Why Does The Airbus A340 Have Four Small Engines Instead Of Two Bigger Ones?

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Passengers connected Airbus jets operated by U.S.-based discount airlines for illustration Frontier and Spirit whitethorn have a bad experience that feels for illustration riding on, well, an existent bus. With difficult integrative seats and legroom champion suited for children, it's an unpleasant measurement to travel. But backmost successful nan precocious 1970s, erstwhile films for illustration "Saturday Night Fever" graced nan large screen, Airbus was itching to bring nan conflict complete prestigious long-haul power to much established aerospace companies for illustration Boeing and McDonnell Douglas. 

The 2 widebody jets that emerged from that improvement process successful nan early 1990s were Airbus' A330 and A340, which are rather similar, sharing nan aforesaid fuselage, formation deck, and helping design. As a result, pilots and unit tin move betwixt them with small further training. However, 1 important favoritism is that nan A340 has 4 smaller engines compared to nan A330's 2 larger ones. 

The main logic for offering nan A340 pinch its quartet of engines was that immoderate hose customers preferred nan redundancy of having 4 engines successful nan arena of an motor nonaccomplishment while flying agelong routes complete unfastened oceans. American carriers were comfortable pinch 2 engines, but Asian airlines operating crossed nan Pacific preferred four. However, since nan A340 debuted, twin-engine jets are progressively being certified for flying longer distances without a backup airdrome nearby. That detracts from nan request for nan A340 pinch its higher operating costs. Of nan 377 full A340s built, only 49 run successful regularly scheduled rider work arsenic of May 2025.

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The decease knell for nan A340's fame came successful nan shape of ever-increasing ETOPS ratings for twin-engine jets. ETOPS is short for Extended-Range Twin Operations Performance Standards, though it's besides been joked that nan acronym stands for "Engines Turn Or Passengers Swim." Basically, ETOPS determines really acold distant twin-engine craft tin stray from contingency airports successful lawsuit 1 motor fails. For example, nan Airbus A350 has an ETOPS standing of 370, which intends that it tin proceed flying for 370 minutes to information utilizing conscionable 1 engine. That's importantly longer than nan first ETOPS standing of conscionable 120 minutes, granted to a United Airlines Boeing 767 in nan 1980s while nan A340 was successful development.

Before ETOPS became a thing, copy motor jets were only allowed to alert paths that continually placed them 60 minutes aliases little from nan nearest airport, successful lawsuit they needed to divert. To circumvent nan 60-minute rule, craft manufactures turned to trijets (three engines) for illustration Douglas' DC-10 and moreover larger four-engine jets for illustration nan fuel-thirsty Boeing 747 and our subject, nan Airbus A340. Nowadays, relatively few jets pinch greater than 2 engines stay successful commercialized rider service, though immoderate are still celebrated for carrying cargo owed to their somewhat higher weight capacities.

As for why nan A340's engines are truthful diminutive, it's truthful nan 4 engines' fuel consumption and sound level weren't wholly noncompetitive pinch twinjet aircraft. That said, nan A340's substance system is still marginally worse, not to mention the costs of servicing, or replacing erstwhile necessary, 4 engines versus conscionable two.