Seattle, Washington - Boeing conducted some test flights with a Boeing 737 MAX 7 over the Pacific on August 5 and 6 to test the aircraft's troubled stall prevention system known as MCAS.
In the early morning of August 5th, the first 737 MAX 7 prototype ever built with registration N7201S took off from Renton for a test flight. The manufacturer, among other things, tested the updated anti-stall system produced exclusively for the 737 MAX Series jets
Flight BOE0001 headed southwest coast of the Pacific and carried out a series of slow-flight maneuvers, including pitch-up, between 9,000 and14,000 feet.
The aircraft reduced its speed below 200 knots and then dived for a short time. After stabilizing the aircraft and climbing to the previous altitude, the maneuver started again. The test was repeated at least seven times.
The overlay of August 5 Flight Copyright Flightaware.com
The flight lasted three hours and 10 minutes.
The slow-flight maneuvers were intended most likely to test the aircraft's notorious stall-prevention system known as MCAS (Maneuvering Characteristics Augmentation System).
The aircraft took off one more time the next day (August 6). This time it headed toward the west over the Pacific and repeated similar maneuvers there like the day before.
The overlay of August 6 Flight Copyright Flightaware.com
This flight took a little bit longer compared to the previous day's flight: 3 hours and 56 minutes.
The 737 MAX 7 is the smallest variant of the MAX Series and the most vulnerable one to a stall situation due to its shorter fuselage and heavier engines.
The 737 MAXs have been globally grounded since March 13 after the second deadly 737 MAX 8 crash on March 10, this time in Ethiopia. The first accident happened on October 29 in Indonesia. 346 people in total were killed in both accidents.
The investigations revealed the anti-stall software (MCAS) of the aircraft played a critical role in both crashes.
Also Read: How the Boeing MCAS System Really Works
Boeing has been working on some software fixes since then in the 737 MAXs flight-control systems and is expected to submit these fixes to the U.S Federal Aviation Agency for review in a few weeks.