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 

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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 requesting 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 request 

that the original petition dated May 17, 2012 be removed from this docket and replaced with this submittal

accordingly. 

- 14 CFR §25.901(b)(2) as amended by Amendment 25-46 

- 14 CFR §25.903(d)(2) as amended by Amendment 25-100 

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

- 14 CFR §25.1301(c) and (d) effective February 1, 1965 

- 14 CFR §25.1305(c)(1) as amended by Amendment 25-115 

- 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 indication 

requirements which apply to the Gulfstream G280 airplane and installed Honeywell AS907-2-1G engines. 

GALP also requests FAA’s early consideration of a grant 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 amendments as referenced above): 

Sec. 25.901 

Installation. 

... 

(b) For each powerplant-- ... 

(2) The components of the installation must be constructed, 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 engine 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 

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(2) The powerplant systems associated with engine control 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 service. 

Sec. 25.939 

Turbine engine operating characteristics. 

(a) Turbine engine operating characteristics must be investigated in flight to determine that no adverse 

characteristics (such as stall, surge, or flameout) are present, to a hazardous degree, during normal and 

emergency operation within the range of operation limitations 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 for 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 addition to the powerplant instruments required by paragraph (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 the crew to unsafe system operating conditions, and to 

enable them to take appropriate corrective action. Systems, controls, and associated monitoring and warning

means must be designed to minimize crew errors which could 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 and damage from external sources. 

(2) The probability of multiple failures and undetected failures. 

(3) The resulting effects on the airplane and occupants, considering the stage of flight and operating conditions, 

and 

(4) The crew warning cues, corrective action required, and the capability of detecting faults. 

Sec. 25.1322 

[Warning, caution, and advisory lights.]

[If warning, caution, or advisory lights are installed in the cockpit, they must, unless otherwise approved by the 

Administrator, be-- 

(a) Red, for warning lights (lights indicating a hazard which may require immediate corrective action); 

Background, Reasons for Exemption and Supportive Information: 

This exemption, if granted, would permit relief from certain engine installation, limitation, operational and 

indication requirements for the Gulfstream G280 where 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-limited to two (2) years to allow improvements presently 

in development to be completed and implemented into the G280 fleet. Improvements now in-work include 

optimized aircraft and engine control system and indication software designed to preclude the possibility of an 

engine ITT exceedance indication during certain high-bleed 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 

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The Gulfstream G280 is nearing the conclusion of a Type Certification effort begun by initial application on 

March 30, 2006 and as extended by FAA agreement through September 30, 2012. Provisional Type 

Certificate number A61NM was granted on March 1, 2012. 

 

An operational review of the Wing Anti-Ice System (WAI System) during recent FAA FSB flight and training

activities has indicated possible compliance issues with the above cited rules. There is an extremely remote 

risk that an ITT exceedance warning message might occur during the initial wing warm-up phase of WAI 

System operation under certain conditions. Engine bleed demands during this phase and the current FADEC 

ITT limits may lead to an indication of engine ITT exceedance to the flight crew. However, the engine is 

actually certified to a higher value (955°C continuous, 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 to the engine or continued safe flight of the aircraft. 

This condition may exist at high power settings, following WAI System activation and until the wing approaches 

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 exceedance 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 by 

as much as 27°C. The planned changes include improved airframe / engine integration functionality by 

optimizing the bleed-demand / engine response and indication functions during WAI System activation, warmup and operation. 

As a precautionary measure, GALP has also assessed the possibility 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 indication 

error event is therefore mitigated as well. 

For such an actual exceedance all of the following conditions, 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 to 

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 System 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 reaching exceedance values during operation. 

GALP respectfully submits this petition for a time-limited 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 integration design and further preclude the risk of an occurrence of 

the described exceedance warning indication. GALP anticipates that these changes will be available by the 

end of 2013, and will make every effort to ensure that 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 high-usage rate for a Gulfstream Mid-Cabin airplane is 

about 600 hours per year, and that a more typical usage rate is approximately 400 hours per year. Given the 

limited time-frame for the requested exemption and considering the operational window for the airplanes 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 thereby would have more margin to an ITT limit than a fully 

deteriorated engine as used in the margin analysis. The limited number of airplanes that will be delivered 

within the two-year period of the requested exemption represents a negligible addition to overall fleet 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 

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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 impractical to demonstrate full compliance through aircraft or 

other system limitations or by system level changes with 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 engine FADEC software within a workable time-frame. 

