Given that the thread started with a DA40, here are my SOPs in a DA40 and would like to have them commented/critiqued for pros and cons:
My main reason in a DA40 for setting a further stage of flaps (from T/O to LDG) during the final stage of the approach is that the LDG flaps extension speed is limited to 91 kts and I normally fly instrument approaches at 100 kts to have a reasonable speed.
I set flaps to T/O on the intermediate approach leg to control speed and have more of a nose-down attitude to help me when transitioning from IMC to VMC. Setting T/O flaps limits me to 108 kts which is the T/O flaps extension speed, which is why I fly my instrument approaches at 100 kts.
I then set flaps to LDG when I have decided to go for a landing but not higher than 500 ft to maintain the higher approach speed. This does require configuration changes (reduce throttle, increase AoA to bleed off speed, set LDG flaps) but I have not found that to be particularly destabilising the approach. The only way to avoid the configuration changes is to fly the final approach below 91 kts. I personally avoid changing configuration whilst flying the approach itself until committed to land (when breaking out of IMC but not higher than 500ft, i.e. at a height of 200-500 ft) as I am busy enough concentrating on the localiser and glideslope needles and don’t need a distraction then.
That way I always have the same configuration when landing (which is then by definition always in VMC) and for a potential go-around in VMC. It does mean having a different configuration for go-arounds in IMC. Again, I have not found that to be an issue as my steps are: full throttle whilst lifting nose, establish a positive rate of climb, monitor speed and climb rate. I start only focusing on what to do with flaps as soon as I have established a stable and confirmed climb.
For IFR I use 7-5-3, meaning distance on final for flap1/gear/flap2. When not on autopilot (checkride), I would reconfigure fully before intercepting GS.
Flap change at DA sounds exotic. I aim to fly at a stable speed down to threshold. As for landing with TO flap, I would argue that there should be one go around procedure not requiring the pilot to memorize which flap setting he used.
I always try to minimize my workload.
On the 172 I would:
- extend the first stage of flaps when at downwind altitude (VFR) or when at procedure altitude (IFR)
Last altitude before descent means stage 1 of flaps. It reduces the workload because when you level off and when you extend the flaps, you have to adjust trim pitch and power. Leveling off and extending the flaps at the same time saves one reconfiguration procedure.
- extend the second stage of flaps when I begin the descent
Descent means stage 2 of flaps
- extend the last stage 3 of flaps when I make the decision to land. It would be deciding to continue below DA in IFR. In VFR it depends on the circumstances.
Decision to land means stage 3 of flaps.
Linking one event to an action reduces the risk to forget to perform the said action.
Of course I don’t always to that, especially when flying VFR. But each time I feel tired, or under pressure for any reason, I get back to my basic procedures to reduce the risk of forgetting something.
pilotrobbie wrote:
I guess so, but at what heights do you do for the following?
Full flap before touchdown. In IMC if there’s no traffic all parameters/configuration/checklist completed by 500ft AAL is a good gate.
Yes; you have to push the yoke forward a lot when you go to Flap 2, but every TB pilot (who is awake) will know that. If you don’t do that, you baloon upwards, and if you do it at minima, just below the cloudbase, you are likely to get back into IMC…
If you go Flap 2 with the KFC225, it still works but will probably baloon up some 100ft above the glideslope, before it gets back onto it again (I have tested this, and it is impressive, despite looking really dirty).
And yes the trimmed speed changes a lot too, but if you go to Flap 2 at say 100kt, that is OK.
Peter wrote:
I always land with full flaps – per the POH
That depends on the trim changes when you extend flaps. It was so long ago that I flew the TB20 that I don’t remember if there are noticeable trim changes when you extend flaps, but with a Cessna 172 et.al. there is a strong change. At least with a rate based A/P you have to be very careful extending or retracting flaps with the A/P engaged. Just shoving the flap lever to the desired position will not do.
Fair point on the gear-down protection, how does it work? why they can’t have it on allflap stages?
The gear down warning or auto-extension is it coming from an external pitot tube on the TB20?
I always land with full flaps – per the POH 
The other reason is that if you land with half flap, you lose one of the gear-up-landing protections (the other one being on the throttle lever position, and that one is defeated when landing normally into a strong headwind). Many of the TB20/21 gear up landings took place in the US where this half-flap practice is widespread due to loads of long tarmac runways.
pilotrobbie wrote:
So you never land in IMC with flaps full? Just t/o flaps. What sort of speeds do you use in reference to the Flight Manual?
I know you didn’t ask me, but I also never land off an instrument approach with full flaps. If the AFM/POH doesn’t provide approach speeds for partial flap, I use 1.3*Vs0.
@Noe that speed grid looks far difficult to remember
DA40 is probably one of those aircraft with high “Speed Range/Power Range” (you can add a Mooney to this list) but I am still not sure if rounding those numbers to the nearest +/-5kts helps?
