Another way to put it: by delaying gear retraction, you’re reducing the performance margin that you may need in a contingency. In other words, you’re making the takeoff less safe than it could have been, unless you can show a safety benefit for delaying gear retraction.
I see what you mean, but this is a completely other discussion!! This is a discussion about safety vs. commercial considerations and efficiency. We are all allowed to have our personal opinion about that matter, but the rules are the rules.
Since NOT retracting gear has already been accounted for,
the requirements for all eventualities have already been covered.
What you are saying is basically this:
If an engine fails, AND a mistake is made (like not following the engine failure contingency procedure), then the difference between having had the gear extended might get you into trouble.
That is true, but we have loads of such procedures that reduces margin. Some obvious are:
- Reduced takeoff thrust.
- Fuel tankering
There are indirect reductions in margin as well:
- Flying with a full passenger load (empty aircraft performs better).
This is such a procedure too:
- Flying with the gear extended is a commercial consideration (to reduce turnaround time).
An example to make this more palpable, 3 legs:
- You fly to Egypt with fuel tankering.
- You land at your destination with max landing weight in 45 deg C.
- You have 45 mins turnaround, and the brakes are allowed to be cooled sufficient to perform another takeoff.
- There after you fly a short 20 min to another Egyptian airport and land at max landing weight again in 45 deg C.
a) If you retract your gear during the short leg, accumulation of the heat from first and second landing will require a long brake cooling time, before you can leave again.
b) You fly with gear extended and you can make a quick turnaround between leg 2 and leg 3.
For leg 2 (the flight with gear extended), all requirements are being adhered to. All eventualities have been covered.
- The brakes were sufficient cool to reject a takeoff.
- For AEO with gear extended, I can safely follow applicable SID and adhere to the required climb gradient.
- For OEI, I can safely retract the gear and follow my contingency procedure (no need to apply MEL restrictions).
- In either case, my brakes are cool enough to allow for an immediate landing.
- If the gear is extended or not, only has a bearing on how long I have to wait before I can perform leg 3.
The above b) is a recommended procedure in my company...
Just to say that you will do what you want to do today because you are the pilot is a rather reckless approach to risk management, I suggest.
...but on the day, I decide what to do, as a captain. And I use available manuals as a tool to help manage the risk.
I am not doing anything illegal, I am not going to court or jail, and I won't be having tea and biscuits with anyone. Most likely I will be drinking my black coffee with my F/O on leg 3 back after a short turnaround.
P.s.
Regarding Cologne, you have to fly at V2 until reaching 4000 feet. Hence, there is no acceleration.