Operating Limitations — Speeds, Weights, Load Factor and Wind

Aircraft General and Ground Geometry described what the aircraft looks like. This article covers the other half of "Aircraft General": its envelope — how fast is overspeed, how heavy is too heavy to take off or land, how many g before the structural limit, and what crosswind or tailwind is the red line.

Limitations are the one layer of FCOM that must not be violated. A description can be understood "roughly"; a limit is a hard boundary, and some of them are AFM certification limits — legal, not advisory. FCOM files the limits that belong to the whole aircraft (not to any single system) as LIM-AG (Limitations — Aircraft General):

                LIM-AG — the whole-aircraft red lines
   ┌──────────┬──────────┬──────────────┬──────────────┬──────────┐
   load factor  freighter     operational        speeds          weights
   F_CTL        FRE           parameters (OPS)    SPD             WGHT
   │            │             │                   │               │
  -1/+2.5 g   ≤12 occupants  env envelope        VMO/MMO (no      MTW/MTOW
  (clean)     MDCC access    (min TAT -53)       numeric value)   MLW/MZFW
  0/+2 g      (prohib. taxi/ crosswind 32/45     VLE/VLO 250/.55  min weight
  (other)     TO/landing)    tailwind 15/10      gravity gear 200 ↑several
                             door wind 40/50/60  ground speed 204   certified
                             runway/surface tab  VMCL/VMCA/VMCG     weight
                                                 window/wiper 230   variants

[!warning]- Almost all of LIM-AG is written numbers, not figures Unlike DSC-20 (mostly drawings), LIM-AG is nearly all stated values and tables, so it can be quoted verbatim throughout. Only the full OAT/altitude environmental envelope and the MZFW-versus-take-off-weight trade curve are figures. Where FCOM lists several certified weight or speed variants, take the set that applies to the aircraft you fly from its FCOM/AFM — the values below are representative and, where a range is shown, span the published variants.

1. Weights (LIM-AG-WGHT)

FCOM publishes several certified weight variants (maximum taxi weight of 238 900 kg and 242 900 kg, each with its own maximum landing and zero-fuel weights). Representative published values, spanning the variants:

Two mechanisms sit alongside the numbers:

"Maximum Zero Fuel Weight (MZFW) can be increased provided Actual Takeoff Weight is decreased as shown in the following graph."

MZFW and take-off weight trade against each other; the exact exchange is a graph.

"In exceptional conditions (inflight turn back or diversion), an immediate landing at weight above maximum landing weight is permitted, provided that the pilot follows the overweight landing procedure."

MLW is a hard boundary but not absolute — a turn-back or diversion may land above it, at the price of the overweight-landing procedure (FCTM/QRH).

Learning hook. MTW exceeds MTOW by the fuel burned taxiing to the runway. MLW is the red line, but it yields to a turn-back/diversion via the overweight procedure. Because several weight variants exist, always take the set for the aircraft you fly — do not mix a low-MTOW variant's landing weight with a high-MTOW take-off weight.

2. Speeds (LIM-AG-SPD)

Maximum operating speed VMO/MMO. A trap for the unwary — FCOM states the principle but prints no numeric value here:

"The flight crew may not deliberately exceed the maximum operating speed limits VMO/MMO in any regime of flight."

The numeric VMO (kt) / MMO (M) are not in LIM-AG text (they are on the PFD speed scale / red-and-black barber pole, and in the performance material). This article does not supply a number for them.

Landing-gear speeds (verbatim values):

Maximum speed with landing gear extended (VLE) = 250 kt / 0.55; landing-gear operating speed, extension and retraction (VLO) = 250 kt / 0.55; maximum speed for landing-gear gravity extension (VLE/VLO) = 200 kt.

Gravity extension is limited to 200 kt (below the normal 250) — the free-fall path is more fragile, tying to gravity gear extension in ATA-32.

Maximum ground speed 204 kt (tyre / ground-roll limit).

Maximum flap/slat speeds (VFE), by configuration:

Minimum control speeds (VMCL/VMCA/VMCG). FCOM gives two sets, for a lighter and a heavier variant. Representative (lighter) set — VMCL:

VMCL (landing minimum control speed) = 118 kt (IAS).

A second, higher set (VMCL 126 kt; VMCG 121 kt at sea level) applies to a heavier variant — take the set that matches the aircraft.

Cockpit window open maximum speed 230 kt, with a coupling to pressurisation:

"It is not possible to open the cockpit windows, with the packs ON."

Wiper maximum operating speed 230 kt.

3. Flight maneuvering load (LIM-AG-F_CTL)

Clean configuration: "-1 g to +2.5 g"; other configurations: "0 g to +2 g".

Learning hook. Clean is −1/+2.5 g (the standard transport envelope); the moment slats/flaps are out, the lower limit rises to 0 g — no negative load factor, protecting the high-lift structure. These two numbers are the hard boundary behind the fly-by-wire load-factor protection in ATA-27.

4. Airport operations and wind (LIM-AG-OPS)

Runway geometry. Runway slope (mean) ±2 %; nominal runway width 45 m.

[!warning]- Revision change: runway-altitude limit deleted Earlier revisions listed a runway-altitude limitation (12 500 ft). The current FCOM revision has removed it (per the Summary of Highlights). Follow the current revision — the item is no longer a hard limit.

Crosswind and tailwind (dry-runway certified/demonstrated values):

Take-off: "Maximum certified crosswind for takeoff" … "32 kt (gust included)", and "It is an engine limitation." Landing: "Maximum demonstrated crosswind for landing" … "45 kt (gust included)", which "is not an Airplane Flight Manual (AFM) limitation : It is the maximum crosswind condition experienced during the aircraft certification campaign."

