14MAY2014

U.S. Department of Transportation

Docket Operations

West Building Ground Floor

Room W12-140

1200 New Jersey Ave. SE.

Washington, D.C. 20590

RE: ISPA254T Petition for Exemption: 

Dear Sir/Madam,

Springfield Aircraft Charter & Sales, Inc. respectfully petitions the FAA for 

authorization to deviate from 14 CFR §135.89(b)(3) (Pilot Requirements: Use of 

Oxygen) by establishing equivalent levels of safety operating under 14 CFR 

§121.333 (c)(2)(i)(A) (Supplemental Oxygen for Emergency Descent....)

By granting authorization to Springfield Air to operate under 14 CFR §121.333 

(c)(2)(i)(A), Springfield Air will realize significant savings in on-board oxygen 

duration, thereby enhancing operational safety when conducting extended over 

water/remote missions. This reduction in enroute oxygen use is paramount when 

flight planning extended operations over remote and/or oceanic areas by 

increasing the amount of available oxygen at the Equal Time Point (ETP) for 

cabin depressurization emergencies.

In some cases, the ability to remain at FL250 for extended periods of time, post 

loss of cabin pressure, is mandatory to prevent incurring a wet footprint or for 

terrain clearance requirements in areas of exceedingly high terrain. 

The current Springfield Aircraft fleet make up is such that aircraft system oxygen 

is available to all crew/passengers and the passenger masks are approved for 

continuous use up to FL250. Because of this capability, Springfield Air is able to 

improve overall safety by descending to FL250 (initially) during an aircraft 

depressurization, rather than a continuous descent to 10,000 feet. This strategy

serves two purposes:
• Enhanced terrain separation clearance - there are few geographic areas 

around the world that would penetrate the FL250 capability of our aircraft. 

By limiting the initial descent during a depressurization to FL250, the crew 

is able to regroup and evaluate terrain/obstacle clearance before 

commencing further descent.

• Extended ETP envelope - most 14 CFR 121 Air Carriers plan a descent to 

FL100 after experiencing a depressurization, incurring huge penalties in 

enroute fuel flow and a drastic increase in diversion times as a result. 

Additionally, when conducting oceanic or remote operations, the aircraft is 

now limited in diversion capability due to the low altitude, high fuel flow, 

and resultant low true airspeed. Conversely, Springfield Air’s aircraft are

able to level at FL250, above significant terrain and weather, and hold

higher Mach/true airspeed, thereby reducing diversion times to the alternate 

airport.

The relief from 14 CFR §135.89(b)(3) simply delays, for a short period, the onset 

of single crewmember oxygen depletion while manning the flight deck. 14 CFR

121 aircraft operate predominantly between FL 330-370, whereas corporate 

aircraft are designed to start cruise at FL390-FL410 and continue optimized climb 

schedules to as high as FL510. 

The stark reality is that few corporate aircraft can make designed range profiles 

below FL410, our fleet included. In fact, the GV’s QRH handbook flight planning 

chart (See below) starts at FL390 and continues up to FL490. The difference in 

hourly fuel burn between FL350 and FL450 (See below) is almost 1,000 pounds 

per hour; over a typical 10-12 hour flight its obvious to see the importance altitude 

plays in efficiency and range. 
Illustration Showing Initial Level Off
Illustration Showing Length of Time at Initial Level Off Altitude Below 

FL410
Illustration Depicting Fuel Flow Difference Between FL350 and FL450
Analyzing a mid size, mid range, corporate aircraft conducting a flight from SFOHNL with 6 passengers and 2 crew (oceanic/remote operations) and close to the 

limit of what the aircraft is capable of. The aircraft cannot, under most 

circumstances, descend to FL100 after a depressurization and make land with the 

required reserves, i.e., incurring a wet footprint. Under this scenario, once 

reaching FL100, the aircraft must slow to max range cruise just to make land 

taking roughly 3+51. However, by stopping descent at FL250 to expend on board 

oxygen (120 minutes), then commencing descent to F100 the aircraft easily makes 

land over 1.7 hours sooner, at roughly 2+10. Reducing crew and passenger 

exposure to extended diversion times during emergency situations is paramount to 

a successful (and survivable) outcome to an emergency. See examples belowResults for descent to FL100-

Results for descent to FL250 for 120 minutes-
The significance of this scenario is the fact that prior to reaching FL410, upon 

passing FL350, at least one crewmember must be depleting the oxygen system. 

