FAA Atlanta 24

th Oct 2014

Subject: Petition for Exemption

Reference: FAA Project Number ST14446AT-T

Dear Mr. Avella,

VT Mobile Aerospace Engineering, Inc. (VT MAE) 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. 

VT MAE 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 noncrewmembers, 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). 

VT MAE 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 (VT MAE 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 VT MAE 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.
Page 2

(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.
Page 3

Figure 1 – Overview of Post-Conversion VT MAE 757-200 15-P Freighter

Figure 2 – Post-conversion Flight Deck Layout
Page 4

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

 § 25.810(a)(1), Amendment 25-114, Emergency egress assist means and 

escape routes

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

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

 § 25.857(e), Amendment 25-93, Cargo Compartment Classification

 § 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 
Page 5

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. 

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 VT MAE 757-200SF supernumerary area configuration. 

A Petition for Exemption was submitted by VT MAE in connection with the VT MAE 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:
Page 6

(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.

Justification:

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

aircraft 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.

§ 25.810(a)(1), Amendment 25-114, “(a) Each non over-wing Type A, Type B or Type C exit, 

and any other non over-wing landplane emergency exit more than 6 feet from the ground with 

the airplane on the ground and the landing gear extended, must have an approved means to 

assist the occupants in descending to the ground.

(1) The assisting means for each passenger emergency exit must be a self-supporting slide or 

equivalent; and, in the case of Type A or Type B exits, it must be capable of carrying 

simultaneously two parallel lines of evacuees. In addition, the assisting means must be 

designed to meet the following requirements--

(i) It must be automatically deployed and deployment must begin during the interval between 

the time the exit opening means is actuated from inside the airplane and the time the exit is 

fully opened. However, each passenger emergency exit which is also a passenger entrance 

door or a service door must be provided with means to prevent deployment of the assisting 

means when it is opened from either the inside or the outside under nonemergency conditions 

for normal use.

(ii) Except for assisting means installed at Type C exits, it must be automatically erected within 

6 seconds after deployment is begun. Assisting means installed at Type C exits must be 
Page 7

automatically erected within 10 seconds from the time the opening means of the exit is 

actuated.

(iii) It must be of such length after full deployment that the lower end is self-supporting on the 

ground and provides safe evacuation of occupants to the ground after collapse of one or more 

legs of the landing gear.

(iv) It must have the capability, in 25-knot winds directed from the most critical angle, to deploy 

and, with the assistance of only one person, to remain usable after full deployment to 

evacuate occupants safely to the ground.

(v) For each system installation (mockup or airplane installed), five consecutive deployment 

and inflation tests must be conducted (per exit) without failure, and at least three tests of each 

such five-test series must be conducted using a single representative sample of the device. 

The sample devices must be deployed and inflated by the system's primary means after being 

subjected to the inertia forces specified in Sec. 25.561(b). If any part of the system fails or 

does not function properly during the required tests, the cause of the failure or malfunction 

must be corrected by positive means and after that, the full series of five consecutive 

deployment and inflation tests must be conducted without failure.” 

Justification:

The crew entry door (CED), which is also used as an emergency exit, will not incorporate a 

self-supporting, automatically deployed and erected slide. In place of such a device, inertia 

reel descent devices will be installed in close proximity to the CED, in addition to an escape 

rope provision directly above the CED upper sill, which will be used in an emergency landing 

event. Such inertia reel descent devices have been previously permitted for use in Boeing 

757-200PF & 767-300F airplanes. Incorporating inertia reel descent devices and harnesses 

will provide a means of emergency egress at the crew entry door which is common to that of 

the Boeing 757-200PF & 767-300F. The use of such inertia reels and harnesses provide at 

least an equivalent level of safety to that provided by an escape slide. A flight deck evacuation 

procedure will be included in the Airplane Flight Manual Supplement for the use of ropes / 

lanyards when exiting the airplane through the flight deck windows. The Supplement will also 

include the requirements for the specific techniques for emergency egress to be briefed to 

non-crew occupants before each flight. Placard(s), to indicate the usage of the inertia reel 

devices, will be installed next to the inertial reel devices.

The same exemption, using inertia reel descent devices, was granted to the Boeing Package 

Freighter certified under TCDS A2NM, using Exemption No. 4808A, and to Precision 

Conversions’ PCF (STC ST01529SE), using Exemption No. 8258, with the same justifications.
Page 8

§ 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.

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, 
Page 9

(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 VT 

MAE 757-200SF. A Petition for Exemption was submitted by VT MAE for VT MAE 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.

§ 25.857(e), Amendment 25-93, “(e) Class E. A Class E cargo compartment is one on 

airplanes used only for the carriage of cargo and in which--

(1) [Reserved]

(2) There is a separate approved smoke or fire detector system to give warning at the pilot or 

flight engineer station;

(3) There are means to shut off the ventilating airflow to, or within, the compartment, and the 

controls for these means are accessible to the flight crew in the crew compartment; 

(4) There are means to exclude hazardous quantities of smoke, flames, or noxious gases, 

from the flight crew compartment; and

(5) The required crew emergency exits are accessible under any cargo loading condition.”

Justification:

Class E cargo compartments are usually remote from the flight deck and encompass the 

entire interior of the airplane. The means of controlling fires that might occur in the cargo 

compartment is to starve the fire of oxygen. This is accomplished by depressurizing the 

airplane and maintaining an altitude that will not support combustion. For this reason, 

passengers are not permitted on board such airplanes. The two observers & two 

supernumeraries, that the converted airplane is designed to accommodate, will be located in 

the flight deck between the flight crew seats and the rigid cargo barrier (RCB) that separates 
Page 10

the flight deck and the new Class E cargo compartment. This configuration is similar to that of 

the Boeing Package Freighter certified under TCDS A2NM. The FAA has previously granted 

exemptions for carriage of persons in addition to crew on freighter airplanes, provided that 

certain other conditions are met. These conditions have varied, depending on the airplane 

design and the number of persons involved.

In all cases, there must be suitable means of preventing smoke penetration into areas that are 

occupied. The current design accounts for this by providing a barrier which must comply with 

the smoke penetration requirements for the flight deck, in the form of the RCB. Placards are 

installed on the barrier to indicate that the barrier is to be secured and that no personnel are 

allowed into the Class E cargo compartment during flight.

The same exemption, for the permission of accommodating such supernumeraries in an 

airplane containing a Class E cargo compartment, was granted to Precision Conversions’ PCF 

(STC ST01529SE), using Exemption No. 8258.

§ 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.
Page 11

§ 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 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 VT MAE 757-200SF. A Petition for Exemption was submitted by VT 

MAE for VT MAE 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
Page 12

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, VT MAE, 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

 § 25.810(a)(1), Amendment 25-114, Emergency egress assist means and 

escape routes

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

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

 § 25.857(e), Amendment 25-93, Cargo Compartment Classification

 § 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

VT MAE respectfully requests favorable FAA consideration of this petition.

Sincerely,

Kumaresan SUBRAMANIAM 

Engineering Director

VT Mobile Aerospace Engineering, Inc.

Office: (251)436-0186

E-mail: Kumaresan.SUBRAMANIAM@vtmae.com