Type Certification of the Gulfstream G280 to include Flight Into Known Icing (FIKI) is vital to the product. 

Restricting the operational envelope in this manner, or in any form that otherwise restricts airplane 

performance is commercially unviable for GALP and its customers and would be very detrimental to the 

marketability of this aircraft. 

Information Supporting Exemption: 

GALP offers the following justification and substantiation for granting this time limited exemption and as to how 

the current type design provides an acceptable level of safety. It should be pointed out that the potential for an 

ITT exceedance warning indication only exists as an extremely remote possibility. 

GALP, with assistance from the engine manufacturer, has established that tolerance against the risk of the 

described exceedance occurring is related to engine ‘margin’, e.g. a newly-delivered engine has greater ITT

temperature margins than an ‘end of life’ engine. Airplanes 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 airplane usage rates. This mitigates any exposure to the 

condition, should AFM procedures not be followed, as these margins help offset the likelihood of a high-bleed 

rate condition driving such an occurrence. 

Current aircraft ITT engine limits are below the certified engine ITT limits by as much as 27 degrees. Even if a 

momentary engine ITT exceedance is seen during the brief period of time while the wing anti ice system 

heats up the wing, the engine is certified to a higher value than the airframe exceedance indication as stated 

above (955°C continuous / 970°C maximum for 20 seconds 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 immediate action, as required. Such action would be 

consistent with a message of this type being generated by any other cause and is therefore functionally within 

the reasonable scope of operation. 

GALP’s assessment of the possibility of an actual operational ITT exceedance event during foreseeable flight 

conditions has also shown the likelihood of such an actual ITT exceedance occurring during foreseeable fleet 

operations to be extremely remote. Therefore the risk of an actual exceedance occurring during an indication 

error event is mitigated. 

The limited number of airplanes that will be delivered within the two-year period of the requested exemption 

represents a negligible addition to overall fleet risk. 

Normal operational procedures provide ample means by which the crew may avoid the operational issue of an 

ITT exceedance indication. The condition of this exemption will be also be appropriately stressed during pilot 

type rating and training activities in the Gulfstream G280 so as to ensure crew awareness of the extremely 

remote potential for an exceedance warning. 

GALP will design, certify and incorporate into Gulfstream G280 production line and existing fleet, a series of 

modifications required to demonstrate compliance with the requirements of the above listed rules within the 

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 conditions 

that must be present. Analysis of foreseeable fleet operations, the attending risks of an occurrence / icing 

event and related operational actions, Airplane Flight Manual (AFM) procedures (including prohibition against 

operation in WAI System auto-mode) and reliability of 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 

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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 failures 

that could cause Uncommanded activation of WAI are extremely 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 check be performed at “A check” at 500 hours, or “C check” 

at 12 months, whichever comes first. This is to ensure that appropriate ITT margins are maintained in-service. 

The MMEL will prohibit single bleed source dispatch or other dispatch configuration limitations which are 

fundamental to the exemption being requested. 

Public Interest / Benefit: 

GALP offers the following reasons for why granting the requested time-limited exemption is in the public 

interest, as required by 14 CFR 11.81: 

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

Gulfstream G280. While these airplanes are not manufactured in the U.S., a significant portion of the airplane, 

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

exemption 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 contrary to the public interest. 

Granting this exemption would permit the efficient transport of employees, corporate executives and important 

clientele in an efficient and safe environment. Due to the high demand for these corporate aircraft, it is 

imperative that the petitioner is granted the regulatory relief requested. Failure to achieve this goal will result in 

delivery delays and the potential for significant loss of 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 United States is significant and definitely in the public 

interest. 

Type Certification without FIKI is not a commercially viable option due to the operational needs of the corporate 

aircraft market. Similarly, airplane performance restrictions are not a commercially viable option and would be 

highly punitive to GALP’s ability to compete in the marketplace, at best. 

Adequate time is needed to develop the appropriate mitigations 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 carefully done to not introduce additional or unexpected 

hazards to these controls. 

GALP is responding in a timely fashion to this issue which, as stated above, only became known during 

recent FAA FSB activities. This is a crucial time in the development and certification of the Gulfstream G280. 

A delay in granting this exemption would be detrimental to GALP by delaying the Type Certification and 

delivery of the product. 

In Conclusion: 

Respectfully, GALP will appreciate FAA’s early consideration 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 exemption, that an acceptable level of safety is established and 

because an urgent need exists with regard to timely Type Certification of the Gulfstream G280.