milestones for the various design changes intended to provide interim mitigation and finally to reach full compliance and resolve the exemption issues, i.e. design approval milestones are as follows:

- FADEC Software V1.5 –

o FAA approved Honeywell Service Bulletin AS907-76-9016 is now released (FAR 33 change); and a corresponding Gulfstream Service Bulletin is planned for release in January 2014. GALP intends to complete full fleet implementation no later than 30 September, 2014.. Production incorporation began with serial number 2034 (November 11, 2013)

o Improvements:

 FADEC V1.5 increases ITT limits from 946C to 955C to provide better airframe match / decrease ITT exceedance possibilities; also fine-tuned
debit structure for dual-source in-air activation to alleviate ITT exceedance potential in certain conditions

 Accordingly GALP notes an early and positive improvement to the reduction of exposure to possible ITT exceedance that is substantially in keeping both with the intent and timeline of the current exemption
deadlines

- GADC Software upgrade coupled with installation of a new Wing Anti-Ice Crossover Duct Valve to eliminate flow-hogging during dual source (normal) operations –

o This design is being updated and tested for full optimization and is proving to be a solid way forward to solve the issues that remain after the FADEC V1.5 update

o GADC Software Improvements:

 Will control the Crossover Valve optimizing Wing Anti-Ice valve functionality, and minimizing WAI flow induced exceedance possibilities. . Certification and production cut in scheduled for April 20143 of 4

Gulfstream Aerospace LP ¤ PO Box 1036 ¤ Airport City 70100 ¤ ISRAEL

Tel: +972-3-935-6624 ¤ Fax: +972-3-935-6750 

### By this it can be seen that in spite of the significant efforts by all parties the current deadlines imposed by the existing exemption cannot be met. However, it is important to highlight that the public interest and safety aspects associated with this exemption are improved in comparison to those at the time of the granting of the exemptio n by virtue of the on going implementation of FADEC software V1.5 in production and in service which su bstantially reduces fleet exposure to the original event risk. Subsequent full compliance with the requirements set forth by the exemption is envisioned as the GADC Software upgrade and introduction of a Crossover Duct Valve is implemented following certification of this TC MOD.

GALP therefore respectfully requests an extension per the above improvements to-date and as now forecast in lieu of the original dates require d by the exemption as-granted in the “The FAA’s Decision” section of the exemption:

- Item 1 – Validation and substantiation of operational conditions as specified by FAA – already satisfied prior to Type Certification and remaining compliant as-such

- Item 2 – Airworthiness Limitation requirement imposed on the Instructions for Continued Airworthiness (ALS of the AMM)

o Per this requirement the ALS section of the AMM contains the stipulated operational restricted deadline of September 30, 2014

o GALP respectfully requests consideration of an extension to December 31, 2015

 This time is needed to support the remaining developmental and/or implementation needs relevant to all required features – initially FADEC V1.5, and finally the WAI Crossover Duct / Valve and GADC upgrade

- Item 3 – FAA type-certification approval of amended type design to eliminate noncompliant features

o Exemption now requires FAA approval of the complete design change needed for full compliance by January 10, 2014

 Design change data for FADEC V1.5 is now available (approved by the FAA under FAR 33 design change)

 Design change data for the GADC Software upgrade and Crossover Duct Valve changes (TC MOD G25-10022) will be available in April of 2014

o GALP submits that the initial design change – FADEC V1.5, represents a substantial improvement for which FAA approval has already been obtained and therefore significantly supportive of the existing requirement for the January 10, 2014 requirement for review of data

o The design data for the remaining / forecast changes – GADC upgrade and the WAI Crossover Duct Valve installation (TC MOD G25-10022) should be available for FAA consideration and approval in April of 2014

o Accordingly, GALP requests that the date by which FAA approval of the design changes required to eliminate any non-compliant design features be revised to 30 June, 2014.

