Embraer E-Jet Landing Gear, Brakes and Steering
The E-Jet landing gear system comprises the retractable tricycle landing gear with its controls, indications and alternate extension, the air/ground sensing that other systems use, the main wheel brakes with antiskid and autobrake, an emergency and parking brake, and nosewheel steering.
The Embraer E-Jets stand on a retractable tricycle landing gear: a steerable nose gear and two main gears, each main leg carrying an inboard and an outboard wheel. On the first-generation E190 the gear is electrically controlled and monitored by two redundant PSEMs, the units of the proximity sensor system, and it is moved by hydraulic system 2. On the E190-E2 the main wheel brakes are applied by wire, with pressure from hydraulic systems 1 and 2, and protected by antiskid and an autobrake that includes a rejected take-off mode. An emergency and parking brake and hydraulic nosewheel steering complete the system.
The two generations differ in many details, from the main gear doors to the warning thresholds, and the operating figures available are those of the E190 and the E190-E2. This article therefore names the model behind each figure: E190 E1 for the first-generation E190 and E190-E2 for its second-generation successor. The principles are covered in landing gear retraction and extension, anti-skid and autobrake and nose wheel steering, and the hydraulic supplies in E-Jet hydraulic system.
Landing gear and its operation
The crew select the gear with the landing gear lever. On the E190 E1 the PSEMs control and monitor the gear electrically and hydraulic system 2 moves it; hydraulic system 1 has no part in gear actuation and serves the outboard brakes instead. The E190 E1 lever has a lock, which DN LOCK REL overrides, and if the gear position still disagrees with the lever 20 seconds after the lever was moved, the LG LEVER DISAG warning message appears.
The main gear doors are one of the visible differences between the generations. On the E190 E1 each main gear door is mechanically connected to its leg and is open when the gear is down, and with the gear retracted the wheels remain uncovered. The E190-E2 has trailing-arm main gear with doors that fully cover the wheels.
| Gear speed | E190 E1 | E190-E2 |
|---|---|---|
| VLO, retraction | 235 KIAS | 220 KIAS |
| VLO, extension | 265 KIAS | 250 KIAS |
| VLE, gear extended | 265 KIAS | 265 KIAS |
The E190 E1 has a tyre speed limit of 195 kt. Like every tyre speed limit it is a ground speed, not an indicated airspeed, and it matches the 225 mph speed rating that the EASA type-certificate data sheet gives for the main tyres (see brake energy and tyre speed limits).
Exam tip: VLE, 265 KIAS, is the only gear speed the two generations share. The E190-E2's speeds for operating the gear are the lower ones: 220 KIAS to retract and 250 KIAS to extend.
Air/ground sensing
Many systems behave differently in the air and on the ground, so the air/ground signal matters well beyond the landing gear. On the E190 E1 the two PSEMs, housed in modular avionics units (MAU) 1 and 3, each monitor six weight-on-wheels (WOW) proximity sensors, two on each landing gear leg, as well as the uplock and downlock sensors.
The air/ground state is sensed from the compression of the gear shock absorbers. If a shock absorber does not extend fully after lift-off, the PSEM goes on signalling that the aircraft is on the ground, and every system that uses the air/ground signal is affected. On the E190-E2, weight on wheels also gates the ground functions of the gear: the nosewheel steering needs WOW to show the aircraft on the ground, and the RTO autobrake mode arms only with WOW on ground.
Gear indications and the LDG GEAR warning
In the E190 E1 gear position indication, a leg in transit is shown as an amber cross-hatched box. On the E190-E2 a flashing amber box goes with the LDG GEAR aural warning.
The LDG GEAR aural warning sounds when the gear is not down, under conditions that depend on the flap setting. With flaps 0 to 4 it needs two conditions together: a radio altitude below 700 ft, and at least one thrust lever retarded below a threshold angle that is higher with one engine inoperative. The thresholds differ between the generations:
| Flaps 0 to 4, gear not down, below 700 ft RA | E190 E1 | E190-E2 |
|---|---|---|
| One thrust lever below, all engines operating | 38° | 45° |
| One thrust lever below, one engine inoperative | 57° | 60° |
On the E190 E1 with flaps 5 or full, the warning sounds whenever the gear is not down, whatever the thrust and the radio altitude, and it cannot be silenced. The E190 E1's LG WRN INHIB, which inhibits the aural warning, may be used only when both radio altimeters have failed; with flaps 0 to 4 the warning logic depends on radio altitude.
On the E190-E2, the LG DOOR OPEN message calls for the gear to be left down: it must not be retracted.
