A 320 Class

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What are ETOPS & ETP in Flight Planning?

Modern commercial aviation frequently involves long-range flights over oceans, deserts, and remote regions where suitable diversion airports are limited. To ensure safety during such operations, regulatory frameworks and operational planning concepts have been developed. Two important terms in this context are ETOPS (Extended-range Twin-engine Operational Performance Standards) and ETP (Equal Time Point). Although they are related to long-range operations, they serve different purposes and are often misunderstood.

ETOPS (Extended-range Twin-engine Operational Performance Standards)

ETOPS is a set of regulatory standards governing the operation of twin-engine aircraft on routes where the aircraft may be more than a specified flying time from an adequate diversion airport, following an engine failure or other critical system failure.

Purpose of ETOPS

- Ensure safe operation of twin-engine aircraft on long routes
- Address engine failure and system redundancy
-Standardize aircraft certification, maintenance, and crew training
- Enable efficient routing over oceans and remote regions

ETOPS Time Limits

It represents the maximum allowable single-engine flying time to a suitable alternate airport under defined conditions
- ETOPS-120
- ETOPS-180
- ETOPS-330

ETP (Equal Time Point)

The Equal Time Point (ETP) is a specific geographical point along a flight route where the time required to continue to the destination is equal to the time required to divert to an alternate airport.

Purpose of ETP

- Helps determine best course of action during abnormalities
- Used for engine failure, medical emergencies and pressurization failure
- Critical for long oceanic and polar routes

Types of ETP

- Critical ETP - Based on engine-out performance
- Medical ETP - Based on normal cruise speed
- Pressurization ETP - Based on depressurized cruise or drift-down speed

ETP Calculation Factors
- Distance between alternates
- Aircraft ground speed (wind corrected)
- Aircraft configuration ( Engine-out or Depressurized)
- Weather and operational constraints

Relationship between ETOPS and ETP

ETOPS defines how far an aircraft is allowed to operate from an alternate airport, ETP helps determine what action to take during a flight when an abnormal situation occurs. On ETOPS routes, ETP calculations are especially critical because diversion options are limited and time-critical.

The ELAC (Elevator and aileron computer) as the name suggests, control the elevators and the ailerons. There are two ELACs in the Airbus A320. ELAC 1 and ELAC 2. In normal operations, ELAC 1 primarily controls the ailerons and ELAC 2 controls the elevator and the horizontal stabiliser. In flight, these two computers are inter changeable. That is, if for example ELAC 1 were to fail, the aileron control is transferred to ELAC 2. The aileron control transfer is fairly straight forward and simple. However, this is not the case when transferring elevator controls.
The ELAC 2 controls the left and the right elevator surfaces through the yellow and the green hydraulic system. If ELAC 2 fails, the elevator control is passed onto the ELAC 1 which controls the elevator through the blue hydraulic system. Unlike ELAC 2 there is not two hydraulic systems assisting ELAC 1, but one system which is the blue hydraulic circuit. If the aircraft is dispatched with ELAC 2 inoperative, the ELAC 1 controls the elevator through the blue system. If the blue system fails, ELAC 1 cannot transfer control to other computers such as SEC (Spoiler elevator computer). ELAC 1, unlike ELAC 2 does not transfer elevator control to the SECs in a hydraulic failure.
Elevator and THS control of the A320.
Moreover, ELAC 2 is very critical if the aircraft were to go into an emergency electrical configuration, where the RAT (Ram air turbine) extends and powers an emergency generator which powers the blue hydraulic system. If you do not have a functioning ELAC 2 and ELAC 1 is only available, you might lose elevator control until the RAT fires up and start running the generator. The RAT extension takes a bit of time and losing pitch control even for a few seconds can be catastrophic.
Why is it not allowed to dispatch an Airbus A320 with an inoperative ELAC 2?
In case of loss of both the generators in flight, power supply to the primary flight computers ELAC1, ELAC2, SEC1 and SEC2 is disrupted (SEC3 is supplied but it does not have a pitch channel). The green and yellow hydraulic systems are still pressurised since the engine driven pumps are operative but the blue system is temporarily lost.
Hence, before the RAT (Ram Air Turbine) extends for about 8 seconds,
ELAC1 and SEC1 are powered by battery 1 and ELAC2 and THS motor 1 are supplied by battery 2.
This enables the ELAC2 to control both the elevators with the green and yellow servocontrols while the THS is operated with the motor 1 controlled by ELAC 2 again.
(ELAC1 can not control the elevators since blue hydraulic pressure is not available neither can SEC1 or SEC2 for similar reasons.)
With gear extension or possibility of a RAT stall, pitch authority is still retained by ELAC2 which makes it an absolute no go item.

In flight control sysThere are 2 ELAC 1&2, Why ELAC 2 is no go item ????

A 320 ✈️ ✈️ ATA 100 INDEX

Airbus has issued urgent safety instructions after discovering that intense solar radiation can corrupt flight-control data on A320 Family jets.

The manufacturer says the vulnerability could affect around 6,000 aircraft worldwide, according to AIRLIVE, prompting immediate precautionary steps.

Airlines have been told to install updated software or hardware protections under an Alert Operators Transmission, with EASA expected to issue an Emergency Airworthiness Directive.

The move may cause short-term flight disruptions as carriers apply the fixes.

Airbus apologised for the impact on passengers and stressed that safety is the priority as the global fleet undergoes rapid compliance checks.

Green light means the fuel quantity selected from cockpit ...
When light is off means refueling also completed.