- Item 4 – Develop, validate and submit for FAA approval all service information necessary to incorporate the design changes required in Item 3 above:

o FADEC V1.5 –the Gulfstream Service Bulletin to implement this change will be submitted to FAA for approval by 31 January, 2014

.

o GADC upgrade and the WAI Crossover Duct Valve installation - – the Service Bulletin to implement this change will be provided to the FAA for approval by May
of 2014

o Accordingly, GALP requests that the date by which FAA approval of all service information necessary to incorporate the design changes required be revised to 30 June, 2014.4 of 4

Gulfstream Aerospace LP ¤ PO Box 1036 ¤ Airport City 70100 ¤ ISRAEL

Tel: +972-3-935-6624 ¤ Fax: +972-3-935-6750 

### - Item 5 – Airplanes for which application for airworthiness approvals is made after September 30, 2014

o Requires relief due to time require d to get existing (in-service) fleet fully modified – December 31, 2015 is requested

- Item 6 – FAA will not issue original airw orthiness approvals for GALP Model G280 Airplanes after September 30, 2014

o No extension appears needed for this date due to planned certification and production cut-in of all modifications outlined herein which are expected to be approved before this date

As presented herein, our request for extending the deadlines associated with the design change and service information approvals is relatively modest compared to extension request for retrofit of the G280 fleet which presents significant logistics and scheduling challenges associated with the hardware and aircraft availability. GALP remain s aggressive in pursuing and implementing these improvements, and believes the stepped-process of implementing first the FADEC V1.5 change while the GADC upgrade and WAI Crossover Duct Valve design change is being completed provides significant mitigation by improving the level of safety relative to the levels at the time of the original granting of the exemption.

GALP also respectfully requests FAA considerat ion of no need of publication for comment as the technical basis and business need / public interest remains the same as during the original application with regard to FAR 11.87 requirements. Given progress to-date and the improvements that will be implemented during the remaining requested period the conditions addressed by the exemption are actually of diminishing concern, so GALP believes a no publication approach remains fully valid.

GALP is confident that this approach will yield a fully compliant product by the dates provided herein and will appreciate FAA’s earliest consideration of this request, including no delay for publication.



### Regards,

Charly Gaber
GALP Airworthiness & Certification Gulfstream Aerospace LP e-mail: Charly.Gaber@gulfstream.com Telephone: +972-3-935-6627
Fax: +972-3-935-6750

cc: J. Gibbs, B. Marom, S. Bendor, D. Lawton, D.Such,J.Gibbs,J.Neville,T.Nir,I.Kalal M. Fagan, FileGulfstre am Aerosp ace LP ¤ PO Box 1036 ¤ Airport Cit y 70 100 ¤ ISRAEL

Tel: +972-3- 935-6624 ¤ Fax: +972-3-935-675 0 

### 1 GALP Ref: FAA/12107/CG



## Petition for a Time-Limited Exemption

Gulfstream Aerospace LP (GALP) originally petitioned FAA for a time-limited Exemption from 14 CFR Parts 25.901(b) (2) and 25.903(d) (2) on May 17, 2012, as recorded in docket FAA-2012-0553.

GALP hereby amends that original petition by request ing a time-limited exemption from the originally requested rules and from certain additional rules as will follow.

This amended petition is intended to replace the above referenced original petition. GALP respectfully reque st that the original petition dated May 17, 2012 be re moved from this docket and replaced with this submittal accordingly.

- 14 CFR §25.901(b)(2) as amended by Amendment 25-4 6

- 14 CFR §25.903(d)(2) as amended by Amendment 25-1 00

- 14 CFR §25.939(a) as amended by Amendment 25-40

- 14 CFR §25.1301(c) and (d) effective February 1, 1 965

- 14 CFR §25.1305(c)(1) as amended by Amendment 25-1 15

- 14 CFR §25.1322(a) as amended by Amendment 25-38

- 14 CFR §25.1309(c) and (d) as amended by Amendment 25-41

This exemption would permit relief from certain engine installation, operational limitation and engine in dication requirements which apply to the Gulfstream G280 airp lane and installed Honeywell AS907-2-1G engines.

GALP also requests FAA’s early consideration of a gran t of exemption without a public comment period as a delay would be detrimental to Certification of the Gulfstream G280 airplane and to GALP economically.

Regulations from which relief is sought (at amendme nts as referenced above):

Sec. 25.901

Installation.

... (b) For each powerplant-- ... (2) The components of the installation must be constructe d, arranged, and installed so as to ensure their continued safe operation between normal inspections or overhauls;

Sec. 25.903

Engines.

... (d) Turbine engine installations. For turbine engin e installations-- ...Gulfstre am Aerosp ace LP ¤ PO Box 1036 ¤ Airport Cit y 70 100 ¤ ISRAEL

Tel: +972-3- 935-6624 ¤ Fax: +972-3-935-675 0 

### 2 (2) The powerplant systems associated with engine cont rol devices, systems, and instrumentation, must be designed to give reasonable assurance that those engine operating limitations that adversely affect turbine rotor structural integrity will not be exceeded in servic e.

