Setting Up the Approach (PERF APPR)
PremiumintermediateThe approach briefing, in the box: QNH, wind, temperature, VAPP and minima for the ILS onto Heathrow's 27R.
What this scenario covers
PERF APPR is the last of the phase-based performance pages, and it collects everything the FMGS needs to fly and protect the approach: the destination QNH and temperature, the surface wind, the transition altitude, the approach speed VAPP, and the minima — baro or radio, depending on the approach.
VAPP is the one the aircraft cares about most. It is computed from the landing configuration and weight, with a wind additive, and it becomes the managed speed target on final.
How it applies in flight ops
This page is filled during the approach briefing, well before top of descent, because it is the moment the crew agrees what they are going to fly and at what numbers. Doing it late is a workload trap — the descent is the busiest part of a short-haul flight.
Setting the minima has a specific consequence: it drives the automatic callouts and the approach protections. Minima entered as a decision height when the approach is flown to a decision altitude is the kind of quiet mismatch that briefings exist to catch.
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Everything about this scenario is on this page, steps included — reading it costs nothing and always will. What Premium adds is doing it: the MCDU validates every entry as you make it, tells you when an entry was accepted but wrong, and saves your progress across devices.
Step-by-step: Setting Up the Approach (PERF APPR)
- You're in the descent and ATIS reports QNH 1013, wind 270/10, +15°C. From the PERF page, press NEXT PHASE> until the title shows APPR.
PERF has five phases. Each is filled in at the right moment: TO before pushback, CLB after takeoff, CRZ at top of climb, DES on descent prep, and APPR before the final approach briefing. Setting APPR too early is fine — the FMS uses these values as soon as you arm APPR mode on the FCU.
- Enter the QNH from ATIS. Type 1013 and press 1L.
QNH is the local sea-level pressure. Setting it on PERF APPR feeds it to the FMS for landing performance calculations. You also set it on the standby altimeter and FCU baro at transition level — they're separate inputs.
- Enter the surface temperature. Type 15 and press 2L.
Approach temperature affects density, true airspeed, and engine performance. The FMS uses it together with QNH to compute correct GPATH and VAPP. ATIS gives you this number directly — never guess or copy yesterday's value.
- Enter the magnetic wind 270/10. Type 270/10 and press 3L.
This is the wind at the threshold, magnetic, in knots — exactly what the tower will give you. The FMS uses it to compute headwind/crosswind components and the VAPP wind correction. With RWY 27 and wind 270, that's a 10-kt direct headwind.
- Set transition altitude to 6000 for London TMA. Type 6000 and press 4L.
Transition altitude is where you switch from QNH to standard 1013 on climb (or back the other way on descent). It varies by country and FIR — the UK is moving towards a unified 18000 ft eventually, but London TMA stays at 6000 ft today. Setting it correctly lets the FMS draw the magenta transition arrow on the ND in the right place.
- Enter VAPP 140 kt. Type 140 and press 5L.
VAPP = VLS + wind correction. The correction is one-third of the tower-reported headwind component, bounded between +5 and +15 kt. With a 10-kt headwind: 1/3 = 3.3, below the +5 minimum so VAPP = VLS + 5. The FMS computes this for you when GW is known, but you can override here. At a representative landing weight near 65 t with FULL flaps, VLS sits around 135 kt and VAPP comes out to 140 kt.
- Enter BARO minima 280 ft (DA for ILS CAT I, RWY 27R). Type 280 and press 2R.
BARO is the altimeter-based decision altitude. EGLL RWY 27R has TDZE ≈ 79 ft, so CAT I DA ≈ 279 ft (we round to 280). It's the altitude at which you must have the runway in sight on a precision approach, otherwise go around. BARO triggers the "MINIMUM" callout from the FMS.
- Enter RADIO 200 ft (CAT I DH). Type 200 and press 3R.
RADIO is the radar-altimeter-based decision height. Some operators set both BARO and RADIO; some set only one. For a CAT I ILS, RADIO 200 ft is the universal ICAO floor (Annex 6). For CAT II it drops to 100 ft, CAT III A to 50 ft, CAT III B/C to zero or no DH. Type NO if your SOP wants RADIO disabled.
What to take away
- PERF APPR carries QNH, temperature, wind, transition altitude, VAPP and minima.
- VAPP comes from landing weight and configuration plus a wind additive.
- Fill it during the briefing, before top of descent — not on the way down.
- The minima you enter drive the callouts; enter the right kind for the approach flown.