1、MIL-T-8207B (USAE) 18 June 1973 SUPERSEDING MIL-T-8207A(USAF) 28 February 1955 MILITARY SPECIFICATION TEST PROCEDURES FOR AIRCRAFT AND ENCLOSED ESCAPE SYSTEM PRESSURIZED COMPARTMENTS 1. SCOPE 1.1 This specification covers the standard methods for testing pressurized compartments by flight and ground
2、 tests of pressurized aircraft and enclosed escape systems, including pressure suits. 2. APPLICABLE DOCUMENTS 2.1 The following documents, of the issue in effect on date of invitation for bids or request for proposal, form a part of this specification to the extent specified herein: SPECIFICATIONS M
3、ilitary MIL-T-5337 Test.er, Pressurized Cabin Leakage, Aircraft, Type MB-1 MIL-T-26139 Tester, Pressurized Cabin Leakage, Aircraft AF/M24T-3 MIL-T-26140 Tester, Pressurized Cabin Leakage, Aircraft AF/M24T-2 MIL-T-26141 Tester, Pressurized Cabin Leakage, Aircraft AF/M32T-1 PUBLICATION Air Force Syste
4、ms Command Design Handbook DH 2-8 Life Support (Copies of specifications, standards, drawings, and publications required by suppliers in connection with specific procurement functions should be obtained from the procuring activity or as directed by the contracting officer.) 3. EQUIPMENT 3.1 Speciali
5、zed tests. Specialized tests for pressurized aircraft compart- ments fall into. three categories as follows: a. Structural testing of static test articles (to be performed only when required by contract) FSC 15GP A Provided by IHSNot for ResaleNo reproduction or networking permitted without license
6、from IHS-,-,-IL-T-82078 35 m 7997706 0386463 9 m MIL-T-8207B (USAF) b. Ground testing of flight articles c. Flight testing of flight articles. 3.2 Equipment approval. The equipment used in the testing of aircraft pressurized compartments and enclosed escape systems shall be subject to the approval o
7、f the procuring activity. A description of the equipment shall be included in the test report (see 4.5). 4. TEST PROGRAM 4.1 Procedures and methods. Procedures and methods used that are not specified herein shall be described in detail and data provided that will facilitate comparison with standard
8、procedures. Procedures and methods differing from those described herein shall be approved by the procuring activity prior to actual testing. 4.2 Structural testing of static test article 4.2.1 Static tests. The pressurized compartment structure shall be static tested as specified by the procuring a
9、ctivity. Tests are required to either the limit (or design yield) load, design ultimate (or failing) load for critical conditions of maneuver, or gust flight loads and differential pressure loads acting alone and in combination, including the effect of sudden disintegration of canopies such as from
10、gunfire, improper installation, or any other cause. I 4.3 Ground testing of flight article 4.3.1 Test equipment 4.3.1.1 Pressure source equipment. The equipment used as a pressure source in ground pressure testing of aircraft pressurized compartments shall depend upon the permissible design leakage
11、of-the aircraft which is a function of the volume and configuration of the pressurized compartment and test pressure differential. The proper testers for given ranges of design leakage and pressure differentials shall be as specified in table I. 4.3.1.2 Equipment for determining leak locations. Stan
12、dard smoke generators, stethoscopes, ultrasonic sound pressure detectors, or soap solution may be used during the course of a pressure test to determine the locations of leaks that require repair in order to.meet the leakage requirements. I 4.3.2 Frequency of tests. Under the following circumstances
13、, ground pressure I requirements. tests shall be conducted to.determine compliance with design leakage Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-T-AWB 15 m vwm IIALL II m MIL-T-8207B (USAF) TABLE I. Tester Ranges 2-12.5 2-12.5 2-12.5 2-12.5
14、 Capacity (cfm) Free Air L/ 10-200 10-400 10-400 10-200 I r Specification MB-1 MIL-T-5337 AF/M24T-3 MIL-T-26139 AF/M32T-1 MIL-T-26141 MIL-T-26140 Method of Operation Gasoline engine Electric motor Gasoline engine Electric motor - 1/ Cubic feet per minute (cfm) standard air (0.075 pound per cubic foo
15、t at 59.9OF). - 2/ Two testers of the same type may be manifolded together in the event a greater capacity is required and only one size of the tester is avail- able. Joining of the pressure and static lines should be as close to. the compartment fitting as possible. If required, commercial standard
16、 testers of greater capacity are available. 4.3.2.1 Functional configuration audit. Satisfactory compliance with permissible design leakage at maximum normal pressure differential shall be demonstrated either by data from previous test or by test performed during the functional configuration audit.
