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 

### 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

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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

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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.