ST Aerospace Mobile, Inc

2100 9th Street, Brookley Complex

Mobile, Alabama 36615, USA

Tel : (251) 438 8888

Fax : (251) 438 8892

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FAA Atlanta 09

th May 2014

Subject: Petition for Exemption

Reference: FAA Project Number ST14446AT-T

Dear Mr. Avella,

ST Aerospace Mobile (STA Mobile) is the applicant for a multiple airplane Supplemental Type 

Certificate for conversion of Boeing 757-200 passenger airplanes to a 15-Unit Load Device (ULD) position 

(15-P) freighter configuration under FAA Project Number ST14446AT-T. STA Mobile expects issuance of 

STC by October 15, 2014.

The purpose of this letter is to petition for an exemption from the requirements of certain sections 

of Title 14, Code of Federal Regulations (14 CFR), Part 25, to allow carriage of non-crewmembers, or 

‘supernumerary’ personnel, in a compartment within the reconfigured flight deck on the converted 

airplanes. Supernumeraries will be restricted to those persons complying with § 121.583 (a)(1) through 

(a)(8). 

STA Mobile requests that the publication and comment procedures be waived in accordance with 

§ 11.29 and § 11.87 for the following reasons:

i. Similar exemptions have been issued by the FAA for STC ST03562AT (STA Mobile 757-

200SF), Boeing 757-200PF & STC ST01529SE (Precision Conversions’ 757-200PCF)

ii. Granting this petition would not set a precedence

DESCRIPTION OF CONVERSION

The main features of the intended conversion from the passenger aircraft configuration include:

(a) Installation of a side-opening main deck cargo door (MDCD) and its surround structure. The MDCD 

design is based on that used in the STA Mobile 757-200 Combi Freighter (STC ST03952AT) 

construction.

(b) Installation of a 9g rigid cargo barrier (RCB) at approximately STA 335, identical to that in the Boeing 

757-200PF “package freighter (“PF”)” design, providing separation between the flight deck and the 

main deck cargo compartment.
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(c) Installation of a vendor-developed main deck cargo loading system (CLS) to accommodate 15 

industry-standard 88 X 125 contoured ULDs, such as the International Air Transport Association 

(IATA) SAA container, on the main deck, using a floor track system based on, and modified from, 

the incoming passenger aircraft main deck seat track installation, similar to the Boeing 757-200PF 

“package freighter” design.

(d) Accommodation for six in the flight deck, with two pilots and two observers being accommodated 

within the original flight deck layout of the incoming passenger configuration aircraft (with observers 

on bulkhead-mounted seats), and two supernumerary personnel located just forward of the RCB, 

identical to the Boeing 757-200PF package freighter configuration.

(e) Installation of a new crew entry door (CED), identical to that of the Boeing 757-200PF, centered at 

approximately STA 311 on the left-hand side of the fuselage forward of the RCB, in place of the 

forward passenger and service doors existing on the incoming passenger configuration aircraft.

(f) Structural modifications related to the installation of the MDCD, CED, RCB, and CLS, including, but 

not necessarily limited to, the floor and fuselage monocoque (skinframe- stringer) structures.

(g) Systems modifications related to the air conditioning, communications, electrical power, fire 

protection, flight controls, hydraulics, indicating and recording, lighting, pitot-static (navigation), 

oxygen, as well as water and waste handling, based on the 14-P special freighter design, to enable 

the main deck cargo compartment to meet the Class E cargo compartment classification 

requirements, with a one-minute smoke detection system.

(h) Interior modifications and installations related to side-wall and ceiling liners, new flight deck lavatory

and emergency equipment.

(i) Retention of all certificated flight performance as well as weight and balance limitations (maximum 

taxi weight, maximum take-off weight, maximum zero fuel weight, maximum landing weight and 

centre of gravity range) of the incoming passenger configuration aircraft.

