When the pilots of the defunct Boeing jets in Ethiopia and Indonesia fought to control their aircraft, they lacked two notable safety features in their cockpits.
One reason: Boeing charged extra for her.
For Boeing and other aircraft manufacturers, the practice of charging to upgrade a standard aircraft can be lucrative. Top airlines around the world have to pay well to get the ordered jets equipped with tailored add-ons.
Sometimes these optional features combine with aesthetics or comfort, such as first-rate seating, extravagant lighting or additional bathrooms. Other functions include communications, navigation or security systems and are essential to the operation of the aircraft.
After the two deadly crashes of the same jet model, Boeing will make one of these safety features the standard to get the airplanes back in the air.
It has not happened yet Did you know what the crashes of Ethiopian Airlines Flight 302 on March 10 and Lion Air Flight 610 had caused five months earlier, both after unsteady launches. Investigators are however investigating whether a new software system added to avoid congestion in the Boeing 737 Max series may have been partly to blame. Incorrect data from sensors in the Lion Air aircraft could have caused malfunction of the system known as MCAS. The competent authorities investigate the crash suspect.
This software system measures two vanelike devices, known as angle-angle sensors. The nose of the aircraft points up or down in relation to the oncoming air. If MCAS detects that the aircraft is pointing upwards at a dangerous angle, it may automatically depress the nose of the aircraft to prevent the aircraft from stalling.
Boeing's optional safety features could have helped pilots partially Detect faulty readings. One of the optional upgrades, the Angle Display, shows the readings from both sensors. The other, called the non-consenting light, is activated when these sensors do not match.
Boeing will soon be updating the MCAS software and also setting the new undisputed light standard on all new 737 Max aircraft familiar with the changes that were made under the condition of anonymity because they were not published. The Attack Indicator will remain an option that airlines can buy.
None of the features was mandated by the Federal Aviation Administration. All 737 Max jets were grounded.
"They are critical and cost the airlines almost nothing," said Bjorn Fehrm, an analyst with aerospace consultancy Leeham. "Boeing calculates for them because it works. But they are essential for safety. "
Earlier this week, Dennis A. Muilenburg, Boeing's Chief Executive, said the company is working to make the 737 Max safer.
" As part of our usual practice after an accident, we review the design and operation of aircraft and, where appropriate, introduce product updates to further enhance safety. "
Extra functions may be large sellers of aircraft manufacturers.
In 2013 By the time Boeing launched its 737 Max 8, one expected $ 800,000 to $ 2 million for various options for such a narrow-bodied aircraft, according to a report by Jackson Square Aviation, a consultancy in San Francisco, which is about 5 percent of the final price of the aircraft.
Boeing calculates, for example, an additional fire extinguisher in the hold. Incidents in the past have shown that a single fire extinguisher in the hold Extinguishing system may not be sufficient to extinguish flames that spread quickly in the aircraft. Regulators in Japan require airlines to install backup fire extinguishing systems that F.A.A.
"There are so many things that should not be optional, and many airlines want the cheapest plane you can get," said Mark H. Goodrich, an aviation lawyer and former technical test pilot. "And Boeing can say," Hey, it was available. However, what Boeing does not say, he added, is that it has become a "big profit center" for the manufacturer.
Both Boeing and its airline customers have sought these options and prices The airline often edits details of the features it chooses to exclude or excludes from its submissions to the financial regulators, and Boeing declined to provide the full menu of security features it considered options for The 737 Max offers or reveals their costs.
But an unadjusted 2003 filing for an earlier version of the 737 shows that Gol Airlines a The Brazilian airline paid $ 6,700 extra for its oxygen masks for its crew and $ 11,900 for a state-of-the-art weather radar control panel, Gol did not immediately respond to a request for comment.
three American airlines, who bought the 737 Max, tracked the cockpits differently.
American Airlines, which ordered 100 of the aircraft and had 24 aircraft The fleet bought both the pitch indicator and the mismatched light, the company said.
Southwest Airlines, which has ordered 280 of the aircraft and counts 36 in its fleet, had already purchased the "disagree" option. An indicator for the angle of attack was installed on a display above the pilots' heads. After the Lion Air crash, Southwest said it would change its 737 Max fleet to place the pitch indication on the pilots' main screens.
United Airlines, which ordered 137 of the aircraft and got 14, did not pick the ads or the other light. A spokesman for the United States said the airline did not include the functions because its pilots had used other data for the flight.
Boeing makes further changes to the MCAS software.
When it was introduced, MCAS only took measurements from the sensor on a particular flight, making the system vulnerable to a single point of failure. One theory of the Lion Air crash is that MCAS has received faulty data from one of the sensors, resulting in a non-recoverable dive.
The software update, which Boeing expects to see soon, is being modified to read from both sensors. If there are significant disagreements between the measurements, MCAS will be disabled.
Incorporating mismatched light and angles of attack on all aircraft would be a welcome step, safety experts said, alerting pilots – and maintenance staff using aircraft after a problematic flight – problems with the sensors.
In particular, the warning would alert people to a sensor malfunction and alert pilots that they should prepare to shut down the MCAS if they mistakenly activated it, said Peter Lemme, avionics and satellite communications consultant and former Boeing flight control engineer ,
"In the heat of the moment it would certainly help," he said.