Author Topic: FAQ (Frequently Asked Questions) and tips for DHC-8-402Q  (Read 30475 times)

Chris Liu

  • Management
  • *****
  • Posts: 993
    • Intercity Airways
Before requesting assistance for Dash 8 Q400 issues, please read the following FAQ carefully which address the following issues:

• Fuel planning and performance data calculations
• Aircraft yaws/rolls after takeoff
• Cannot set MCP (autopilot) altitude
• Cannot steer on the ground
• Cannot turn on TCAS
• VNAV issues
• Speed, power and flap settings, aircraft configuration
• Prop 1060 RPM and PEC failure
• Nose down trim upon autopilot disconnect
• Cannot retract landing gear
• Excessive turbulence effects
• Internal camera view "shakey"
• Miscellaneous

Pilots should familiarise themselves with the Standard Operating Procedure (SOP), both for the airline in general and those specific to the Bombardier Q400. We also highly recommend pilots complete the advanced/detailed tutorial from Majestic, which will enhance your understanding of the aircraft and teach you the essentials of managing the engines. There are also brief explanations of all the aircraft's main systems available here.

There is a web-based takeoff performance app (requires free registration) from Aurasim, available by clicking here and a V-speed cards
are at The additional triangular speed bugs, solid and hollow, are for Vfri and Vclimb, Vref and Vga, respectively

Plan trip fuel as 1100 kg per hour, plus holding 800kg/hr and taxi 100 kg. Fuel burn in cruise is typically 1100kg/hr (Vmo-10) or 950kg/hr (Vmo-20, 87% NL). Use Vmo-20 unless you're behind schedule or have strong headwinds.

Typically you will need trip fuel plus 1500 kg, remember you must land with at least 450 kg remaining or declare an emergency, so if you anticipate a long hold or nominate a distant alternate you should add extra fuel.

Even short Q400 hops should be able to reach FL210+ with relative ease, cruising in the teens really puts fuel consumption up and should be avoided. Generally there's precious little reason not to cruise at or near the service ceiling of FL240-250. There's a chart at



The left tendency is caused by yaw generated from the "prop wash" because both propellers rotated in the same direction. Counteract it using the rudder pedals and trim; set rudder trim right 1 needle width (about 14 units) before takeoff and you'll have a lot less to fight with once your airborne. You'll need to gradually reduce the trim as you accelerate, neutralising it when you're in the cruise.

You can disable it using the mjc84.ini file if it's annoying you, add the following line:
YAW_DUE_TO_PROPWASH=0 (instead of default 1.0)

Alternatively you can use autorudder to counteract the yaw moment. You need to enabled autorudder in your FSX/P3D settings and the following line in the MJC84.ini:
AUTO_RUDDER_FACTOR=0.8 (value is adjustable between 0 and 1)

Ensure your FSX is not set to Metric units

The rudder pedals only allow for +-8 degrees of nosewheel movement; if you set option 2 in the control manager you can use the aileron axis to control the tiller, providing nosewheel steering switch has been selected on (the switch is in front of the tiller). This provides for +-70 degrees of steering lock.

ON for takeoff only:
• AUTOFEATHER - If an engine fails its propeller is angled in to the lowest drag position
ON for takeoff and landing:

• STBY HYD PUMP - Electrically driven backup pump that will pressurise Hyd 1 system.
• PTU CTRL - Power Transfer Unit, allows Hyd 1 system to pressurise Hyd 2. Automatically activates if flaps are not selected 0 or engine 1 fails, but should still be manually turned on for takeoff and landing anyway.
• AUX PUMPS - will feed fuel to the engines if the primary ejector pump fails

VNAV can only be selected on the MCP 2 minutes before computed Top of Descent (ToD), when a magenta "v" is displayed on the PFD above the vertical deviation scale. Make sure that the MCP selected altitude is below the current level.

The FMS will not calculate a ToD unless altitude restrictions are entered for at least one waypoint, and these should not be entered until you are in the cruise (i.e. after ToC)

There is a full tutorial on VNAV descents available at:

Cannot turn on TCAS
• Ensure Audio and Radio Control Display Unit (ARCDU) is on, there is a knob just below the ARCDU screen, to the far left.
• Click and hold the LSK4R/8 (the button at the bottom right of the ARCDU display) for at least 2 seconds
• TCAS now should be activated, check for "ALT ON" in the bottom right of the ARCDU

Takeoff Flaps 5 and Reduced Torque Takeoff (RTOP) 81% and bleeds off on dry runways in excess of 2000m/6500ft length. Flaps 10 and NTOP and bleeds off for shorter or contaminated runways (this is Intercity SOP). Remember: STBY HYD PRESS, PTU CNTRL, TANK AUX PUMPs and AUTOFEATHER should all be enabled for takeoff.