Sec. 25.939

Turbine engine operating characteristics. (a) Turbine engine operating characteristics must be in vestigated in flight to determine that no adverse characteristics (such as stall, surge, or flameout) are p resent, to a hazardous degree, during normal and emergency operation within the range of operation li mitations of the airplane and of the engine.

Sec. 25.1301

Function and installation.

Each item of installed equipment must--

... (c) Be installed according to limitations specified fo r that equipment; and (d) Function properly when installed.

Sec. 25.1305

Powerplant instruments. [ The following are required powerplant instruments: ]... (c) For turbine engine-powered airplanes. In additio n to the powerplant instruments required by paragrap h (a) of this section, the following powerplant instruments are required: (1) A gas temperature indicator for each engine.

Sec. 25.1309

[ Equipment, systems, and installations. ]

... (c) Warning information must be provided to alert t he crew to unsafe system operating conditions, and to enable them to take appropriate corrective action. Syst ems, controls, and associated monitoring and warning means must be designed to minimize crew errors which co uld create additional hazards. (d) Compliance with the requirements of paragraph (b ) of this section must be shown by analysis, and where necessary, by appropriate ground, flight, or simulator tests. The analysis must consider-- ] (1) Possible modes of failure, including malfunctions a nd damage from external sources. (2) The probability of multiple failures and undetect ed failures. (3) The resulting effects on the airplane and occupan ts, considering the stage of flight and operating cond itions,
and (4) The crew warning cues, corrective action required, a nd the capability of detecting faults.

Sec. 25.1322

[ Warning, caution, and advisory lights. ]

[ If warning, caution, or advisory lights are installed i n the cockpit, they must, unless otherwise approved by th e Administrator, be-- (a) Red, for warning lights (lights indicating a haz ard which may require immediate corrective action);

Background, Reasons for Exemption and Supportive In formation:

This exemption, if granted, would permit relief from certain engine installation, limitation, operational and indication requirements for the Gulfstream G280 wher e there is extremely remote possibility that an Inter Turbine Temperature (ITT) exceedance indication during certain Wing Anti-Ice System (WAI System) operations may occur. This exemption would be time-l imited to two (2) years to allow improvements present ly in development to be completed and implemented into t he G280 fleet. Improvements now in-work include optimized aircraft and engine control system and indica tion software designed to preclude the possibility of an engine ITT exceedance indication during certain high-b leed demand operating conditions.Gulfstre am Aerosp ace LP ¤ PO Box 1036 ¤ Airport Cit y 70 100 ¤ ISRAEL

Tel: +972-3- 935-6624 ¤ Fax: +972-3-935-675 0 

### 3 The Gulfstream G280 is nearing the conclusion of a Typ e Certification effort begun by initial application on March 30, 2006 and as extended by FAA agreement thr ough September 30, 2012. Provisional Type Certificate number A61NM was granted on March 1, 2012

.

An operational review of the Wing Anti-Ice System (WA I System) during recent FAA FSB flight and training activities has indicated possible compliance issues wi th the above cited rules. There is an extremely remot e risk that an ITT exceedance warning message might occu r during the initial wing warm-up phase of WAI System operation under certain conditions. Engine bl eed demands during this phase and the current FADEC ITT limits may lead to an indication of engine ITT e xceedance to the flight crew. However, the engine is actually certified to a higher value (955°C continuou s, 970°C maximum for 20 seconds) than the flight deck exceedance indication as-generated by the current FADEC version (928°C). The engine may therefore continue to safely operate without any adverse affect t o the engine or continued safe flight of the aircraft

.

This condition may exist at high power settings, follow ing WAI System activation and until the wing approac hes WAI System steady-state temperatures and engine bleed flow stabilizes, after which engine ITT is reduced. During this warm-up phase it is possible that an ITT e xceedance warning indication may occur. However, should such an indication occur, it is unlikely that the engine is actually experiencing an exceedance condition because the ITT limits as currently set in the FADEC, as stated above, are below the certified engine values b y as much as 27°C. The planned changes include improved a irframe / engine integration functionality by optimizing the bleed-demand / engine response and indi cation functions during WAI System activation, warmup and operation.

As a precautionary measure, GALP has also assessed the possib ility of an actual operational ITT exceedance event during foreseeable flight conditions. As stated above, such an actual ITT exceedance occurring during foreseeable fleet operations is also not likely. The risk of an actual exceedance occurring during an indic ation error event is therefore mitigated as well.

