ST Aerospace Mobile, Inc 2100 9th Street, Brookley Complex Mobile, Alabama 36615, USA Tel : (251) 438 8888 Fax : (251) 438 8892

Singapore Technologies Engineering Page 1 of 4 FAA Atlanta 15 th December, 2011
Subject: Petition for Exemption
Reference: FAA Project Number ST13005AT-T

Dear Mr. Avella,

ST Aerospace Mobile (STA Mobile) is the app licant for a multiple airplane Supplemental Type Certificate (STC) for conversion of Boeing 757-200 passenger airplanes into an “8 pallet/80-passenger” Combi configuration under FAA Project Number ST13005A T-T. STA Mobile expects issuance of STC by
the end of 2011.

STA Mobile respectfully submits this letter to petition for an exemption for § 25.783(c) and § 25.783(d)(3)(i), to allow the current Main Deck Cargo Door (MDCD), part number 65-25326-90710 which was approved under STC ST03562AT for the STA Mobile 757-200SF conversion, to be used for the STA Mobile 757-200 Combi configuration.

STA Mobile requests that the publication and co mment procedures be waived in accordance with § 11.29 and § 11.87 for the following reasons: i. The FAA had approved the MDCD for STC ST03562AT (STA Mobile 757-200SF) ii. The FAA clarified the requirements of § 25.783(c) and § 25.783(d)(3)(i) late in the STC certification program iii. This time-limited exemption is temporary, and STA Mobile must implement design changes to meet the requirements of § 25.783 Amendment 25-114. iv. Further delay of STC issuance would increas e the harm to STA Mobile’s follow-on business and delay Combi conversions of airplane nec essary to support NATO relief operations.

DESCRIPTION OF CONVERSION

The STA Mobile 757-200 Combi configuration is der ived from the STA Mobile 757-200SF certified by
STC ST03562AT. The combi modification is similar to that of the STA Mobile 757-200SF except that the forward main deck cabin aft of the Rigid Cargo Barrier (RCB) will be converted to a Class C Main Deck Cargo Compartment (MDCC) and the main deck cabin aft of Station 1119 approximate is retained with minorSingapore Technologies Engineering Page 2 of 4 modifications to accommodate 80 passengers and up to 3 flight attendants separat ed from the MDCC by a
smoke barrier. The MDCD identical to the STA Mobile 757-200SF forms part of the MDCC.

DESCRIPTION OF THE ISSUE

STA Mobile’s intention for project ST13005AT-T wa s to reuse the design of the MDCD that was approved in STC ST03562AT and in the Boeing 757-200 Special Freighter. This design has been
evaluated and it meets and exceeds the requirements of § 25.783 Amendm ent 25-88. However, because § 21.101 requires that a “changed product complies with the airworthiness requirements applicable to the category of the product in effect on the date of t he application for the change”; the MDCD must now meet the requirements of § 25.783 Amendment 25-114. As explained below there are three requirements from
Amendment 25-114 that the MDCD does not meet. Due to some confusion over the original approval basis, this issue was only raised by the FAA late in the program. Thus, STA Mobile had proceeded in good faith with the understanding that the existing MDCD design would meet the certification basis for this program. STA Mobile has already modified one airplane and having to make design changes at this time will further delay the delivery of the modifi ed airplane and expose STA Mobile to a significant financial penalty. It is STA Mobile’s intention to make the appropriate design changes to the MDCD to ensure that it meets the requi rements of § 25.783 Amendment 25-114 for which we are asking an exemption to. However, STA Mobile needs time to develop these design changes.

STA Mobile determined that the MDCD does not meet these requirements from § 25.783 at
Amendment 25-114:

1. The MDCD has two vent pressure doors loca ted on the lower half of the door and are hinged inward-opening. The vent pressure doors are open until the latches are fully closed. The hinge fittings of each pressure door have st op locks, which engage the latches to preclude closure of the pressure doors until all four pairs of latches are in fully latched position. Conversely, the latches cannot be rotated to the open position until the pressure doors are open. If they are not latched, the pressure doors cannot close. This will prevent pressurization of the airplane to an unsafe leve l if the MDCD is not fully closed, latched, and locked. However, the pressure doors can clos e as soon as the latches are in their fully latched position. They do not monitor the latch and lock condition as required by § 25.783(c).Singapore Technologies Engineering Page 3 of 4 2. There is one latch lock per pair of latch on the MDCD, and not an individual lock for each
latch as required by § 25.783(d)(3)(i).

3. The MDCD has view ports which only show that the MDCD is latched and do not provide an adequate view of the locks . The MDCD does not meet the r equirements of § 25.783(f). This requirement is not part of the exempti on request. ST Aerospace will be requesting an exception to this requirement per CFR 21.101.

There are 79 757-200 Production Freighters, 34 757-200 Special Freighters and 1 Combi Freighter produced by Boeing, that have the identical MDCD installed. As of today, these aircraft have accumulated more than 2,740,360 fli ght hours and 1,885,412 flight cycles without any significant service difficulties. Service history in formation is attached separately.

To date, STA Mobile has re-delivered fort y-seven (47) STA Mobile 757-200SF configured airplanes since the issuance of STC ST03562AT on April 2, 2008 and the MDCD has accumulated a considerable satisfactory service history.

EVALUATION OF PUBLIC INTEREST:

Granting this petition is in the public interest because:

• It allows adequate time for STA Mobile and its supplier to develop an effective design solution to ensure that the new design meets the latest Amendment level. STA Mobile
needs the time to ensure that the new desi gn is robust and that it will not introduce unintended consequences.

• It will also allow the modified airplane to return to service. The airplane will be used in support of NATO operations starting in January 2012.

• It will raise the safety level of the airline fleet because airlines will have to replace the Boeing 757-200s that are modified to Combis with new airplanes that meet newer 14
CFR Part 25 Amendments.

• It will help in the reduction of air pollu tion because Combi-configured airplanes will optimize the space usage in flights in case s where there is a low demand in passenger flights and a high demand in cargo transportati on thus reducing the number of flights.