(j) Damage tolerance based structural maintenance inspections featuring a minimum of 20,000 cycles 

since modification for initial threshold for new structures, and no less than 3,000 cycles between 

inspections using detail visual inspection as basis, for modified, new and affected structures, to be 

listed as Airworthiness Limitation Items in the Maintenance Planning Data document and its 

supplement.
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Figure 1 – Overview of Post-Conversion STA Mobile 757-200 15-P Freighter

Figure 2 – Post-conversion Flight Deck Layout

Legends

1. Existing Pilot’s Seat

2. New Observer’s Seat

3. New Double Attendant Seat (Added)
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This petition seeks relief from the requirements of the following sections of 14 CFR, for the 15P

conversion:

 § 25.785(j), Amendment 25-88,Seats, berths, safety belts, and harnesses

 § 25.807(g)(1)(i)(1), Amendment 25-114, Emergency Exits

 § 25.812(e), Amendment 25-128, Emergency Lighting

 § 25.813(b)(1)(6), Amendment 25-128, Emergency Exit Access

 § 25.1445(a)(2), Amendment 25-0, Equipment Standards for the Oxygen 

Distributing System

 § 25.1447(c)(1), Amendment 25-116, Equipment Standards for Oxygen 

Dispensing Units

The following information is provided to support this petition:

To date, there have been many passenger-to-freighter conversions being carried out by the 

industry and the reconfigured flight deck layout design has accumulated a considerable satisfactory

service history. 

In accordance with § 121.583, all persons that may be carried on the flight deck will have special 

training, which includes proper methods for egress from the airplane and use of emergency equipment.

Limitations will be imposed on the airplane operator to find that all occupants are physically able to use the 

escape means provided. When supernumeraries are carried, they will be briefed prior to each flight as to 

the location and use of the emergency egress equipment and the supplemental oxygen equipment.

Supernumeraries are also prohibited from being in the cargo area during any flight operation. These 

limitations will be included as part of the Airplane Flight Manual Supplement (AFMS) similar to that of STC 

ST03562AT.

The RCB sliding door will be closed and locked prior to taxi and will not be opened again for 

access to the cargo area until the airplane has parked at its destination. Steps will also be taken to ensure 

that no one is in the cargo area prior to the locking of the sliding door before taxi. 

Occupancy of the flight deck area of the 15P-configured airplane is limited to a total of six (6) 

persons, which will consist of supernumeraries as defined by § 121.583 (a)(1) through (a)(8), and 

personnel permitted on the flight deck as defined by § 121.547. This limitation will be included in the 

AFMS similar to that of STC ST03562AT. 
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The AFMS will include a requirement for the flight crew to brief supernumeraries on use of the 

escape provisions prior to each flight.

§ 25.785(j), Amendment 25-88, “If the seat backs do not provide a firm handhold, there must be a 

handgrip or rail along each aisle to enable persons to steady themselves while using the aisles in 

moderately rough air.”

Justification:

Hand holds are not available in the flight deck area due to the space constrain. The configuration 

of the flight deck area with the supernumerary seats’ backs attached on the RCB as shown in 

Figure 2 does not permit using the seat back as the traditional handhold. The lack of handhold is 

identical to that of STA Mobile 757-200SF supernumerary area configuration. 

A Petition for Exemption was submitted by STA Mobile in connection with the STA Mobile 757-

200SF with regards to the equivalent § 25.785(d) at Amendment 25-32, and this resulted in FAA 

Grant of Exemption No. 9487.

The flight crew area is limited to the use of operator assigned supernumeraries or flight crew (not 

public passenger) as described by § 121.583 (a)(1) through (a)(8) and/or § 121.547 who have 

higher level of training and knowledge of the flight deck area layout. There will also be a 

recommendation to supernumeraries to remain seated with their seat belts fastened. Therefore, 

an acceptable level of safety is provided.

§ 25.807(g)(1)(i)(1), Amendment 25-114, “25.807(g)(1): For a passenger seating configuration of 1 

to 9 seats, there must be at least one Type IV or larger overwing exit in each side of the fuselage or, 

if overwing exits are not provided, at least one exit in each side that meets the minimum dimensions 

of a Type III exit.

