VIVAERO

TAP Air Portugal's Airbus A330neo draws attention for flames coming out of the engine during start-up

The start-up of an engine on a TAP Air Portugal Airbus A330neo caught the attention of the internet after large flames were seen coming out of the engine's exhaust.

The A330-900neo jet, equipped with Rolls-Royce Trent 7000 engines, was starting up at Porto Airport in Portugal on a cold winter morning last week. The SpotterPorto channel recorded the moment the engine was started, with condensation vapor coming out of the rear of the engine, followed by a large flame.

Although the images are striking, this situation is neither uncommon nor dangerous, being simply an accumulation of fuel in the combustion chamber, this reaction having been caused by a delay in ignition, common in the first start of the day. The principle is the same used in sports cars that have modifications to the engine control to generate the so-called "Pop's and Bangs" in the automotive world.

"Pops and bangs" (pops and small explosions in the exhaust) are a common phenomenon in tuned or high-performance cars, but they are not a normal or desirable characteristic in aircraft engines. In aircraft, "pops and bangs" sounds in the engines usually indicate a serious problem, such as a compressor stall.

In Cars...In the automotive context, "pops and bangs" are characteristic sounds that occur in the exhaust system, usually during deceleration or gear changes. They are caused by incomplete combustion of fuel in the exhaust. Many sports car enthusiasts consider these sounds desirable and often modify the Electronic Control Unit (ECU) software to maximize this effect.

In Aircraft...In aircraft engines (especially jet engines), a "pops and bangs" sound is a symptom of an airflow problem called compressor stall or compressor surge.

What it is: It occurs when the airflow through the engine compressor is interrupted or becomes unstable, often due to damage to the blades (for example, from a bird strike or bird ingestion), severe atmospheric conditions, or mechanical failures.

The sound: Compressor stall produces a series of knocking or exploding sounds (similar to "pops and bangs") in a staccato pattern, which can be quite loud and noticeable in the cabin.

Consequence: Although modern jet engines are designed to withstand such events and generally do not fail immediately, a compressor stall is an emergency situation that requires reduced engine power and, in most cases, an emergency landing for repairs.

Therefore, while "pops and bangs" in cars are often an intentional customization feature, in airplanes they are a sign of an abnormal and potentially dangerous operating condition.

by Vivaero