US Airways 2007 Annual Report Download - page 1126

7.4 The engines will be operated using not more than the engine manufacturer's maximum recommended outputs for take-off, maximum go-round,
maximum continuous, maximum climb and cruise for normal operation unless otherwise stated.
7.5 Where applicable the Guarantees assume the use of an approved fuel having a density of 6.7 lb per US gallon and a lower heating value of 18,590 BTU
per lb.
7.6 Speech Interference Level (SIL) is defined as the arithmetic average of the sound pressure levels in the 1000, 2000 and 4000 Hz octave bands. A-
Weighted sound pressure level (dB(A)) is as defined in the American National Standard Specification ANSI.4-1971.
7.7 All guaranteed interior noise levels refer to an A350-900 XWB Aircraft with standard acoustic insulation and an interior completely furnished. The
effect of Buyer furnished equipment other than leather passenger seats (leather seats or acoustically equivalent) will be the responsibility of the Buyer
(Remark: Standard seats tend to decrease interior noise levels by 1-2 dB)
7.8 For purposes of the sound levels guaranteed in Clause 5.2.1.2 of this Letter Agreement, the APU and air conditioning system will be operating. Sound
level measurements may be made at the prevailing ambient temperature with the air conditioning packs controlled to approximate air conditioning
machinery rotational speed appropriate to an ambient temperature of 25C.
8 GUARANTEE COMPLIANCE
8.1 Compliance with the Guarantees will be demonstrated using operating procedures and limitations in accordance with those defined by the certifying
Airworthiness Authority and by the Seller unless otherwise stated.
8.2 Compliance with the take-off, second segment, en-route one engine inoperative, approach climb and landing elements of the Guarantees will be
demonstrated with reference to the approved Flight Manual.
8.3 Compliance with those parts of the Guarantees defined in paragraph 2 and 3 above not covered by the requirements of the certifying Airworthiness
Authority will be demonstrated by calculation based on data obtained during flight tests conducted on one (or more, at the Seller's discretion) aircraft of
the same aerodynamic configuration as the Aircraft and incorporated in the In-Flight Performance Program and data bases ("the IFP") appropriate to the
Aircraft.
8.4 Compliance with the Structure Usable Load guarantee defined in Paragraph 4 will be demonstrated with reference to a weight compliance report.
8.5 The approved A350-900 XWB Aircraft flight manual will be used to demonstrate compliance with the guarantees of certification noise levels.
** Confidential Treatment Requested.
USA — Amended and Restated Airbus A350 XWB Purchase Agreement LA 8-2.A — 19 of 23
EXECUTION PRIVILEGED AND CONFIDENTIAL