Abnormal Attitude Law — the Upset-Recovery Law and Why It Doesn't Reset to Normal
If the aircraft is thrown far outside the normal envelope into an extreme attitude, the EFCS switches to the abnormal attitude law — a recovery configuration giving the PF maximum efficiency to regain a normal attitude. It is the system's automatic response to a developed upset, and its defining trap is that once recovered it does not go back to Normal law — it stays degraded for the rest of the flight.
If for any reason the aircraft goes far outside the normal flight envelope and reaches an extreme attitude, the flight control law will be modified. The abnormal attitude law will engage and will provide the PF with maximum efficiency to recover normal attitude. — FCOM DSC-27-20-20-40
1. What an upset is — and where this law fits
Per FCTM PR-AEP-MISC, "an aircraft upset is an undesired aircraft state characterized by unintentional divergences from parameters normally experienced during operations," involving pitch and/or bank-angle divergences and possibly inappropriate airspeeds for the conditions; it "exists any time an aircraft diverges from what the flight crew is intending to do," and the divergence grows until the crew (or auto-flight, or natural reaction) stops it.
[!note]- The abnormal attitude law is the EFCS's automatic answer to a developed upset (integrative synthesis) An upset is a divergence from intent (FCTM PR-AEP-MISC); the Normal-law protections are designed to prevent one developing. If a divergence becomes extreme anyway (gust, mishandling, wake), the EFCS reconfigures to the abnormal attitude law to give the PF the most direct, full-authority control to recover (FCOM DSC-27-20-20-40). So this law is the recovery configuration that takes over when prevention has been overwhelmed — and the crew flies the upset-recovery technique within it.
2. When it engages
Per FCOM DSC-27-20-20-40, the abnormal attitude law engages when any one of these is reached:
| Parameter | Threshold |
|---|---|
| Pitch (≥2 ADCs valid & consistent) | > 50° nose-up or < 30° nose-down |
| Pitch (otherwise) | > 40° nose-up or < 20° nose-down |
| Bank | > 125° |
| Angle of attack | > 40° |
| Speed | > 440 kt or < 60 kt |
| Mach | > 0.96 or < 0.1 |
[!note]- The pitch thresholds depend on air-data validity (integrative synthesis) With ≥ 2 valid, consistent ADCs the trigger is 50° up / 30° down; with degraded air data it is the lower 40° up / 20° down (FCOM DSC-27-20-20-40). With less-trustworthy data the system engages the recovery law earlier — the same air-data dependence seen in ALT 2. These are genuinely extreme values: an everyday divergence does not reach them; this is for a fully developed loss of control.
3. What it does — pitch alternate, roll direct, yaw mechanical
Per FCOM DSC-27-20-20-40, when the abnormal attitude law engages:
- pitch alternate law active;
- roll direct law active;
- yaw mechanical law active;
- autotrim not available → USE MAN PITCH TRIM on the PFDs;
- F/CTL ALTN LAW on the ECAM.
[!warning]- It is built for control authority, not protection The combination — pitch alternate, roll direct, yaw mechanical, no autotrim — strips the law down to give the PF the most direct, full-authority control to recover (FCOM DSC-27-20-20-40). There are no protections fighting the recovery inputs — which is appropriate, because in a recovery the crew may need to roll the shortest way and unload the wing without a protection limiting them. The PFD also declutters at extreme attitudes (bank > 45°, pitch beyond 25° NU / 13° ND) and shows large red arrowheads pointing the way to reduce the attitude (PFD, DSC-31-40).
4. Why it doesn't reset to Normal law
When the aircraft returns within the normal flight envelope, the abnormal attitude law disengages and the following conditions remain for the remainder of the flight: pitch alternate law is active with autotrim, roll direct law is active, yaw alternate law is active, F/CTL ALTN LAW is displayed on the ECAM.
Per FCOM DSC-27-20-20-40, on recovery the abnormal attitude law disengages, but the system does not restore Normal law — for the rest of the flight it holds:
- pitch alternate law (with autotrim restored);
- roll direct law;
- yaw alternate law;
- F/CTL ALTN LAW on the ECAM.