25.807(i)(1): Ditching emergency exits for passengers. Whether or not ditching certification is 

requested, ditching emergency exits must be provided in accordance with the following 

requirements, unless the emergency exits required by paragraph (g) of this section already meet 

them:

(1) For airplanes that have a passenger seating configuration of nine or fewer seats, excluding pilot 

seats, one exit above the waterline in each side of the airplane, meeting at least the dimensions of a 

Type IV exit.
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Justification:

Flight deck is equipped with a left hand crew entry door (22" x 56"), with a step-up inside the 

aircaft of 10 inches. This meets the size requirement of a Type III door for the LH side of the 

aircraft. The RH side of the aircraft does not have a Type III door. However, the right hand flight 

deck window will be modified to be openable from the outside to serve as a flight crew emergency

exit. Both exits are above the waterline, and will be equipped with ropes to serve as escape 

means. Recommended evacuation procedures will be briefed to the supernumeraries prior to 

each flight. Since the supernumeraries have a higher level of training and knowledge of the 

airplane configuration than a typical passenger, an acceptable level of safety is provided.

The same exemption was granted to the Boeing Package Freighter certified under TCDS A2NM, 

using Exemption No. 4808, and to Precision Conversions’ PCF (STC ST01529SE), using 

Exemption No. 8258, using the same justifications.

§ 25.812(e), Amendment 25-128, “Floor proximity emergency escape path marking must provide 

emergency evacuation guidance for passengers when all sources of illumination more than 4 feet 

above the cabin aisle floor are totally obscured. In the dark of the night, the floor proximity 

emergency escape path marking must enable each passenger to--

(1) After leaving the passenger seat, visually identify the emergency escape path along the cabin 

aisle floor to the first exits or pair of exits forward and aft of the seat; and

(2) Readily identify each exit from the emergency escape path by reference only to markings and 

visual features not more than 4 feet above the cabin floor.”

Justification:

From Figure 2, the configuration of the converted Boeing Model 757-200 in the flight deck area 

does not provide floor proximity emergency lightings, as required by § 25.812(e). 

The proximity of the two supernumeraries to the emergency exits, via the left hand Crew Entry

Door and the right hand flight deck window, provides a level of safety that would not be enhanced 

by the installation of floor proximity emergency lightings. In addition, supernumeraries have a 

higher level of training and knowledge of the emergency exit layout than the typical passenger. 

Hence, the configuration of the flight deck area provides an acceptable level of safety for the 

supernumeraries.
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The absence of floor proximity emergency exit path marking is identical to the configuration of 

STA Mobile 757-200SF. A Petition for Exemption was submitted by STA Mobile for STA Mobile 

757-200SF and resulted in FAA Partial Grant of Exemption (No. 9487). In Exemption No. 9487, 

The FAA had granted the exemption based on the same justifications described above. The same 

exemption was granted to Precision Conversions’ PCF (STC ST01529SE), using Exemption No. 

8258, based on the same justifications.

§ 25.813(b), Amendment 25-128, “Adequate space to allow crewmember(s) to assist in the 

evacuation of passengers must be provided as follows:

(1) Each assist space must be a rectangle on the floor, of sufficient size to enable a crewmember, 

standing erect, to effectively assist evacuees. The assist space must not reduce the unobstructed 

width of the passageway below that required for the exit.

(6) There must be a handle, or handles, at each assist space, located to enable the crewmember 

to steady himself or herself: 

(i) While manually activating the assist means (where applicable) and, 

(ii) While assisting passengers during an evacuation.”

Justification:

The configuration of the flight area does not provide an assist space adjacent to each exit, due to 

the space constrain within the flight deck. However, since the supernumeraries will have a higher 

level of training than a typical passenger, they will have no need for crew assistance. In addition, 

in the relatively small confines of the flight deck area, the flight crew can easily provide instructions

and some physical assistance to the supernumeraries, if needed.

The absence of an assist space adjacent to each exit is identical to the configuration of STA 

Mobile 757-200SF. A Petition for Exemption was submitted by STA Mobile for STA Mobile 757-

200SF and resulted in FAA Partial Grant of Exemption (No. 9487). In Exemption No. 9487, The 

FAA had granted the exemption based on the same justifications described above. The same 

exemption was granted to the Boeing Package Freighter certified under TCDS A2NM, using 

Exemption No. 4808, and to Precision Conversions’ PCF (STC ST01529SE), using Exemption 

No. 8258.
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§ 25.1445(a)(2), Amendment 25-0, “When oxygen is supplied to both crew and passengers, the 

distribution system must be designed for either--

(1) A source of supply for the flight crew on duty and a separate source for the passengers and 

other crewmembers; or

(2) A common source of supply with means to separately reserve the minimum supply required by 

the flight crew on duty.”