Alternate gear extension
Besides the lever, the E190 E1 has two ways of lowering the gear:
- The ELEC OVRD switch, set to GEAR DOWN, is the second extension method. It commands the extension electrically and bypasses the PSEMs.
- The free-fall lever is the mechanical method, used after a hydraulic failure. It releases the hydraulic uplocks mechanically, and gravity extends the gear.
Once pulled, the free-fall lever is left in the up position. The gear can then no longer be retracted, and maintenance must be called.
Exam tip: after a free-fall extension on the E190 E1 the lever is left up and retraction is no longer possible. Maintenance must be called.
The E190-E2 has no ELEC OVRD switch. After an alternate gear extension it keeps its nosewheel steering, provided hydraulic system 2 is available.
Brakes and antiskid
On the E190-E2 braking is brake-by-wire: the brakes are commanded electrically and actuated hydraulically. Hydraulic system 1 supplies the outboard brakes and system 2 the inboard brakes, and hydraulic system 3 has no part in braking. On the E190 E1, too, system 1 supplies the outboard brakes.
Antiskid protection on the E190-E2 remains available during automatic braking, together with touchdown protection and locked-wheel protection. It is disabled below 10 kt, so that the aircraft can pivot on a wheel, and it is never available with the emergency/parking brake.
Locked-wheel protection compares the wheels in pairs: the two inboard wheels with each other, and the two outboard wheels with each other. If one wheel of a pair is turning 33 % slower than the other, the system commands zero brake pressure on the slower wheel. The function is disabled when the fastest wheel is below 30 kt.
Exam tip: the wheels compared are inboard with inboard and outboard with outboard, not the inboard and outboard wheels of one side. The release threshold is 33 % and the cut-off 30 kt.
The E190-E2 has no numerical brake temperature indication. Its brake temperature thresholds are:
| Brake temperature, E190-E2 | Indication |
|---|---|
| Below 232 °C | Green range |
| Above 420 °C, beyond the normal range | BRK OVERHEAT |
| Above 739 °C | LG TEMP EXCEEDANCE advisory: the aircraft cannot be dispatched |
Autobrake
The E190-E2 autobrake has a landing mode and a rejected take-off mode, RTO. Both start braking only when the wheel speed is above 60 kt and both thrust levers are at idle or in reverse.
RTO can be selected only on the ground. It arms when WOW shows the aircraft on the ground, the average wheel speed is below 60 kt and there are no failures. During a rejected take-off it activates as soon as the average wheel speed is above 60 kt with both thrust levers at idle or in reverse: a crew who reject at 90 kt and only retard the thrust levers get automatic braking without touching the pedals. Pressing a brake pedal above 60 kt disarms RTO.
With the landing mode armed, braking starts when both thrust levers are at idle or in reverse and the wheel speed is above 60 kt. The landing autobrake is disarmed by selecting OFF or RTO, by any brake pedal input, or by one thrust lever above idle.
Exam tip: in RTO, 60 kt works both ways: the mode arms below it and brakes above it. A pedal input above 60 kt disarms RTO, and in the landing mode any pedal input disarms the autobrake.
For the logic of other types, compare B737 landing gear and brakes and A320 landing gear, brakes and steering.
Emergency and parking brake
On the E190-E2 the emergency/parking brake is mechanically controlled and hydraulically actuated, with pressure from systems 1 and 2 through the dual EMG/PKG brake valve. It works independently of the brake control modules (BCMs), and it has no antiskid. Two separate accumulators give six full applications or 12 hours of parking brake use.
Two messages report its state:
- EMERG BRK FAULT, an advisory: low pressure in one accumulator, or a pressure disagreement between the inboard and outboard brakes.
- EMER BRK FAIL, a caution: low accumulator pressure together with low pressure in hydraulic systems 1 and 2.
Nosewheel steering
On the E190-E2 the nosewheel steering is controlled electronically by the nosewheel steering control module (NWSCM) and operated hydraulically, with power from hydraulic system 2 and DC bus 2. It needs WOW to show the aircraft on the ground and is disabled in flight.
The pilots steer with the rudder pedals or the hand wheel, whose authority falls as speed rises, though not in proportion to speed:
| Steering, E190-E2 | Maximum nosewheel angle |
|---|---|
| Rudder pedals | ±7° |
| Hand wheel, 10 kt or less | ±76° |
| Hand wheel, 26 kt | ±20° |
| Hand wheel, above 100 kt | ±7° |
| Free castor | ±170° |
If the steering is disengaged or faulty, or the nosewheel is turned beyond 76°, it reverts to free castor and can swivel through up to ±170°. Directional control then relies on differential braking and the rudder. After an alternate gear extension, the E190-E2 keeps its steering as long as hydraulic system 2 is available.
