SR
# 3-4831788931 #
DESCRIPTION:
CEA can't find the installation torque of the brake hydraulic fuse(PN 2-8041-1) in normal and alternate brake system when do the ref/A/ and ref/B/ task.We can't identify the materials of fuse body.
Q1. Could Boeing provide the body material information of the PN 2-8041-1 fuse and the installation torque values?
Q2. CEA also needs the body material information of these PN fuses:
2-8020-29
2-8020-6
2-8020-25
2-8020-1
2-8020-27
2-8020-3
2-8020-5
2-7680-1
2-8020-28
RESPONSE:
A1. For part number 2-8041-1 (only):
(a)The material composition of the component includes:
i.Body: 15-5 PH CRES; and
ii.Plug/End Fitting: AMS 4640, AL-NI-BR (Aluminum Nickel Bronze).
(b)Boeing recommends an installation torque value of 270 in-lbs.
A2. The body (only) material information for the following fuse part numbers are:
(a)Aluminum: 2-8020-1, 2-8020-3, 2-8020-5 and 2-8020-6.
(b)Stainless Steel: 2-8020-25, 2-8020-27, 2-8020-28 and 2-8020-29.
To properly respond to China Eastern Airlines' question, as posed in BCS Message CEA-CEA-21-1609-01C, Boeing Engineering conducted additional research and testing on several hydraulic fuses composed of the Al-Ni-Br end fitting material.
Boeing Engineering research concluded that, per AMS 4640, the hardness value for Al-Ni-Br will typically exhibit hardness values much higher than aluminum alloys, but also exhibit hardness well below that of most 15?5 CRES heat treatments (please see below).
6061-T6 Aluminum: ~95 HB
AMS 4640 (Al-Ni-Br): 201-248 HB for material < 2"
Ti-3Al-2.5V Titanium:~290 HB
15-5 (CRES):>300 HB (depending upon HT level)
Thus, Al-Ni-Br alloy is closer to Ti or CRES, although not quite as hard as those materials.
Likewise, from additional sample pass testing at the CRES/Titanium torque value, for Fuse P/N 2-8041-1, Boeing Engineering recommends that, where the 3/8's Al-Ni-Br port connects to CRES or Titanium fittings and hose ends, to use torque value 270 in-lbs (+/-5%).
Note: Boeing is in the process of updating the applicable drawings and reference documentation to assist China Eastern Airlines and other airline Operators to determine installation torque values for hydraulic fuses composed of the Al-Ni-Br end fitting material.