After takeoff, pitch for V2+20 until acceleration altitude (1500 ft AGL) and then select MCL 900 rpm and accelerate to 185 knots, retracting the flaps on schedule. Passing FL100, accelerate to 210 kts (Bombardier Type I profile). Remember: Turn the engine bleeds on at acceleration altitude, and turn off standby hydraulics, PTU, aux pumps and autofeather.

Cruise Bombardier recommend using 850 rpm and MCR. Fly at Vmo-20 and fuel burn drops to around 900 kg/hr (roughly 87% NL), this is the normal profile at Intercity.

Vmo-10 for cruise and descent on a 3 degree FPA will give you a fuel burn of around 1000 kg/hr; use this profile if you are behind schedule.

If you have a good tail wind, you can also cruise at about 210kts indicated, Vmo-40, about 84%NL) and see less than 800 kg/hr.

The Q400 has strong climb performance and you should be able to reach at FL210+ on even the shortest of legs; avoid cruising in the teens as fuel burn goes up and TAS goes down a lot (i.e. if you cruise too low you will be late!)

Maintain speed at Vmo-10 in the descent, remembering to be at 250 KIAS for FL100 and then reduce to 245 KIAS for FL80 (windscreen limitation)

Approach and Landing
At >240 KTAS the FMS can skip waypoints which are close together and/or require sharp turns. Refer to charts for Vref speed. Remember: STBY HYD PRESS, PTU CNTRL, TANK AUX PUMPs should be enabled for landing, but not autofeather.

Suggested flap extension speeds:
0'/175.   5'/160    10'/150   15'/145

Land Flaps 15 unless LDA <1800m/6000ft or steep approach, then use Flap 35. The aircraft is a lot harder to handle at Flaps 35 and much more sensitive to power changes. If landing Flaps 35, do not cut power during the flare as this causes rapid decay of airspeed and subsequent heavy touchdown, because of a reduction in propeller wash over the wing.

If you are suffering from continual heavy landings, a comprehensive advice from a Q400 type rated pilot is available at

Prop 1060 RPM and PEC failure
If you accidentally move the condition levers in to feather (which is very easy when using the mouse, sometimes they can jump straight from max to feather) it will often cause PEC failure and 1060 rpm prop overspeed. The quick fix is to pop the condition levers to shut off, then quickly move them back to full before the engine shuts down which usually resets the PECs and gives propeller RPM control back - this is slightly Russian roulettey as you might accidentally turn the engines off altogether! In reality the QRH states you have to divert and sort the problem on the ground.
Slowly tap CTRL SHIFT F2 to adjust the condition levers and they're less likely jump. Also ensure the ranges set in the Majestic control panel help avoid accidentally going in to feather. It you're using an external controller for prop RPM it could be "spiking" or improperly calibrated causing this behaviour.


Add AFCS_FSX_SYNC=0 to the MJC84.ini and then add autopilot_available=0 to the aircraft.cfg for the Q400. This will completely disable the default FS AP and prevent it conflicting with Majestic's. Also check that you have no conflicting control mappings, particularly if you use the optional 125 Hz control input.


This is normally caused by Dynamic Head Movement (DHM) feature of EzDok. Turn the DHM setting down to almost zero, you may also need to adjust the inertia/G-force movement.


This is usually caused by the gear locking pins not being stowed on PRO edition, their insertion upon aircraft initialisation is random so you must check prior to engine start. You will see red "remove before flight" tags hanging out the bag behind the first officer's seat if the pins are stowed. If you can't see the tags, you need to click on the bag or use the FMS to stow them, note they can only be stowed whilst on the ground with engines off and door 1L open - if you see "GROUND OPS ONLY" on the FMS it means you are not complying with this requirement. In reality the pins are used to prevent the landing gear collapsing when the aircraft is powered down on the ground, obviously the door must be open so they can be bought in to the aircraft!


You can adjust the turbulence susceptibility in the MJC84.ini using a scalar under the [FLIGHTCONTROLS] section:

I suggest .45 if you're using ASN or experience exaggerated turbulence effects. Default .75, Min 0.0, Max 1.0. The general consensus is that 1 results in unrealistically harsh turbulence.

You can disable cabin announcements in the mjc84.ini file (end of file). You can also disable them for once through the FMS.

You can adjust the likelihood of wear based failures in the mjc84.ini:
Setting 0 will disable them, setting 10 will make them 10 times more likely than reality.
Failures and damage will reset after the aircraft has been on the ground with engines off for 20 minutes.

Other mjc84.ini lines you may find helpful:
« Last Edit: Thu 08 Nov 2018, 16:03 by Chris Liu »