Exam tip: ±7° with the pedals, ±76° with the hand wheel at 10 kt or less, ±170° in free castor. Beyond 76° the nosewheel castors freely.
Messages and limitations
| Item | Model | Meaning or value |
|---|---|---|
| LG LEVER DISAG, warning | E190 E1 | Gear and lever disagree 20 s after the lever was moved |
| LG WRN INHIB | E190 E1 | Only with both radio altimeters failed |
| LG DOOR OPEN | E190-E2 | Leave the gear down |
| BRK OVERHEAT | E190-E2 | Brake temperature above 420 °C |
| LG TEMP EXCEEDANCE, advisory | E190-E2 | Brake temperature above 739 °C: no dispatch |
| EMERG BRK FAULT, advisory | E190-E2 | One accumulator low, or inboard/outboard disagreement |
| EMER BRK FAIL, caution | E190-E2 | Accumulator, HYD 1 and HYD 2 pressures all low |
| Tyre speed | E190 E1 | 195 kt ground speed |
Frequently asked questions
Which hydraulic systems power the E190 landing gear and brakes?
On the first-generation E190 the landing gear is electrically controlled by the PSEMs and moved by hydraulic system 2, while system 1 serves the outboard brakes. On the E190-E2 the brakes are applied by wire, with system 1 supplying the outboard brakes and system 2 the inboard brakes; system 3 has no part in braking. The E190-E2 emergency and parking brake also uses systems 1 and 2, and its nosewheel steering uses system 2.
How is the E190 landing gear lowered after a hydraulic failure?
On the E190 E1 the crew pull the free-fall lever, which mechanically releases the hydraulic uplocks so that gravity lowers the gear. The lever is then left up, the gear can no longer be retracted and maintenance must be called. The E190 E1 also has the ELEC OVRD switch, a different method: set to GEAR DOWN, it commands the extension electrically and bypasses the PSEM. The E190-E2 has no ELEC OVRD switch.
How does the RTO autobrake work on the E190-E2?
RTO can be selected only on the ground. It arms with weight on wheels showing the aircraft on the ground, an average wheel speed below 60 kt and no failures. It activates when the average wheel speed is above 60 kt and both thrust levers are at idle or in reverse, so retarding the levers in a rejected take-off starts the braking. Pressing a brake pedal above 60 kt disarms it.
What are the E190 landing gear speed limits?
On the first-generation E190 the gear may be retracted at up to 235 KIAS and extended at up to 265 KIAS, and VLE, the maximum speed with the gear down, is also 265 KIAS. The E190-E2 has lower operating speeds, 220 KIAS for retraction and 250 KIAS for extension, with the same VLE of 265 KIAS. The E190 E1 tyre speed limit is 195 kt ground speed.
How far can the E190-E2 nosewheel turn?
The rudder pedals steer the nosewheel up to 7 degrees either way. The hand wheel gives up to 76 degrees at 10 kt or less, reducing, though not in proportion to speed, to 20 degrees at 26 kt and 7 degrees above 100 kt. If the steering is disengaged or faulty, or the nosewheel is turned beyond 76 degrees, it castors freely up to 170 degrees either way, and the crew steer with differential braking and rudder.
When does the E190 LDG GEAR warning sound?
With flaps 0 to 4 and the gear not down, it sounds below 700 ft radio altitude when one thrust lever is below a set angle: 38 degrees with all engines operating or 57 degrees with one inoperative on the E190 E1, and 45 and 60 degrees on the E190-E2. On the E190 E1 with flaps 5 or full it sounds whatever the thrust and cannot be silenced.
Test yourself on Embraer E-Jet Landing Gear, Brakes and Steering
The v1prep banks cover this topic in the E-Jet type-rating bank, with a worked explanation for every answer. EASA ATPL, PPL, IR and CPL, the FAA written tests and type ratings for the A320, 737, A220, 787, ATR 72 and E-Jet.
Start practising →Sources and further reading
- EASA Type-Certificate Data Sheet EASA.IM.A.071, Embraer ERJ 190 (ERJ 190-100, -200, -300 and -400)
- EASA Easy Access Rules for Large Aeroplanes (CS-25), CS 25.729 Retracting mechanism and CS 25.735 Brakes and braking systems
- 14 CFR 25.729, Retracting mechanism (position indicator and warning device)
- 14 CFR 25.735, Brakes and braking systems
- FAA Aviation Maintenance Technician Handbook, Airframe (FAA-H-8083-31B), Chapter 13, Aircraft Landing Gear Systems
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.