RA-11-03359 Enclosure

Page 1 of 2 Boeing Proposal for Deviation from FAA Partial Exemption No 9943 and Issue Paper ES-13 747-8 Program

Reference a) Exemption No. 9943, “The Boeing Compa ny for an exemption from 25.841(a)(2) and 25.841(a)(3) of Title 14, Code of Federa l Regulations,” dated October 19, 2009 b) FAA IP ES-13 Stage 4, “747-8 Crew a nd Passenger, and 747-8 Freighter (747-8F) Crew and Supernumerary, Oxygen Equipmen t for Use Above 40,000 Feet,” dated April 7, 2011 c) Boeing letter RA-11-02860, “747-8F Boeing Proposal for Emergency Descent Altitude Limitation,” dated June 7, 2011.

Executive Summary On May 16, 2011, Boeing conducted two certification flight test profiles to demonstrate the 747-8 Freighter (747-8F) emergency de scent capability. Per Federal Aviation Administration (FAA) Partial Exemption No 9943 (Reference a), the goal of the test was to show that after decompression due to a ro tor burst event at an airplane indicated operating pressure altitude of 43,000 feet (ft), the cabin pressure alti tude will not exceed 40,000 feet for more than 1 minute and 25,000 ft for more than 3 minutes.

In reference c) Boeing provide d results of two 747-8F certifi cation flight descent profiles showing that at the 3-minute mark, the ai rplane was approximately 900 ft above the 25,000 ft target. Boeing therefor e recommended using the certific ation flight test data to lower the 747-8F maximum operating alt itude limit from 43,100 ft to 42,100 ft commensurate with the approximately 900 ft miss.

Although the partial exemption refers to an ai rplane indicated operati ng pressure altitude of 43,000 ft and the recommended 747-8F airplane operating pr essure altitude will be 42,000 ft (42,100 ft maximum operating pressure altitude), Boeing be lieves that this is an administrative change and therefore a change to the exemption would be of no real value. The important requirement is the time exposur e of the aircraft occupants to pressure altitudes, in this case between the origin al operating altitude and 25,000 ft. Boeing has

demonstrated that the 747-8F meets the tim e exposure requirement by using an airplane maximum operating altitude of 42,100 ft rather than 43,100 ft. However, if the exemption must be revised, Boeing recommends that the certification flight data as

summarized in this letter and fu rther explained in reference c) be used as support for the FAA’s desire to revise Partial Exemption No 9943 to change the referenced maximum operating altitude from 43,000 ft to 42,100 ft.

Similarly, the issue Paper ES-13 (Referen ce b) addressing the use of oxygen over 40,000 ft, notes the 43,000 ft airplane operating altitu de. Boeing recommends that there be no changes to issue paper ES-13 because by limiting the altitude of the airplane to 42,100 ft, the requirements of issue paper ES-13 are met. If issue paper ES-13 must be revised then the only change needed is to revise the 43,000 ft airplane operating altitude to 42,100 ft airplane operating altitude.RA-11-03359 Enclosure

Page 2 of 2 Certification Flight Data Two Boeing 747-8 Freighter certification f lights were conducted on May 16, 2011 per the partial exemption airplane and environmental operational boundaries. Additionally, the test procedure took into account a 17 second in itial crew reaction tim e from the start of the simulated decompression event to comma nded initiation of the rapid emergency descent, so the allotted descent time requi rement to reach the 40,000 ft mark was 43 seconds and the time requirement to r each the 25,000 ft mark was 163 seconds.

The certification flight data shows that both descents were at the 40,000 ft mark in less than 43 seconds. However, both descents missed the 25,000 ft mark by approximately 11 seconds. In further review of the data, at the 163 seconds requirement, both descents were above the 25,000 ft mark by:

 Certification flight test #1: altitude at 163 seconds: 25,891 ft (891 ft exceedance)

 Certification flight test #2: altitude at 163 seconds: 25,932 ft (932 ft exceedance)

Based on this data, Boeing recommends lowering the 747-8F maximum operating altitude limit by 1,000 ft from 43,100 ft to 42,100 ft to compensate for the descent

altitude exceedance in order to meet th e conditions set forth in Exemption No. 9943.

Compliance will be documented using interpolat ion of the above certif ication flight test data in combination with lowering the ma ximum operating altitude limit as mentioned above, to show that the airplane is capabl e of being at or under 25,000 ft in 3 minutes, while maintaining compliant capability of being at or under 40,000 ft in 1 minute.

Request Although Boeing believes that th e intent of the exemption is met and that no change is required to the exemption, if a change is requ ired then Boeing an expedited revision to the partial exemption using the information pr ovided in this letter in support of showing compliance to the reference (a) partial exemption, by reducing the maximum operating altitude of the Boeing 747- 8 Freighter from 43,100 ft to 42,100 ft based on the May 16, 2011 certification flight test data.