Boeing has admitted that it knew about a problem with its 737 Max jets a year before the aircraft was involved in two fatal accidents, but took no action.
Boeing said it had inadvertently made an alarm feature optional instead of standard, but insisted that this did not jeopardise flight safety.
You can read the full Boeing statement here
The feature at issue is known as the Angle of Attack (AOA) Disagree alert and was designed to let pilots know when two different sensors were reporting conflicting data.
Boeing said it had intended to provide the feature as standard, but did not realise until deliveries had begun that it was only available if airlines purchased an optional indicator.
It said it had intended to deal with the problem in a later software update.
Boeing maintained that the software problem “did not adversely impact airplane safety or operation”.
All 737 Max planes were grounded in March after an Ethiopian Airlines flight crashed, killing 157 people.
Five months earlier, 189 people were killed in a Lion Air crash.
The worldwide fleet of 737 Max planes was of 387 aircraft at the time of the grounding.