曝光台 注意防骗
网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者
(c) To ensure that no burrs remain after drilling, implementation of
supplier auditing, an additional cleaning process at the safety valve
manufacturer, and 100% inspection of key dimensions.
(d) Total inspection for stem poppet straightness (no bending).
(e) Implementation of control valve leakage test.
(f) Training of personnel in correct shim adjustment.
② Improvement of CMM
a. Designation of the stem assembly as a non-repairable part.
b. Revision of the CMM, reflecting to make the production process consistent
with the method of adjusting the operating point of the valve.
(2) Corrective Measures following this incident investigation
As a result of the additional safety valve investigations carried out in this serious
incident investigation, a revised CMM reflecting the following contents was issued
on March 13, 2002.
① Establishment of a minimum limit for adjustment screw protrusion.
② Execution of the Positive Relief Test at least three times to verify the set value.
Also establishment of its tolerances of the lower and upper limits.
③ Supplement paragraphs relating to troubleshooting tests with confirmation of
2 1
motion of the stem poppet and with leakage tests of the stem assembly and the
control valve.
5.2 Response of the Aircraft Manufacturer
The AMM was revised on May 1, 2002, such that a Relief Test of the safety valves is also
carried out three or more times with the valves installed in the aircraft.
5.3 Response of the ARS
(1) Based on an “Engineering Order” issued by the said company, the work sheet for
repair was revised to specify that the Relief Test be repeated at least three times to
verify no scatter of the calibrated value.
(2) The revised contents of the CMM as described in section 5.1 (2) were reflected to the work
sheet on June 12, 2002.
5.4 Response of the said Aircraft Operator
(1) Provisional Measures
Relief Tests were conducted on the safety valves installed on Airbus A320-200 and
A321-131 aircraft belonged to said aircraft operator.
(2) Permanent Measures
The stem assemblies of the safety valves installed in all Airbus A320-200 and
A321-131 aircraft belonging to the said aircraft operator were replaced with ones
manufactured on and after May 2001 and that incorporated the manufacturing
improvements, and at the same time, the shim thickness of a stem assembly was
verified and corrected as necessary.
22
Figure1 Three views
Unit：ｍ
11.8
33.9
37.6
-5000
0
5000
10000
15000
20000
25000
30000
35000
40000 11:20:00
11:22:00
11:24:00
11:26:00
11:28:00
11:30:00
11:32:00
11:34:00
11:36:00
11:38:00
11:40:00
11:42:00
11:44:00
11:46:00
11:48:00
11:50:00
11:52:00
11:54:00
11:56:00
11:58:00
12:00:00
12:02:00
12:04:00
12:06:00
12:08:00
12:10:00
12:12:00
-1
0
1
2
3
4
5
6
7
8
9
Figure 2 DFDR etc. data
Deff. Press.(psi)
Alt.(feet)
Deff. Press.
JST
Aircraft Alt.
Cabin Alt.
Detected Time of Safety Valves Open
23
24
Aft Pressure Bulkhead
Safety Valves
Figure 3 Installed Position of Safety Valves
Figure 4 Cross-Sectional View of Safety Valve
Servo Chamber ①Servo Chamber ②Cabin Chamber ③Gate ④Control Valve
⑤Setscrew ⑥Internal Bore ⑦Stem, Poppet ⑧Diaphragm
⑨Sensing Hole for Cabin Pressure ⑩Sensing Bore for Ambient Pressure
⑪Poppet Valve ⑫Airhole in Central Screw ⑬Air Filter
Ambient Pressure
Aft Pressure Bulkhead
Cabin pressure FWD
25
①Stem Asembly
②Seat Asembly
③Bushing
④Ｓeat
⑤Stem Poppet
⑥Stem Spring
⑦Stem Guide
⑧Shim
⑨Set Screw
⑩Diaphragm
⑪Spring
⑫Cover of Control Valve
Figure 5 Internal Structure of Safety Valve
- 2 6 -
Figure 6 Cross-Sectional View of Control Valve
The Whole of Control Valve
Shim
The length from the cover
to the tip of a adjusting
screw Stem Assembly
Cross-Sectional View of Stem Assembly
Stem Poppet
The contacting surface between
Stem Poppet and Seat Assembly
Stem Spring
Seat Assembly
Bush
Stem Guide
Cover, Sensor
Spring A Spring B
27
Figure 7 Description of photographed points
An arrow shows below the direction with fault observed under the microscope
inspection about each part.
Photo4
Photo5
Photo7 Photo6
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AIRCRAFT SERIOUS INCIDENT INVESTIGATION REPORT ALL NIPPON AI(10)
