Performance Data Entry

intermediate
📍 Route: LEMD → EGLL⏱ ~3 minutes📊 8 steps🎓 Foundations

V-speeds, flap setting and a flex temperature for a Madrid departure — the numbers that decide whether the aircraft flies off the runway you have.

What this scenario covers

The PERF page carries the takeoff data: V1, VR and V2, the takeoff flap setting, and the flex temperature if a reduced-thrust departure is being made. These are not values the FMGS invents — they come from a performance calculation for today's weight, runway, wind, temperature and configuration, and the crew types them in.

The A320 splits performance by flight phase, so the takeoff page you are working on is one of a series (takeoff, climb, cruise, descent, approach) that the FMGS steps through as the flight progresses. Getting used to that structure now makes the descent and approach scenarios later feel familiar.

Route map for Performance Data Entry
The LEMD → EGLL route this scenario programs.

How it applies in flight ops

V1 is the decision speed: past it, the takeoff continues even with an engine failure, because there is no longer enough runway to stop. VR is where the pilot rotates, V2 the safety speed to fly if an engine quits. Those three numbers encode the whole runway analysis in a form the crew can act on in one second.

Because they are typed rather than computed on board, they are cross-checked. A transposed digit here is one of the classic sources of a takeoff performance incident, which is why airlines require both pilots to verify the entries against the same source document.

Start this scenario

Open the SimTuts A320 MCDU trainer and select “Performance Data Entry” from the scenarios list to walk through it step-by-step on the simulated keypad.

Open trainer →

Step-by-step: Performance Data Entry

  1. First, set up the route. Type LEMD/EGLL (Madrid to London) and press 1R.
  2. Go to the PERF page to enter takeoff performance data.

    All the values on this page come from a takeoff performance calculation — either from an EFB app, printed tables, or the airline's performance software. The calculation uses your actual takeoff weight, runway length, temperature, wind, and airport elevation to produce safe speeds.

  3. Enter V1 (decision speed) of 138. Type 138 and press 1L.

    Madrid Barajas has long runways (up to 4,350m), which allows lower V-speeds at similar weights. V1 = 138 here vs 145 at Heathrow reflects the different conditions. In practice, you'd calculate this fresh for every flight using your EFB.

  4. Enter VR (rotation speed) of 142. Type 142 and press 2L.

    VR is always at or above V1. The gap between V1 and VR gives a small buffer — after committing to takeoff at V1, you accelerate a few more knots before rotating.

  5. Enter V2 (takeoff safety speed) of 148. Type 148 and press 3L.

    V2 must be at least 1.13× the stall speed in takeoff configuration. The performance software computes this automatically. If you entered a wrong flap setting, V2 would change too.

  6. Enter flex temperature of 55. Type 55 and press 4R. Flex takeoff uses reduced thrust to save engine life.

    Flex (flexible) takeoff tells the engines to produce thrust as if it were 55°C outside (even if it's really 25°C). Hotter air = less thrust = less stress on the engines. Airlines use this to extend engine life and reduce maintenance costs. The max flex temp comes from your performance calculation. You can NEVER use flex on a contaminated runway or when performance is limiting.

  7. Set takeoff flaps to 2. Type 2 and press 3R. Madrid has long runways, so flaps 2 works well.

    Madrid's long runways allow Flaps 2, which produces less drag than Flaps 3 and gives better climb performance after takeoff. At a shorter runway you might need Flaps 3 for the lower speeds it allows. Your performance tables indicate which flap settings are valid for the conditions.

  8. Performance data complete. Press INIT to return to the main page.

What to take away

  • V1, VR and V2 come from a performance calculation, not from the FMGS.
  • Flap setting and flex temperature belong to the same takeoff data set.
  • PERF is phase-structured — takeoff now, approach much later, same page family.
  • Typed numbers get cross-checked; this is where transposition errors bite.

The rest of Foundations

Background reading

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