Under the above scenario, the oxygen reserve (fully serviced bottle) at FL250 is 

approximately 161 minutes (3140 liters of O2), minus what the crew consumes 

prior to the ETP. To prevent a wet footprint scenario, the aircraft must arrive at the 

ETP with approximately 2,640 liters of oxygen (120 minutes at FL250 for 2 crew 

and 6 pax). Estimating an average consumption rate of 3 liters/min (per single 

crew member at a typical pressurized cabin altitude) for the 146 minutes it takes to 

arrive at the ETP and that crewmember has depleted 438 liters of available 

oxygen. Leaving roughly 2702 liters of oxygen remaining (3140 liters of fully 

serviced O2 system). This leaves a difference of only 62 liters of oxygen. Bear in 

mind that these numbers are based on a fully serviced bottle at 1800psi. 

Where relief from 14 CFR §135.89(b)(3) will come into play is by delaying the 

depletion of oxygen until reaching higher flight levels (above FL410). In this case,

we would expect to be above FL350, but below FL410, for approximately 30 

minutes, thereby saving roughly 90 liters of oxygen. 

When we discuss longer-range missions in the GV, where initial level off altitudes 

at high gross weights are below FL410 for, in some cases, several hours, we could 

realize savings of roughly 300-500 liters of oxygen. This is a significant factor in 

mitigating compound emergencies and reducing risk to those on board. By 

complying with 14 CFR §121.333 (c)(2)(i)(A), flight crews will be better prepared 

to deal with a loss of cabin pressure by having the maximum amount of available 

oxygen when it is needed the most - to execute a rapid descent to a safe altitude 

and extend diversion cruise capability at a higher altitude. 

In establishing safety benchmarks, it is also important to note that both fleet 

aircraft types Springfield Air currently operates include an automatic Emergency 

Descent Mode designed to augment/protect the initiation of an emergency descent 

should the crew become incapacitated. Both the GV and CE750, with autopilot 

engaged, will initiate a 90-degree left turn, descending at Vmo/Mmo to 15,000 and 

level off. The following illustrations describe these modes of operation on the 

respective aircraft.
GV Emergency Descent Mode-
CE750 Emergency Descent ModeIt is also important to note the redundancy built into both the GV and CE750 

pressurization systems, which are certified under 14 CFR 25 Transport Category 

Federal regulations (same as 121 air carriers). Both aircraft have two sources of 

engine bleed air, either of which is sufficient to meet the demands of the aircraft.

Additionally, both aircraft are equipped with dual air conditioning packs, each of 

which is capable of supplying sufficient pressurization air in the event one unit 

fails. Both aircraft are equipped with an isolation valve that will allow one engine 

to supply bleed air to both packs in the event of an engine failure, bleed leak, or 

other cause for single source bleed supply. GV Schematic to follow-

Both aircraft are equipped with dual pressure vessel bulkheads between the cabin 

and baggage compartments. If the baggage door seal were to fail, the secondary 

pressure vessel and check valves automatically isolate the baggage compartment 

and maintain normal cabin pressure. CE750 Procedure-
Both aircraft pressurization controllers are triple redundant with an automatic, 

manual, and emergency mode of control that are supplied power from multiple 

redundant sources. 
In terms of warning systems available to advise the flight crew of impending 

failure or increasing cabin altitude both aircraft are equipped with multiple set 

points for both warning and caution messaging, including aural advisories. 