Justification:

There is no means to separate the means of oxygen to reserve the minimum supply required by

the flight crew as the supernumeraries occupy the same flight deck area as the flight crew. Since 

the two supernumeraries are co-located within the enlarged cockpit, they can communicate 

directly and receive instructions from the flight crew. Moreover, the common oxygen cylinder is 

able to supply sufficient supplemental emergency oxygen for up to six occupants for an ETOPS 

duration of up to 120 minutes.

The absence of the ability to separate the oxygen supply for the flight crew use is identical to that 

on the Boeing 757-200 Package Freighter certified under TCDS A2NM and the Precision 

Conversions’ PCF (STC ST01529SE). In Exemption No. 8258, The FAA had granted the 

exemption based on the same justifications described above.

§ 25.1447(c)(1), Amendment 25-116, “There must be an oxygen dispensing unit connected to 

oxygen supply terminals immediately available to each occupant wherever seated, and at least 

two oxygen dispensing units connected to oxygen terminals in each lavatory. The total number of 

dispensing units and outlets in the cabin must exceed the number of seats by at least 10 percent. 

The extra units must be as uniformly distributed throughout the cabin as practicable. If certification 

for operation above 30,000 feet is requested, the dispensing units providing the required oxygen 

flow must be automatically presented to the occupants before the cabin pressure altitude exceeds 

15,000 feet. The crew must be provided with a manual means of making the dispensing units 

immediately available in the event of failure of the automatic system.”

Justification:

The two supernumeraries will have two quick-donning type masks similar to the flight crew that 

are not automatically presented. However, the high level of training of the supernumeraries and 

the aural warning system will allow the flight crew to command the supernumeraries to don the 
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masks, providing an adequate level of safety to all occupants. The lavatory will also be outfitted 

with a portable walk around oxygen bottle equipped with an oxygen mask. This area will not be 

utilized for takeoff and landing.

The absence of the automatic presentation of the dispensing units for oxygen use is identical to 

the configuration of STA Mobile 757-200SF. A Petition for Exemption was submitted by STA 

Mobile for STA Mobile 757-200SF and resulted in FAA Partial Grant of Exemption (No. 9487). In 

Exemption No. 9487, The FAA had granted the exemption based on the same justifications 

described above. The same exemption was granted Precision Conversions’ PCF (STC 

ST01529SE), using Exemption No. 8258, based on the same justifications.

Evaluation of Public Interest: 

The presence of trained personnel on board the airplane when cargo is carried will enhance flight 

safety, which is in the public interest.

Granting this exemption will enhance the utility of the airplane for the operator by ensuring that 

needed cargo management personnel will be available at each flight destination. This will reduce shipping 

costs and transit time, which is in the public interest

As Boeing 757-200 passenger airplanes are converted into 15P-configured airplanes, airlines will 

replace them with new passenger airplanes which meet newer 14 CFR Part 25 Amendments. Over time, 

this will have the effect of raising the safety level of the passenger airline fleets, which is in the public 

interest.

Petition for Exemption

Based on the information provided, STA Mobile, hereby petitions for exemption from the following 

sections of 14 CFR Part 25 for Boeing 757-200 passenger airplanes converted to a 15P configuration 

under FAA STC Project ST14446AT-T to allow the carriage of supernumeraries in the flight deck area: 

 § 25.785(j), Amendment 25-88,Seats, berths, safety belts, and harnesses

 § 25.807(g)(1)(i)(1), Amendment 25-114, Emergency Exits

 § 25.812(e), Amendment 25-128, Emergency Lighting
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 § 25.813(b)(1)(6), Amendment 25-128, Emergency Exit Access

 § 25.1445(a)(2), Amendment 25-0, Equipment Standards for the Oxygen 

Distributing System

 § 25.1447(c)(1), Amendment 25-116, Equipment Standards for Oxygen 

Dispensing Units

STA Mobile respectfully requests favorable FAA consideration of this petition.

Sincerely,

Kumaresan SUBRAMANIAM 

Engineering Director

ST Aerospace Mobile, Inc.

Office: (251)436-0186

E-mail: Kumaresan_SUBRAMANIAM@stmae.com