Pressurization System

[louross]

Everytime I fly the 9 (DC9-30) the red pressurizaton warning light is on the annunciator panel. Can't figure out what I've set up wrong.
Today, flew the AeroCalifornia for the first time, and on approach when I set flaps at 20 (I think), a warning horn came on and remained until I shut down FS. Power up didn't help, gear down didn't help, nor increased flap settings. Maybe it was just one of those things on this one flight. But, any ideas???
Next time, I'll try to take a screen shot of the overhead panel.
lr.

[ross]

Hi ....without much to go on, here's a quick guess/suggestion.....to silence the gear warning, click on the white button immediately to the right of the orange master warning light on the glareshield......for the pressurization...are you closing the outflow valve by moving it to auto ?...that's the yellow thing between the thrust levers and the flaps lever....

Cheers
Ross

[louross]

Yep, maybe it was not closing the outflow valve. I'll check that on the next flight. My fault I missed the warning silencer. Thanks!
lr.

[aerofoto - HJG Admin]

"NO" .... it´s not the Gear Warning Horn that you´re hearing.

What you´re hearing is the Cabin Pressurization Warning Horn .... telling you that the cabin is not pressurizing.

What you´ve failed to do here is to dial-up a cabin pressure altitude value on the CABIN ALT SET selector dial associated with the "CABIN PRESSURE CONTROL" section of the Overhead Panel .... and then additionally .... you´ve also forgotten to set the yellow Cabin Pressurization system tab (located on the Center Pedestal panel .... above the CP Rudder trim knob) to the "CABIN ALT" position .... and which will all in-turn trigger a warning horn as well as an red iluminated "PRESSURIZATION" warning lamp on the Overhead Panel annunciator panel when passing through approximately 10,000 FT.

If I´m intending to cruise at FL310 .... I set the CABIN ALT SET value to read about 8,500 FT usually prior to taxiing .... then .... as I commence my T/O roll I next set the Cabin Pressurization system tab to the "CABIN ALT" position. Perform both of these procedures .... and you´ll be fine.

REMEMBER .... setting a cabin air pressure value .... and then actually getting the cabin air pressurization system to function is a fully manual 2-part action ....as related above.

These details are covered more fully in both SECTION 2.1 and 2.3 (both sections relate to the Overhead Panel) .... and both SECTION 4.0 and 4.4 (both sections relate to the CEnter Pedestal Panel) of my online/forum based DC9 manual .... "DC9 PANEL INSTALLATION & HANDLING NOTES" .... located at the top of this particular forum page. These notes should be considered essential reading for everyone new to the HJG/HILMERBY DC9 panels. These panels can´t be flown properly if people try to "wing it". These notes go much further than just explaining Panel Installation alone .... and go on to explain almost everything that is essential to be known in order to get the very best enjoyment/performance out of these panels and aircraft.

For your quick reference here are the appropriate manual sections ....

2.1: OVERHEAD PANEL.



Starting at the top left quadrant of the Overhead Panel and working down ....

This section of the OH Panel features the Electrical system .... labeled "ELEC PWR"

Both "L GEN, R GEN", and "DC BUS VOLT" switches are of paramount importance in this section. Failure to set these switches correctly will result in a compete electrical systems failure which will render both the AP and Radios inoperable .... along with all other electrically dependent panel instrumentation !

The bottom left quadrant of the OH Panel features both the Engine Startup switches and Cabin Signs switches .... labeled "ENG" and "CABIN SIGNS" respectively

Moving down towards the bottom center left quadrant of the OH Panel and then working up ....

This section of the OH Panel features both the Anti-Ice system switches, and Fuel Pump switches .... labeled "ICE PROTECT" and "FUEL PUMPS" respectively.

The Fuel Pump switches are of paramount importance in this section. All of these must be selected "ON" prior to engine startup or the engines will not start.

Located at the center left of the OH Panel is the APU System .... labeled "APU".

Moving up towards the top right quadrant of the OH Panel and then working down ....

This section of the OH Panel features the Logo Light switch, Emergency Lights Arm switch, Coockpit Floodlights switch, and CVR system buttons.

Located along the center right of the OH Panel is the Position Strobe Lights switch, Anti-Collision Lights switch, Cabin Attendant Call button, external PA Coms button, Anti-Skid switch, and Yaw Damper Switch, and SPD CMD TEST" switch.

Selecting the OH Panel "POS/STROBE LTS" and "ANTI COLLISION" lights switches "ON" also activates these same lighting switches on the Main Panel. FOR FURTHER INFORMATION REFER TO SECTION 1.13.

Moving down towards the bottom center right quadrant of the OH Panel ....

This section of the OH Panel .... labeled "AIR CONDITIONING" .... features the Air Conditioning System, Radio Rack Ventury Fan switch, Air Conditioning Auto Shut-Off switch, Ram Air switch, and the Cabin Pressurization control System. FOR FURTHER INFORMATION REFER TO SECTION 2.3.

Both the Air Conditioning "SUPPLY" switches and Cabin Pressurization selector knob are of paramount importance in this section. These must be selected "OFF" during engine startup sequences or the engines will not start.

