Goodday,

I have been training in the 74 for a few weeks now with the help of a lot of KLM 747 manuals (FCOM's, MEL's etc), and i've noticed that the packs are Always in High Flow, and never in normal flow. This is what the FCOM says:

HIGH FLOW switch              FWD cargo airflow selection                      Pack flow during cruise                            Block fuel increment

                                                                                                                 #1           #2              #3

OFF                                      OFF                                                             NORM    NORM       NORM                     0,0%

                                             LOW                                                            NORM     HI             NORM                      0,3%

                                             HIGH                                                           HI             HI             NORM                      0,5%

ON                                        OFF                                                             HI             HI             HI                             0,8%

                                             LOW or HIGH                                               HI             HI            NORM                       0,5%

 

From what I understood is that whenever the high flow switch is off, only 2 packs are able to operate in high flow. So then, why do i have my packs running in high flow all the time on all packs with the switch turned off?

 

Cheers

How far into cruise are you checking the packs. All packs should be high until 30 min after reaching the programmed cruise altitude if I recall correctly.

Just now, thibodba57 said:

How far into cruise are you checking the packs. All packs should be high until 30 min after reaching the programmed cruise altitude if I recall correctly.

Just on the ground at the moment, but i've never on any flight seen it operate in normal flow anyway on any flight

Just now, Maurits Veen said:

Just on the ground at the moment, but i've never on any flight seen it operate in normal flow anyway on any flight

We'll check an hour into the flight and see what the packs are doing.  Ensure the LLCFR selector is off and the High Flow switch is off.  But all packs should be in High for climbout.

4 minutes ago, thibodba57 said:

We'll check an hour into the flight and see what the packs are doing.  Ensure the LLCFR selector is off and the High Flow switch is off.  But all packs should be in High for climbout.

llcfr?

Oops typo on my phone.  LLCCAFR Upper overhead panel FO side.  Allows temperatures to be selected for the Lower Lobes

Lower Lobe Cargo Conditioned Air Flow Rate selector.  

Position or this switch can put one, of all three packs in high during cruise inadvertently if selected incorrectly.

Just now, thibodba57 said:

Oops typo on my phone.  LLCCAFR Upper overhead panel FO side.  Allows temperatures to be selected for the Lower Lobes

Lower Lobe Cargo Conditioned Air Flow Rate selector.  

Position or this switch can put one, of all three packs in high during cruise inadvertently if selected incorrectly.

That's not installed on the KLM aircraft

9 minutes ago, Maurits Veen said:

That's not installed on the KLM aircraft

Might just be a freighter thing. I can't recall from our PAX aircraft honestly. Not something we ever deal with.  Then disregard that switch.  🙂

23 minutes ago, thibodba57 said:

How far into cruise are you checking the packs. All packs should be high until 30 min after reaching the programmed cruise altitude if I recall correctly. 

Should be faster than that. The packs should go into normal flow in "Cruise Clamp". This is defined by:

Above 25,000' and within 100 feet of cruise altitude.

The ECS miscellaneous card receives the climb, cruise, descent and
altitude information from the EIUs.

This data is passed on to the pack controllers and other controllers.

Not all packs should go into normal flow at the same time. There should be a 15 second delay between packs.

2 minutes ago, thibodba57 said:

Might just be a freighter thing. I can't recall from our PAX aircraft honestly. Not something we ever deal with.  Then disregard that switch.  🙂

Oh you fly the 744 irl? 😄 Would be strange if PMDG got this wrong but i don't remember ever seeing the ECS page without HI FLOW above them three. I'll take another look to be extra sure soon and then i'll come back to this post. 

Btw now i am talking to a 744 pilot anyway, do you know where the emergency/test switch is located for the oxygen test in preflight? Can't find it in the PMDG 

3 minutes ago, Maurits Veen said:

Oh you fly the 744 irl? 😄 Would be strange if PMDG got this wrong but i don't remember ever seeing the ECS page without HI FLOW above them three. I'll take another look to be extra sure soon and then i'll come back to this post. 

Btw now i am talking to a 744 pilot anyway, do you know where the emergency/test switch is located for the oxygen test in preflight? Can't find it in the PMDG 

Like the mask test?  You depress two buttons on the mask to get it to "test" audibly, the intercom on speaker and test to ensure the bottle is open by the status page.  I'm not sure of one on the Passenger aircraft. It's not to say there isn't one. Just not required by us to test it.  Might be a maintenance function.

1 hour ago, thibodba57 said:

Like the mask test?  You depress two buttons on the mask to get it to "test" audibly, the intercom on speaker and test to ensure the bottle is open by the status page.  I'm not sure of one on the Passenger aircraft. It's not to say there isn't one. Just not required by us to test it.  Might be a maintenance function.

I do a normal check like in the video (which i forgot to attach lol), but then the FCOM says this:

'Departing from AMS or after maintenance action on oxygen system:

RESET/TEST switch - Push and hold

EMERGENCY/TEST selector - Push and hold

While continuing to hold the RESET/TEST switch down, push the EMERGENCY/TEST selector for 10 seconds. Verify that the yellow cross appears continuously in the flow indicator.

Verify that the crew oxygen pressure does not decrease more than 100 psi.

If the oxygen cylinder valve is not in the full open position, pressure can:

• decrease rapidly, or

• decrease more than 100 psi, or

• increase slowly back to normal

Normal/100% selector - 100%

Crew and passenger/supernumerary oxygen pressure - Check

        Verify that the pressure is adequate for dispatch.'

Edited August 3, 20187 yr by Maurits Veen

 The switches are on the mask itself.  The status page shows the Oxygen pressure.

Just now, thibodba57 said:

 The switches are on the mask itself.  The status page shows the Oxygen pressure.

Only got a reset/test switch, does this mean the emergency/test selector isn't installed on the PMDG or does you airline not include this feature?

Maurits you absolutely don't need the oxy mask in the simulator and you only have one mouse cursor.... so as far as I know PMDG have simplified the oxygen test to the single button being pressed so that you hear the whizz sound.

Edited August 3, 20187 yr by Ephedrin