The passenger oxygen system automatically deploys at approximately 13,500 feet, 

and above a cabin altitude of FL370, crew oxygen masks automatically provide 

pressure breathing rather than just 100% oxygen. 

As a result of the multiple levels of redundancy in the pressurization system, one 

of the only means of a truly “rapid” or “explosive” decompression would be a 

significant structural failure of a cabin door, cabin or cockpit window, or failure 

the aluminum skin structure or ribbing. To date, there has never been such a 

failure on either aircraft since their certification in the late 90’s.
Springfield Air’s fleet are also equipped with TSO’d (C78a, C89a, C99a) quick

donning on-demand oxygen masks of the same make/model. More importantly, 

the same operating procedures for both O2 masks are employed. Furthermore, 

these systems are certified under 14 CFR 25, § 25.1441-25.1453, the very same 

regulations Part 121 Air Carrier aircraft are manufactured thereby positively 

establishing equivalent levels of safety. 

Example of Crew Oxygen Masks-
In summation, Springfield Air is not seeking relief from 14 CFR §135.89(b)(3) as 

a means to circumvent Federal regulations, quite the contrary. Due to the diverse 

and complex nature of Springfield Air flight operations, through intense 

operational analysis, it has been deemed vital to flight safety to mitigate oxygen 

depletion to conserve, as much as feasible, emergency oxygen reserves in the 

event an aircraft experiences a loss of cabin pressure and is forced to descend to 

lower altitudes. Springfield Air believes it has demonstrated a valid need for the 

exemption to increase public safety based on analysis and risk 

mitigation/prevention techniques from our Safety Management System analysis. It 

is truly in the interest of public safety that this exemption to adopt 14 CFR 

§121.333 (c)(2)(i)(A) be granted to Springfield Air.

Springfield Air invites comments, questions, and feedback with regard to the 

petition for exemption.

Sincerely yours,

Louie	DeSantis

Assistant	Director	of	Operations
Pursuant	to	the	requirements	of	CFR	14	§11.81-

a) Springfield	Aircraft	Charter	&	Sales	

Air	Carrier	Certificate	ISPA254T

10	NW	Richards	Road,	Suite	108

Kansas	City,	MO	64116

1-888-218-2085

b) 14 CFR §135.89(b)(3)- Pilot Requirements: Use of oxygen “Whenever a 

pressurized aircraft is operated at altitudes above 35,000 feet MSL, at least one 

pilot at the controls shall wear, secured and sealed, an oxygen mask required by 

paragraph (b)(2)(i) of this section”

c) Springfield Air seeks relief from 14 CFR §135.89(b)(3) by establishing equivalent 

levels of safety operating under 14 CFR §121.333 (c)(2)(i)(A) Supplemental 

Oxygen for Emergency Descent and for First Aid “(i) The one pilot need not wear 

and use an oxygen mask at or below the following flight levels if each flight 

crewmember on flight deck duty has a quick-donning type of oxygen mask that the 

certificate holder has shown can be placed on the face from its ready position, 

properly secured, sealed, and supplying oxygen upon demand, with one hand and 

within five seconds:

(a) For airplanes having a passenger seat configuration of more than 30 

seats, excluding any required crewmember seat, or a payload capacity of 

more than 7,500 pounds, at or below flight level 410.”

d) *See supporting material petition above

e) *See supporting material petition above

f) See summary on subsequent page-
Summary for Federal Register (14 CFR §11.81)(f)

Petitioner: Springfield Aircraft Charter & Sales (ISPA254T)

Rule for which exemption sought: 14 CFR §135.89(b)(3)

Springfield Aircraft Charter & Sales is seeking relief from the 14 CFR 

§135.89(b)(3) FL350 oxygen requirement to delay the depletion of the aircraft 

oxygen system until FL410 in accordance with 14 CFR §121.333 (c)(2)(i)(A).

Springfield Aircraft Charter & Sales requests worldwide effectivity for exemption 

since roughly 60% of our flight operations occur outside the continental United 

States, and this exemption is most needed on long-range international missions.