The Cabin Pressurization scale must be set, and the CP Cabin Pressurization system lever also set, in order for the cabin to be able to pressurize and to avoid a pressurization failure warning when passing through 10,000 FT.

Moving down to the very bottom quadrant of the OH Panel and the back towards the center left ....

This entire section of the OH Panel features the Annunciator warning lamp system, and the Windshield Wiper control knob in a section labeled "RAIN".


2.3: OVERHEAD PANEL - CABIN PRESSURIZATION SYSTEM

The "ALTITUDE" knob located on the "CABIN PRESSURE CONTROL" section of the Overhead Panel must be set to the desired cabin altitude pressure value for high altitude cruise. Clicking this knob sets the cabin altitude pressure value. Mousing the right side of the "ALTITUDE" knob raises the altitude value displayed in the vertical "ALT/CABIN ALT SET" scale. Mousing the left side of the "ALTITUDE" knob reduces the altitude value displayed in the vertical "ALT/CABIN ALT SET" scale. FOR FURTHER INFORMATION REFER TO SECTION 2.1.

The Numerals displayed in the left "CABIN ALT SET" scale gauge window refer to altitude values in units of 1,000 FT.

The numerals displayed in the right side of the right "CABIN ALT SET" scale gauge window refer to altitude/barometric air pressure values in millibar units.

Clicking the "BAR CONT" knob (located above the "ALTITUDE" knob) adjusts the altitude barometric air pressure value. Mousing the right side of the "BAR CONT" knob raises the altitude barometric air pressure value displayed in the gauge window/scale. Mousing the left side of the "BAR CONT" knob reduces altitude barometric air pressure value displayed in the gauge window/scale.

Immediately prior to T/O the yellow Cabin Pressurization system tab (located on the Center Pedestal panel .... above the CP Rudder trim knob) must also be set to the "CABIN ALT" position. Failure to do this will result in the aircraft cabin not being able to pressurize during climb to altitude .... FOR FURTHER INFORMATION REFER TO SECTION 4.4. This will trigger a pressurization failure alarm when passing through 10,000 FT .... resulting in the illumination of both the red "MASTER WARNING" lamp on the Main panel as well as the "CABIN PRESSURE" warning lamp on OH Annunciator Panel.


4.0: CENTER PEDESTAL PANEL



Starting from the left quadrant and moving across towards the right and then down the Center Pedestal sub panel ....

The entire upper section of the CP sub panel features the Trim indicator, Speedbrake/Spoiler lever, Rudder Hydraulics power lever, Auto-throttle system lever, Engine #1 and Engine # 2 thrust levers, Engine #1 and Engine #2 Startup fuel levers, fuel crossfeed lever, Cabin Pressurization system lever, and the Flap lever.

Moving down towards the bottom right quadrant the CP sub panel ....

Located at the center bottom right of the CP sub panel is the Rudder Trim knob, and both Engine #2 and Engine #2 pnuematic fuel Valve crossfeed levers.


4.4: CENTER PEDESTAL PANEL - CABIN PRESSURIZATION SYSTEM LEVER

The CP Cabin Pressurization system lever is the small yellow tab located above the CP Rudder trim knob. This tab must be set to the "CABIN ALT" position prior to T/O or the aircraft cabin will not pressurize. FOR FURTHER INFORMATION REFER TO SECTION 2.3.

Again .... I urge people to read the full manual !

Mark C
BOG/COL

[ross]

Hmm ....did I misread this part.."and on approach when I set flaps at 20 (I think), a warning horn came on and remained until I shut down"

Ross

[aerofoto - HJG Admin]

and on approach when I set flaps at 20 (I think), a warning horn came on and remained until I shut down

The landing gear should be extended from FLAP 15 (or thereabouts) and before going to FLAP 20. If FLAP 20 is selected .... and the gear is not alreadyextended .... then this will trigger the Gear WArning Horn to activate.

I have covered this also .... in SECTION 1.13 of my online/forum manual .... "DC9 PANELS INSTALLLATION & HANDLING NOTES".

Quick reference as follows ....

1.13: MAIN PANEL GEAR WARNING HORN CANCELATION BUTTON

The landing gear warning horn cancellation button (a very small grey button) is located at the left of the pair of wing landing light switches. This button is labelled "GEAR HORN OFF".

It has been observed that (for reasons yet to be determined) the landing gear warning horn may, on rare occasions, be triggered automatically .... a long continuous tone. Clicking the "GEAR HORN OFF" button will cancel this warning horn should it ever be triggered.

Under normal circumstances the landing gear warning horn will only be triggered when the flaps are extended beyond 15* and before the landing gear has been extended. In this case it is not possible to cancel the landing gear warning horn using the GEAR HORN OFF button. In this case this warning horn will be cancelled, automatically, only when the landing gear has been fully extended.

On some systems (only) it has been noted that the Gear Warning Horn may be activate at unusual times .... or .... once activated it may not disactivate automatically when the gear is finally extended.

In such cases .... clicking the "GEAR HORN OFF" button on the Main Panel (as prescrbed in the above manual extract) will cancel the horn.

Mark C
Mark