For such an actual exceedance all of the following co nditions, events and related crew actions would have to

occur:

• Field elevation greater than 8,000 feet

• Icing conditions would have to be present (less than 10°C / visible moisture)

• Pilot would have to fail to recognize potential for icing conditions and not activate the system prior t o take-off or initiation of approach procedures

• Co-pilot would have to overlook the pilot’s failure to activate WAI System despite defined procedures

• Crew then recognizes the error and activates the WAI S ystem while at take-off or go-around power

Engines will have ample ITT margins for the two year exemption as-shipped and as monitored and maintained. Appropriate ITT margins provide assurance against reachi ng exceedance values during operation.

GALP respectfully submits this petition for a time-limi ted exemption from the provisions of the above-listed rules until such time as the current design effort can be finalized and changes may be made to the WAI System and engine control systems to optimize the integratio n design and further preclude the risk of an occurren ce of the described exceedance warning indication. GALP anti cipates that these changes will be available by the end of 2013, and will make every effort to ensure th at a fleet retrofit will be completed by the end of the third quarter of 2014. GALP will provide FAA with details for the intended design changes and modifications to achieve full compliance.

Fleet operational experience demonstrates that the hi gh-usage rate for a Gulfstream Mid-Cabin airplane is about 600 hours per year, and that a more typical us age rate is approximately 400 hours per year. Given the limited time-frame for the requested exemption and considering the operational window for the airplane s that would be delivered within a 2 year time-frame, the risk of an ITT exceedance is reduced due to the engines only having a partially deteriorated condition and th ereby would have more margin to an ITT limit than a fully deteriorated engine as used in the margin analysis. T he limited number of airplanes that will be delivere d within the two-year period of the requested exempti on represents a negligible addition to overall flee t risk.

Reasons for Petition for Exemption:Gulfstre am Aerosp ace LP ¤ PO Box 1036 ¤ Airport Cit y 70 100 ¤ ISRAEL

Tel: +972-3- 935-6624 ¤ Fax: +972-3-935-675 0 

### 4 Due to the current configuration of engine FADEC and WAI System control software as reviewed with FAA and intended for Type Certification, it has proven impra ctical to demonstrate full compliance through aircra ft or other system limitations or by system level changes w ith the above-listed rules in a timely manner. GALP therefore respectfully requests that this time-limited exemption be granted without delay to support the timely issuance of a Type Certificate for the Gulfstream G280. This would permit the reasonable development of mitigating improvements in WAI System control and eng ine FADEC software within a workable time-frame.

Type Certification of the Gulfstream G280 to include Flight Into Known Icing (FIKI) is vital to the produ ct. Restricting the operational envelope in this manner, or in any form that otherwise restricts airplane performance is commercially unviable for GALP and its c ustomers and would be very detrimental to the marketability of this aircraft.

Information Supporting Exemption:

GALP offers the following justification and substantiat ion for granting this time limited exemption and as to how the current type design provides an acceptable level o f safety. It should be pointed out that the potenti al for an ITT exceedance warning indication only exists as an extre mely remote possibility.

GALP, with assistance from the engine manufacturer, ha s established that tolerance against the risk of the described exceedance occurring is related to engine ‘m argin’, e.g. a newly-delivered engine has greater ITT temperature margins than an ‘end of life’ engine. A irplanes delivered within the requested 2 year window will have new engines and should accumulate no more than approximately one-eighth of their useful margin-life during that time-span at the average-to-highest airpl ane usage rates. This mitigates any exposure to the condition, should AFM procedures not be followed, as the se margins help offset the likelihood of a high-bleed rate condition driving such an occurrence.

Current aircraft ITT engine limits are below the certi fied engine ITT limits by as much as 27 degrees. Even if a momentary engine ITT exceedance is seen during the b rief period of time while the wing anti ice system heats up the wing, the engine is certified to a highe r value than the airframe exceedance indication as stat ed above (955°C continuous / 970°C maximum for 20 second s vs. 928°C in the current FADEC SW), and will continue to safely operate without any affect to the engine or continued safe flight of the aircraft. The crew can respond to the message, should it occur, with imm ediate action, as required. Such action would be consistent with a message of this type being generated b y any other cause and is therefore functionally withi n the reasonable scope of operation.