17、Data substantiating the basis for the amount of permissible design leakage shall be approved by the procuring activity prior to the configuration audit. 4.3.2.2 Production aircraft. Each pressurized production aircraft and enclosed escape system shall meet the design leakage requirements prior to ac
18、ceptance. 4.3.2.3 Service aircraft. Pressurized aircraft and enclosed escape systems in service shall be tested to determine compliance with the design leakage requirements at each major inspection, when the aircraft is unable to maintain 3 Provided by IHSNot for ResaleNo reproduction or networking
19、permitted without license from IHS-,-,-MIL-T-8207B (USAF) a minimum normal pressure differential in flight, and before the aircraft is released for flight after repair or rework (major or minor) to the pressurized compartment(s) or pressurizing and depressurizing equipment. 4.3.3 Temperature require
20、ments. Ground pressure tests shall be required at the existing ambient temperature only, provided the sealing system in the article, including flexible material seal installations, emergency relief vflve(s), and seam-sealing configurations, functions properly at both -65 and +160F. Test reports (see
21、 4.5) substantiating such ability sha1.l be provided the procuring activity prior to the first flight of the first aircraft of every production contract involving pressurized aircraft. 4.3.4 Test procedures 4.3.4.1 Attachment of ground test equipment. The ground pressure tester(s) shall be attached
22、to the fittings provided on the article. Except for the compartment pressure emergency relief valve, pressure outlets vented to outside air (such as the cabin pressure regulator and instruments) shall be closed off during the test. 4.3.4.2 Actuation of test equipment. The tester shall be started and
23、 pressure vented to the compartment and, if used, to the inflatable seal. 4.3.4.3 Quantitative determination of air supplied. When the tester cabin pressure gage indicates a design pressure differential, the amount of air supplied to the compartment shall be determined by reading the dial on the tes
24、ter flowmeter. 4.3.4.4 Determination of satisfactory sealing provisions. If the air supplied to the compartment (when the latter is pressurized to maximum normal pressure differential) is less than the design leakage, the compartment shall be considered properly sealed. 4.3.4.5 Determination of unsa
25、tisfactory sealing provisions. If the air supplied to the compartment (when the latter is pressurized to maximum normal pressure differential) exceeds the design leakage, the compartment sealing shall be considered inadequate. The inflatable seal shall be checked by the means available on the tester
26、. The tester shall be turned off, except for supply to inflatable seal, and the points of excessive leakage determined by one of the following methods: 4.3.4.5.1 Smoke generator method. Actuate a smoke generator inside the compartment and repressurize. Smoke will be observed at the points of excessi
27、ve leakage. 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-T-8207B L5 m 7797706 OLBb4bb 4 MIL-T-8207B (USAF) 4.3.4.5.2 Soap solution method. Apply soap solution at points of suspected leakage. Excessive leakage will be indicated by a high freq
28、uency of bubble formation at the leakage point when the compartment is repressurized. 4.3.4.5.3 Stethoscope method. Where leakage is difficult to determine, high leakage at seams or joints may be detected by differences in sound frequency heard-through a stethoscope applied to the seam or joint when
29、 the compartment is repressurized. 4.3.4.5.4 Ultrasonic sound pressure detector. Where leakage points are difficult to locate, leakage at seams or joints may be located by detecting ultrasonic sound pressure levels created by the flow of gas as it escapes from pressurized compartments. 4.3.4.6 Repai
30、rs during ground pressure tests 4.3.4.6.1 Rubber seals. Unless the seal is improperly attached to the structure, excessive leakage around rubber seal joints generally is an indication that the seal should be replaced. 4.3.4.6.2 Sealed seams. Excessive leakage at sealed seams in the metal structure s
31、hall be repaired by stripping the sealing compound at the leak, thoroughly cleaning the metal surfaces, and then resealing the seam. 4.3.4.6.3 Compartment pressure regulator and safety valve(s). Normal leakage around valves is to be expected and will be of the order of 0.5 pound v per minute for eac
32、h valve. If excessive leakage appears to prevail, the valve diaphragm(s) shall be visually inspected for rupture. The valve(s) shall be replaced if the diaphragm(s) is ruptured. The valve mounting seals also shall be checked. 4.4 Flight testing of flight article 4.4.1 Structural. Normal structural f
33、light demonstrations shall be made with the compartment pressurized at the normal differential. 4.4.2 Aircraft compartments 4.4.2.1 Flight tests shall be performed with the lowest possible rpm and with military power at a selected altitude between sea level and 10,000 feet, and.at each of the follow
