Why does the Boeing 777X not need MCAS similar to that of the 737 MAX?

Boeing made it clear in a retweet that its 777X does not feature MCAS similar to that of 737 MAX.

Boeing 777X
Boeing 777X has successfully completed its first test flight Photo: Boeing.

Boeing 777X has successfully completed its first test flight on Friday last week after many delays due to days of unfavourable weather.

However, this latest update of the triple seven does not feature MCAS similar to that of the troubled 737 MAX series.

Boeing 777X is the latest update of its best selling 777 series, which first flew back in 1994. This new project is already behind schedule, following several technical problems.

The significant structural difference in the latest 777X is a whole new wing with folding wingtips so that the plane can fit in all current airport gates.

Boeing 777X
Boeing 777X first test flight lasted for four hours Photo: Boeing.

So, the 777 does not have the same amount of modification between the older and recently updated variants. But there was a drastic change between the older 737 variants to the MAX ones.

Why has Boeing implemented MCAS in the 737 MAX?

MCAS was implemented in the 737 MAX, citing the considerable modification to the 737, combined with a strong desire to retain the original certification and only change the looks of the older design. But the 777 does not have similar modifications.

The 737 MAX uses the same fuselage, landing gear, same wing with a new set of winglets and aerodynamics, same tail fin and stabilisers and many other similar features, but more unique, more powerful and heavier engines.

The job of MCAS is to make the latest 737 MAX aircraft fly like a regular 737 variant from the pilot point of view. It means pilots can fly the MAX without extra simulator training.

Boeing 737 MAX
Boeing 737 MAX could return earlier than midyear Photo: Boeing

This software was found to be the leading cause behind the two deadly crashes last year, killing a total of 346 people on board. 737 MAX aircraft have been grounded since March 2019.

However, recently FAA stated that it was impressed with the improvements made by Boeing to get its grounded aircraft safely returned back into service.

Related topic: Boeing 737 MAX Could Return Earlier than Midyear

What makes the 777 safe without MCAS?

The 777 was initially designed back in the 90s as a fly-by-wire aircraft and has full-time fly-by-wire flight controls, with computers involved in each control input.

This means that the task MCAS was meant to apply to the 737 MAX is already built in the 777 aeroplanes as a part of its initial control rules.

Boeing 777X being presented at Seattle Photo: Boeing

Opposite to the re-engined 737 MAX, there’s very little difference in the design of the aircraft and the location of the engine is not changed even.

Boeing 777X has much longer landing gear with plenty of clearance between the wingtips and the engine to fit the new large engines well under the recently modified wing. This clearance gap pulls the aeroplane in a standard, neutral manner, which does not require additional electromechanical support like the MCAS to make it feel usual to the pilots.

Therefore, having no drastic differences between the latest Boeing 777X and initial 777s, there is no need to create an artificial feel through software like the 737 MAX. 

When will the 777X start its operation?

Dubai-based Emirates Airline is due to receive its first 777X, being the launch customer as stated earlier. Emirates is also the most significant 777 operator and has the most number of orders for the 777X.

As of now, Boeing has firm orders for a total of 309 aircraft from nine customers. The majority of the orders are from middle-east carriers. Each aircraft is worth more than $442 million at list price.

Emirates will be the launch customer for 777X Photo: Boeing.

The 777X will directly compete with the Airbus A350-1000, which seats about 360 passengers. Both aircraft competed for head to head to win orders from Qantas for its Project Sunrise flights last year. Eventually, Qantas opted for the Airbus A350 over the 777X, citing delays in the programme.

Do will think Boeing 777X will be a massive turnover to Boeing’s fame? Let us know in the comments below… 

(By Sharad Ranabhat)

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