The legal distinction is the exam point: the take-off crosswind is a hard AFM limit (may not be exceeded); the landing crosswind is only a demonstrated value (advisory). (A 40 kt demonstrated landing value applies to another variant.)

Passenger/cargo door operation in wind:

The maximum wind for passenger-door operation is 40 kt (or 50 kt if the nose is into the wind); for forward and aft cargo doors 40 kt (or 50 kt nose-into-wind or doors on the downwind side); doors must be closed before the wind exceeds 60 kt.

Maximum recommended crosswind on wet and contaminated runways (by surface / runway condition code):

"The maximum crosswind values given in the above table are recommended values based on computations."

Learning hook. Dry take-off crosswind is 32 kt (a hard limit); as the surface degrades the crosswind red line steps down to 15 kt on ice. This gradient and the "add margin on a wet/contaminated runway for the 180° turn" note in Ground Geometry are the same logic — a poor surface tightens every lateral margin at once.

5. Environmental envelope (LIM-AG-OPS)

Minimum total air temperature (TAT) = -53 °C.

The full OAT/altitude envelope is a figure; only the TAT floor is stated in text. The −53 °C floor bears on fuel freezing and probe/system low-temperature operating boundaries. The rest is not reproduced here.

6. Freighter operations (LIM-AG-FRE)

Applies to the freighter variant (the passenger aircraft is the teaching baseline):

• Cabin occupancy — "The cabin maximum occupancy is 12 occupants"; each occupant must be briefed before flight (emergency egress, oxygen, turbulence, flight-deck/cabin communication, any national-authority item) and be physically able to perform the emergency procedures.
• Access to the main deck cargo compartment (MDCC) — permitted for crew and authorised occupants only under conditions: Class E cargo-compartment procedure training; a portable oxygen bottle with full-face mask carried and connected at all times; notify the crew before entering and after leaving; close the access door immediately; return to the cabin at once on decompression, turbulence or smoke. Critically:

"Access to the Main Deck Cargo Compartment is prohibited during taxi, takeoff and landing."

This ties to the freighter main-deck cargo firefighting (Class E, depressurisation).

7. How the limits are used

1. Take the right variant set. Weights and minimum control speeds both come in variants. Match the weight set and the VMC set to the aircraft — mixing them is the classic error.
2. Know the legal grade of a limit. The take-off crosswind (32 kt) is an AFM hard limit; the landing crosswind (45 kt) is only demonstrated. Same word "crosswind," different authority.
3. Where the source is silent or changed, say so. VMO/MMO carry no numeric value in LIM-AG (do not invent one); the runway-altitude limit was deleted in the current revision. Limits move with revisions — always use the current book.
4. Limits interlock. Over MLW → overweight-landing procedure; VFE exceeded → structure; gravity gear 200 kt → ATA-32; window won't open with packs ON → ATA-21 pressurisation; 0/+2 g → ATA-27 protection. A limit is a system boundary aggregated at the whole-aircraft level.

Self-test

[!note]- Q1. Why does FCOM list more than one set of weights, and what is the risk? Several certified weight variants exist (MTW 238 900 or 242 900 kg, with matching MLW/MZFW). The risk is mixing a low-MTOW variant's landing/zero-fuel weight with a high-MTOW take-off weight — always take one consistent set for the aircraft.

[!note]- Q2. Can you land above maximum landing weight? Under what condition and at what cost? Yes, in exceptional conditions (inflight turn-back or diversion) an immediate landing above MLW is permitted, provided the overweight-landing procedure is followed.

[!note]- Q3. Does FCOM give a numeric VMO/MMO in LIM-AG? How do you correct a student who quotes a figure from memory? No — LIM-AG states only "may not deliberately exceed." The number is on the PFD speed scale / performance material, not here. Do not supply one from memory; the sourcing discipline is "if the book doesn't state it, don't invent it."

[!note]- Q4. VLE, VLO and gravity-extension speeds? Why is gravity extension lower? VLE and VLO 250 kt / 0.55; gravity extension 200 kt. Gravity (free-fall) extension is limited lower because that path is more fragile than normal hydraulic extension.

[!note]- Q5. Take-off crosswind 32 kt versus landing crosswind 45 kt — what is the difference in legal nature? Take-off 32 kt is an AFM certification limit (an engine limitation) that may not be exceeded; landing 45 kt is only a demonstrated value (the maximum experienced in certification), advisory rather than a hard limit.

[!note]- Q6. Clean and flapped load-factor limits? Why does the lower limit change with flaps out? Clean −1 to +2.5 g; other configurations 0 to +2 g. With high-lift devices extended, negative load factor is not permitted (lower limit 0 g) to protect the high-lift structure.

Key takeaways

References

• Per FCOM LIM-AG-WGHT — weight limitations (variant sets), MZFW increase versus take-off weight, overweight-landing exception.
• Per FCOM LIM-AG-SPD — VMO/MMO principle (no numeric value), VLE/VLO 250 kt/0.55, gravity extension 200 kt, max ground speed 204 kt, flap/slat VFE table, VMCL/VMCA/VMCG (two variant sets), cockpit-window and wiper 230 kt.
• Per FCOM LIM-AG-F_CTL — flight maneuvering load acceleration limits (clean −1/+2.5 g; other 0/+2 g).
• Per FCOM LIM-AG-OPS — runway slope ±2 %, nominal width 45 m, crosswind (take-off 32 kt certified / landing 45 kt demonstrated), tailwind 15/10 kt, door wind limits, wet/contaminated crosswind table; environmental envelope minimum TAT −53 °C; runway-altitude item deleted in the current revision (Summary of Highlights).
• Per FCOM LIM-AG-FRE — freighter cabin occupancy (max 12) and main-deck cargo compartment access conditions.

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.