34、ing altitudes: 10,000, 25,000, 35,000 feet, and service ceiling. 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-I MIL-T-8207B (USAF) 4.4.2.2 At each of the above specified altitudes, the aircraft shall be flown under level flight conditions until
35、flight conditions are stabilized (not less than 5 minutes). When conditions are stabilized, recordings shall be made of compartment and flight altitudes, rate of compartment pressure change, and mass flow of air to the compartment. Data shall be recorded with temperature controls in the full hot pos
36、ition and repeated with the temperature control in the full cold position. If adjustable or selectable pressure differentials are provided, proper operation of these controls shall be demonstrated. 4.4.2.3 The aircraft shall be operated in a normal rated power climb from sea level to service ceiling
37、 of the aircraft. The rate of climb of both the compartment and aircraft shall be observed and recorded at 5,000-foot aItitude increments or 2 minutes, whichever occurs more frequently. In addition, the maximum pressure change and maximum rate of pressure change shall be observed and recorded when t
38、he following transitional conditions occur: I a. Unpressurized compartment to a pressurized compartment and the reverse b. Constant compartment pressure altititde to normal differential pressure control and the reverse c. Normal differential pressure control to pressure ratio control or the reverse
39、if a pressure ratio control is provided Also, the rate of climb of compartment pressure shall be measured at some constant aircraft altitude (above that which gives isobaric compartment pressure) when the pressure schedule is changed from normal to combat, if applicable, and when the procedure is re
40、versed. 4.4.2.4 Tests shall be conducted at the maximum normal rate of descent of the aircraft to observe changes in compartment pressure altitude and com- partment pressure rate of change at increment altitudes and during transition periods as specified in 4.4.2.3, 4.4.2.5 At approximately 35,000 f
41、eet, the emergency compartment pressure release shall be operated and the time required for reducing the cornpartnent pressure from limit compartment differential pressure to the stabilized pressure that occurs with the emergency compartment pressure release in the wide-open position shall be determ
42、ined and recorded. The force and time required to open the various exits shall be measured and recorded. Repres- surization shall be initiated and the time required to fully repressurize the compartment shall be recorded. 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without
43、 license from IHS-,-,-MIL-T-8207B (USAF) 4.4.2.6 If the aircraft is divided into compartments which can be pressurized and depressurized separately, then: a. The equipment for doing this shall be tested at several altitudes, and b. The satisfactory behavior of other equipment which may be affected s
44、hall be verified. 4.4.2.7 These tests may be conducted concurrently with air conditioning tests. To insure compatibility of these tests with air conditioning tests, minor modifications in test procedures may be considered. However, any variation in test procedures shall be approved by the procuring
45、activity prior to testing. 4.4.2.8 Frequency of tests 4.4.2.8.1 Category I flight test aircraft. All of the above flight tests shall be conducted during the category I flight tests. 4.4.2.8.2 Production aircraft. Each pressurized production aircraft shall danonstrate satisfactory performance with th
46、e test requirements of 4.4.2.2 (35,000 feet and service ceiling only), 4.4.2.3, 4.4.2.4, and 4.4i2.6, if applicable, prior to acceptance by the using command. Standard instrumen- tation of the aircraft is considered adequate for these tests, 4.4.2.8.3 Service aircraft. Pressurized aircraft in servic
47、e shall be tested to demonstrate compliance with the appropriate test requirements of 4.4.2.2. (35,000 feet and service ceiling only), 4.4.2.3, 4.4.2.4, 4.4.2.5, and 4.4.2.6 after each major rework or repair to the pressurized compartment or pressurization system controls. The standard instrumentati
48、on contained in the aircraft is considered adequate for these tests. 4.4.3 Enclosed escape systems 4.4.3.1 Flight tests. Flight tests shall be performed at aircraft service altitude and at speeds that result in maximum Q-forces on the escape system. 4.4.3.1.1 The enclosed escape system shall be test
49、ed to determine the adequacy of the emergency pressurization subsystem to maintain the required pressure schedule. Vhere applicable, the above test should be accomplished during an actual dummy or animal ejection. Test procedures shall be approved prior to actual flight tests. 7 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4.4.3.1.2 The enclosed escape system shall be flight tested from
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