B737 Isolation valve AUTO position

[Zenj]

AT

Thanks

Zenj

[junior_man]

I think the "why" you are looking for is this:
The 737 was designed a long time ago. To get rid of the FE some things had to be "automated". When you get a bleed or pack trip, you do not have to change any switch positions. If you go up and start moving switches, then they are assuming you are intending to do something, like wing anti ice.
Next Gen is designed to be flown as a common fleet with the old ones. That is why some of the things that could have been improved were not.

BTW there is a 727 hiding inside most Boeings. Just automated in some.

[Zenj]

Alaskan Timber

I do not see this info at all in FCOM Vol 1 SP16

Zenj

======

Hey Zenj,

FCOM (AOM) volume 1 suppl. procedures page 16.9.

rgds,

AT

[Popolama]

==
Above fl 350 wing anti-ice could also cause a bleed trip off with both bleeds working.
==

I have seen this info elsewhere twice and it was also stated that you can even lose pressurization of the aircraft , when this happens, now where is this source stated officially by Boeing ?

Zenj

QRH BLEED TRIP OFF June 6,2003
"CAUTION : Use of wing anti-ice above approx FL350 may cause bleed trip off and possible loss of cabin pressure.

hope that helps...

[Alaskan Timber]

Hej Zenj,

Both my FCOM (AOM) vol. 1 for the 700 and 500 mention this on page SP 16.9. Also in the QRH as mentioned by Popolama.

A.T.

[Zenj]

Popolama and AT

It's not that I disagree with you about this but I need it mentioned in the Boeing documents so that I can show to my other fellow crewman.

I have the QRH for B737-200 from old Air Tanzania on NON-NORMAL CHECKLIST section page NNC2.3 BLEED TRIP OFF dated 5th October 2001

and I have

QRH from B737-200 from new Air Tanzania ( same with SAA) same checklist but with date of April 4th 2003

Both they do not mention the FL350 and icing with bleed tripping

Same with FCOM page 16.9

If possible please scan it and send it to my e-mail

Thanks

Zenj