[!warning]- Recovery leaves you in alternate/direct for the rest of the flight — plan the approach for it This is the operational consequence: surviving an upset does not give Normal law back (FCOM DSC-27-20-20-40). You land in pitch alternate + roll direct, with autotrim restored but no protections and a direct, sensitive roll (12/13). The crew must brief and fly the approach as a degraded-law landing — small lateral inputs (roll is direct), manage speed/AOA manually (no protections), and note pitch trim is automatic again after recovery (unlike during the upset, when it was manual).
5. Counterintuitive points
[!warning]- The thresholds are extreme and air-data dependent Pitch > 50°/30° (or 40°/20° on degraded ADC), bank > 125°, AOA > 40°, > 440/< 60 kt, Mach > 0.96/< 0.1 (FCOM DSC-27-20-20-40) — only a developed upset reaches them.
[!warning]- Autotrim is OFF during the upset, ON again after recovery During abnormal attitude: USE MAN PITCH TRIM (no autotrim); after recovery: pitch alternate with autotrim (FCOM DSC-27-20-20-40).
[!warning]- The law removes protections on purpose — to allow the recovery No protection limits the recovery inputs; the PFD red arrowheads show the way out (FCOM DSC-27-20-20-40 / DSC-31-40).
6. Self-test
[!note]- Q1. What is an upset, and how does the abnormal attitude law relate to it? An undesired state — unintentional pitch/bank divergences from intent (FCTM); the abnormal attitude law is the EFCS's automatic recovery configuration when a divergence becomes extreme.
[!note]- Q2. Name the engagement thresholds. Pitch >50°/<30° ND** (≥2 ADC) or **>40°/<20° ND**; bank **>125°; AOA >40°; speed >440/<60 kt**; Mach **>0.96/<0.1.
[!note]- Q3. What laws are active during the abnormal attitude law? Pitch alternate, roll direct, yaw mechanical, no autotrim (USE MAN PITCH TRIM), F/CTL ALTN LAW.
[!note]- Q4. What remains after recovery, and for how long? Pitch alternate (with autotrim), roll direct, yaw alternate — for the rest of the flight (Normal law is not restored); plan a degraded-law approach.
7. Key takeaways
| Point | Detail |
|---|---|
| Upset | undesired state — unintentional pitch/bank divergence from intent (FCTM) |
| Engage | pitch >50/30 (≥2 ADC) or 40/20; bank >125°; AOA >40°; >440/<60 kt; Mach >0.96/<0.1 |
| Active | pitch alternate, roll direct, yaw mechanical, no autotrim → USE MAN PITCH TRIM; F/CTL ALTN LAW |
| PFD | declutter at extreme attitude, red arrowheads to reduce attitude |
| After recovery | pitch alternate (autotrim), roll direct, yaw alternate — rest of flight |
| Key point | Normal law not restored; no protections limit the recovery; plan a degraded-law approach |
References
- FCOM DSC-27-20-20-40 (Reconfiguration Control Laws — Abnormal Attitude Laws) — engages on extreme attitude: pitch > 50° NU / < 30° ND (≥2 ADCs valid & consistent) else > 40° NU / < 20° ND, bank > 125°, AOA > 40°, speed > 440 kt or < 60 kt, Mach > 0.96 or < 0.1; when engaged pitch alternate + roll direct + yaw mechanical, autotrim unavailable (USE MAN PITCH TRIM), F/CTL ALTN LAW on ECAM; on return to normal envelope disengages but for the remainder of the flight retains pitch alternate (with autotrim) + roll direct + yaw alternate, F/CTL ALTN LAW.
- FCTM PR-AEP-MISC (Upset Prevention and Recovery) — an upset is an undesired aircraft state of unintentional divergences (pitch and/or bank, possibly inappropriate airspeeds); exists whenever the aircraft diverges from crew intent; divergence grows until stopped by crew, auto-flight or natural reaction.
- FCOM DSC-31-40 (PFD) — at bank > 45° / pitch > 25° NU or 13° ND the PFD declutters to attitude/speed/heading/altitude/VS; beyond 30° large red arrowheads indicate the direction to reduce attitude; returns to normal below 22° NU / 10° ND and 40° bank.
Independent study material, not an Airbus publication and not endorsed by the manufacturer. Always defer to the current operator FCOM, FCTM, and QRH for operational use.