View Full Version : Q400 performance/fuel saving.

6th Jun 2007, 10:11
I fly the Q400 for a small regional airline ”somewhere in Europe”. I have the distinct feeling that we do not fully take advantage of the Q400’s potential. Here’s why:
- For take-offs, which are all on relatively long runways (shortest is EGPD/ABZ), we always use MTOP (90% TQ), no matter what our take-off mass is.
- We always use MCP, regardless of wind/velocity.
- We [almost] always pretend to be a KC-135, and haul around tons of extra fuel, even in severe CAVOK on short sectors.
- Climb/cruise/descend schedules are never “planned”; most pilots just pick a pitch/IAS randomly (or so it seems)
Are there any Q400 drivers out there who care to shed some light on how this aircraft is operated by other companies? Do you use reduced torque for take-off, as this would save fuel and reduce engine wear? Do you decrease cruising speed in a strong tailwind, in order to save fuel? (I’ve read that by reducing cruise speed by 60kt (from max), you can save 200kgs of fuel on a 1-hour flight!). Are you encouraged to use a low flap setting on approach to save fuel?
PM me if you feel like it! ;-)

Maude Charlee
6th Jun 2007, 17:04
Q400 driver at Europe's 'largest' regional airline.

Normal ops would be reduced power T/O on all flights except first of the day, where we use NTOP, with power 'flexed' to 81% on most runways except for the most limiting.

Cruise is usually at MCR settings, and SOP is to fly at Vmo - 10kts, though in practice most crews fly it closer to the speed tape red line. However, there are guys who will use long range cruise settings if timings mean an early arrival, and this brings fuel burn in the cruise down to around 850kgs per hour.

Tanking is encouraged where fuel is significantly cheaper (a differential of just 2% in the price is seen as significant), and a 'normal' excess above minimum fuel required is around 400-500kgs, depending on the crew and the expected wx situation.

Company SOP is a flap 35 landing, but again there is a mixture of flap 15 and flap 35 approaches in practice, depending upon pilot preference and runway length. I believe the SOP for flap 35 only came about as a result of a tail strike with a new pilot landing at flap 15 some years ago, but I may be wrong.

Pontius's Copilot
7th Jun 2007, 19:32
Same Co. as MC (I guess):

NTOP (which is presumeably what you mean rather than MTOP) gives a more fuel efficient take-off than flex power. But Co. policy may be determined by your engine leasing contract.

Not sure what you mean by MCP ... MCL for the climb? The difference between 850/MCL (using MCL discrete button) and 900 (which gives you MCL) is relatively insignificant, but we use 850/MCL primarily because the cabin noise suppression system (NVS) is 'tuned' at 850Np.
As MC says this aircraft will burn 2% of all extra fuel you take off with, unnecessary tanking simply wastes fuel by burning some just to carry some.

Your Operational Flight Plans must be prepared using a published profile of some sort - we use the Bombardier recommended "Type I climb/MCR (Vmo-10) cruise/Vmo-10 descent on 3degree FPA". We have the IAS versus Pitch argument - IAS is the only mode mentioned by Bombardier in the AOM, Pitch mode is a hangover from the Dash 8-300, in Pitch you cannot adjust rate of climb without changing speed, in IAS rate of climb is adjusted by power changes (no risk of losing ALT SEL), etc etc.
In any enroute wind condition, get up to FL150/FL180 asap (210kt) for best TAS and better fuel flow - then decide to go higher or stay there, depends on Mass, ISA Dev, Head/Tailwind, VMC/IMC (icing), Early/Late on schedule.

Once in the cruise review the ETA (in FMS), if early consider reducing speed to give ETA closer to STA. Your figure is probably close at LRC, we can easily save 10% of Trip on a 1h15 sector by flying about 210kt IAS, for a flight time difference of less than 10minutes

Again we 'discuss' the Flap 15/Flap 35 issue regularly, for us Flap 35 is mandatory on LDAs 1800m or less. The Ops Manual says Flap 35 is recommended, but the spoken/unwritten preference is for Flap 15 when possible. Flap 15 with RDC NP is prefection (in a turboprop): it is smoother, quieter, uses less fuel, saves flight time, reduces runway occupancy time, simplifies the go around and the engine failure on approach, and gives you the landing attitude (just reduce the sink rate at 20ft)

7th Jun 2007, 20:28
By MCP I meant MCL/MCR. We never use the reduced TQ option.

Great inputs; I'm trying to convince the chief pilot that we could save fuel and engine wear by using flex power, and reducing cruise speed if flying in a strong tailwind.


Piltdown Man
7th Jun 2007, 23:19
But is fuel your biggest expense? You will probably find that anything you can save in fuel costs will be lost on en-route charges, engineering, crewing and utilisation overheads. Fuel is a significant proportion of your overall costs but I bet that if you (tree huggers, please look away) flew flat out everywhere, to hell with the fuel, you'd propably save your company money. However, unless you are given the numbers, we will never know!


Pontius's Copilot
8th Jun 2007, 21:59
Fuel almost certainly will be; but perhaps you you work for a European (franco-dutch?) flag-carrier, where staff/social costs & working practices may be more expensive.