Embraer E-Jet Ice and Rain Protection

The Embraer E190-E2 protects itself against ice in two ways. Hot engine bleed air keeps the engine cowls and the outboard wing slats free of ice, and AC electrical power heats the windshields and the air data and temperature probes. With the anti-ice MODE in AUTO, ice detectors on the nose switch the bleed-air anti-ice on and off by themselves, and wipers clear rain from the windshields.

Figures are those of the E190-E2 unless the first-generation E190, the E190 E1, is named. The bleed air supply is described in E-Jet air conditioning, bleed air and pressurisation, and the principles in ice protection and ice detection, thermal anti-icing and probe heat, window heat and rain protection. For the A320's arrangement, see A320 bleed air and ice protection.

Ice detection and icing conditions

The E190-E2 has two ice detectors, probes on the left and right of the nose section, connected to the MAU. When ice is detected the ICE CONDITION advisory appears, and the probe is heated for a few seconds.

Ice can accumulate at 10 °C or below when moisture is present, so these are the icing conditions the procedures guard against. The 10 °C figure recurs throughout: it sets the take-off anti-ice selection and the action after a double detector failure.

A single detector failure does not stop the system working: the anti-ice, including its automatic activation, still works, but the checklist calls for manual mode. Only when both detectors have failed and the OAT is 10 °C or below must the crew select MODE ON, and they keep it on until 2 minutes after leaving icing conditions.

Anti-ice modes

The anti-ice MODE selection decides when the bleed-air anti-ice runs:

In MODE ON the A-I MODE NOT AUTO advisory is displayed. On the ground with both engines running, MODE ON gives engine anti-ice at once, while wing anti-ice waits until the aircraft is airborne.

For take-off the crew also set the REF A/I on the MCDU TRS page, with the MODE in AUTO or ON:

With REF A/I at ENG or ALL, the anti-ice comes on when the wheel speed exceeds 30 kt (40 kt on the E190 E1) and stays on until 1,700 ft/2 min, after which it returns to AUTO.

APU bleed cannot be used for anti-ice. If REF A/I is ENG or ALL for a take-off with APU bleed, or ice is detected during such a take-off, the APU bleed valve closes and the packs switch off.

Wing anti-ice

Bleed air heats the three outboard slats on each wing, six slats in all. The inboard slats are not anti-iced and, unlike the EMB 145, the E190-E2 has no horizontal stabiliser anti-ice.

If a bleed source is lost while the wing anti-ice is operating, the cross-bleed valve opens automatically, with no crew action. The APU bleed never takes over, because APU bleed is not used for anti-ice in any case.

After take-off a 60-second built-in test (BIT) checks the anti-ice system. It shows the A-I WING VLV OPEN status message and the MFD anti-ice synoptic page. On the E190-E2 it runs at 10,000 ft AGL and at least 2 minutes after lift-off; on the E190 E1 it runs 10 minutes after take-off or at 10,000 ft AGL, whichever comes first.

Engine anti-ice

Each engine's anti-ice valve is electrically controlled by the air management system (AMS) and pneumatically operated, and it needs electrical power to stay closed. Open, it sends engine bleed air to a piccolo tube around the cowl.

A-I ENG 1 (2) FAIL, a caution, means that the engine anti-ice valve is closed although commanded open, or that a duct has failed.

View full schematic

Windshield and probe heating

AC electrical power heats the windshields, the four air data smart probes (ADSP) and the two total air temperature (TAT) probes. The engine cowls and outboard slats are the bleed air's job; the inboard slats and the horizontal stabiliser are not protected at all.

Each windshield side has three heat sensors: one for control, one to detect overheat and a spare. WINDSHIELD 1 (2) HTR FAIL, a caution, means that the heating of that windshield has failed or overheated.

With only one AC power source available, windshield heating is inhibited on the ground. In flight only the left windshield is heated, or the right one if the left heating has failed, and the warm-up self-test then takes 120 seconds.

Rain protection

The windshield wipers run on 28 V DC. LOW gives 80 cycles a minute, HIGH 125 and TIMER one cycle every 8 seconds, with the right wiper synchronised with the left. The wipers are not available in the electrical emergency.

When the windshield is dry, a wiper's motor stalls and the wiper shuts down automatically; selecting OFF resets it.

On the E190 E1 the wipers may be operated up to 253 KIAS; for the E2 the limitation is a maximum altitude of 14,000 ft. The wipers are required for CAT II approaches.

Ice speeds

The E2 has ice speeds, flagged by the STALL PROT ICE SPEED message. Once they are in use, they can be reset only when no icing conditions are detected, there is no ice accretion and the SAT is 5 °C or above. Transport Canada's operational evaluation report lists the ICE SPEED RESET function on the ICE PROTECTION panel among the features that are new on the E2.

Anti-ice through a flight

Before take-off the crew compare the OAT and the moisture with the REF A/I table. At 3 °C in rain, for example, they set ALL on the MCDU TRS page, with the MODE in AUTO. If the packs are running on APU bleed for the take-off, that choice also closes the APU bleed valve and switches the packs off, since APU bleed cannot feed the anti-ice.

During the take-off roll the anti-ice comes on as the wheel speed passes 30 kt, and it stays on until 1,700 ft/2 min, when it returns to AUTO. From then on the ice detectors decide: when ice is detected, ICE CONDITION appears and engine and wing anti-ice come on, and when ice is no longer detected they stay on for another 2 minutes. At 10,000 ft AGL, and at least 2 minutes after lift-off, the 60-second BIT runs, with A-I WING VLV OPEN and the anti-ice synoptic page on the MFD. If a bleed source is lost while the wing anti-ice is working, the cross-bleed valve opens by itself.

A detector failure changes the picture only in part. With one detector failed, the anti-ice still works automatically and the crew follow the checklist into manual mode; with both failed and the OAT at 10 °C or below, MODE ON stays selected until 2 minutes after leaving icing conditions. Once STALL PROT ICE SPEED has appeared, the ice speeds can be reset only when no icing conditions are detected, no ice accretion remains and the SAT is at least 5 °C. In rain on the approach the wipers may be used up to 14,000 ft, and they are required for a CAT II approach. The engine idle settings in icing are covered in E-Jet engines and APU, and ground de-icing in aircraft ground de-icing and anti-icing.

Messages and limitations

Library articles are written for study and exam preparation. They do not replace your aircraft's approved documentation, your operator's procedures or the regulations themselves.