GALP’s assessment of the possibility of an actual ope rational ITT exceedance event during foreseeable fli ght
conditions has also shown the likelihood of such an act ual ITT exceedance occurring during foreseeable fleet operations to be extremely remote. Therefore the risk of an actual exceedance occurring during an indicatio n error event is mitigated.

The limited number of airplanes that will be delive red within the two-year period of the requested exem ption represents a negligible addition to overall fleet ri sk.

Normal operational procedures provide ample means by which the crew may avoid the operational issue of an
ITT exceedance indication. The condition of this ex emption will be also be appropriately stressed during pilot type rating and training activities in the Gulfstream G 280 so as to ensure crew awareness of the extremely remote potential for an exceedance warning.

GALP will design, certify and incorporate into Gulfstr eam G280 production line and existing fleet, a series o f modifications required to demonstrate compliance with the requirements of the above listed rules within th e time permitted by this exemption, if granted.

Acceptable Level of Safety is provided –

The overall potential of an ITT exceedance indication is very limited given the number of foreseeable conditio ns that must be present. Analysis of foreseeable fleet operations, the attending risks of an occurrence / icin g event and related operational actions, Airplane Flig ht Manual (AFM) procedures (including prohibition ag ainst operation in WAI System auto-mode) and reliability o f the associated components and systems have shown that an acceptable level of safety is assured.Gulfstre am Aerosp ace LP ¤ PO Box 1036 ¤ Airport Cit y 70 100 ¤ ISRAEL

Tel: +972-3- 935-6624 ¤ Fax: +972-3-935-675 0 

### 5 In addition to appropriate procedures, clear placarded information will be present in the cockpit to prohibit operation of the WAI System in auto-mode. When the WAI System is switched off, system probability fail ures that could cause Uncommanded activation of WAI are ext remely improbable and are not caused by a single
failure.

To further mitigate any risk of an event that might occur from unforeseen rapid engine deterioration in -service, it is also proposed that an interim power assurance ch eck be performed at “A check” at 500 hours, or “C che ck” at 12 months, whichever comes first. This is to ensure that appropriate ITT margins are maintained in-servi ce.

The MMEL will prohibit single bleed source dispatch o r other dispatch configuration limitations which are fundamental to the exemption being requested.

Public Interest / Benefit:

GALP offers the following reasons for why granting th e requested time-limited exemption is in the public interest, as required by 14 CFR 11.81:

Denial of this petition for exemption would result i n the delay in Type Certification and delivery of th e Gulfstream G280. While these airplanes are not manufa ctured in the U.S., a significant portion of the ai rplane, including the wings, engines, avionics, and interior s are manufactured by U.S. suppliers. Denial of this exemption would result in the loss of revenue for th e U.S. suppliers and have an adverse impact on the U. S. balance of trade, both of which are contrary to the p ublic interest.

Granting this exemption would permit the efficient t ransport of employees, corporate executives and importa nt clientele in an efficient and safe environment. Due to the high demand for these corporate aircraft, it i s imperative that the petitioner is granted the regulat ory relief requested. Failure to achieve this goal w ill result in delivery delays and the potential for significant loss o f income, in both domestic and foreign trade for the United States and the petitioner. Therefore the stabilizing effect that the manufacture and support of corporate aircraft has on the job market and balance of trade for the U nited States is significant and definitely in the p ublic
interest.

Type Certification without FIKI is not a commercially viable option due to the operational needs of the c orporate aircraft market. Similarly, airplane performance rest rictions are not a commercially viable option and wou ld be highly punitive to GALP’s ability to compete in the marketplace, at best.

Adequate time is needed to develop the appropriate m itigations and system features to address this concern. This will involve software modifications to the engine FADEC and WAI System control which require a long lead-time to assure proper functionality and software compliance. System changes are required to critical engine and aircraft control systems which must be car efully done to not introduce additional or unexpect ed
hazards to these controls.

GALP is responding in a timely fashion to this issue whi ch, as stated above, only became known during
recent FAA FSB activities. This is a crucial time in th e development and certification of the Gulfstream G 280. A delay in granting this exemption would be detrime ntal to GALP by delaying the Type Certification and delivery of the product.

In Conclusion:

Respectfully, GALP will appreciate FAA’s early consid eration and grant of the requested exemption as requested to support final Type Certification efforts and delivery of aircraft to our customers as scheduled.

GALP believes early consideration without a delay for public comment is warranted due to the conservative mitigation offered for the interim period of the ex emption, that an acceptable level of safety is establi shed and because an urgent need exists with regard to timely Typ e Certification of the Gulfstream G280.