Bad times just got worse for Boeing after transcripts of alarmed messages between Boeing technical pilots sent three years ago surfaced publicly this week. The aerospace giant is presently in the middle of attempts to re-certify the deadly 737-MAX with regulators for commercial flight, but it will now find itself in the midst of another battle after NPR received a transcript of pilots warning that the "MCAS" system, which has been at the centre of blame, was "sending the plane all over the place" in simulator tests years before the two perilous crashes. If only someone at the time let the regulators know... What Is MCAS? MCAS is a 737-MAX flight stabilization system at the centre of ongoing investigations into how the plane was ever certified by regulators, partly because a decision was made not to inform pilots about it, or put it into training manuals. That's right - the system, arguably the greatest contributing factor to the perilous fate of those two planes, which killed 345 souls was never disclosed to pilots. They quite literally did not know it existed. The MCAS system was designed to act whenever a sensor detected that the plane was in danger of a stall, and was intended as a safety feature to keep pilots from flying at unsafe angles. Unfortunately, the singular sensor which controlled the system was flawed, and because of the inaccurate "angle of attack" reading, it was aggressively pushing the plane down. In both crashes, pilots fought tirelessly to stabilize, but the ill fated MCAS system won each time. It's hard to imagine. What Did Boeing Withhold? To make matters worse, months ago Boeing turned over 1,000's of pages of documents to a US House Of Representatives inquiry, but chose to leave out a crucial exchange between pilots, in which they explicitly raised concerns about the MCAS system. These weren't just any pilots, but rather the Chief 737 Technical Pilot for Boeing at the time, and another technical pilot. "Somehow they saw fit, even though they've had it four months, not to provide us this document, which in my mind is the smoking gun," - CongressmanPeter DeFazio told NPR. The pilots concerns were raised three years ago, and at the time the pilots claimed Boeing engineers and test pilots were aware of the flaws but efforts to fix them were ambiguous at best. Unfortunately, it seems no one acted, and allegations have been made that financial pressure on the program from the business end was a factor. Boeing needed to maximize profits. Unfortunately, the pilots in question continued to tell regulators that it was unnecessary to put the MCAS system into airline pilot manuals, but many people see these revelations as Boeing attempting to create a lone wolf theory, and distance itself from blame. Sure, the pilots should have spoken up more to regulators, but if flaws were reported to Boeing by the very team they hired to find them, why weren't they addressed? The conversation is available to read in full on NPR, but some of the more notable quotes are quite upsetting. "I'm levelling off at 4,000 feet, 230 knots and the plane is trimming itself like crazy, I'm like what?!" "MCAS is now active down to M.02 and it's running rampant in the SIM on me" "Why are we only just hearing about this" "I dunno, the test pilots are keeping us out of the loop" "They're all so damn busy, and getting pressure from the program" 737 MAX Re-Entry Into Service Both the FAA and house transportation committee offered scathing responses to NPR in light of the new revelations, but they might not make any difference in the plane re-entering the skies. American, United, Southwest and other operators have pushed re-entry dates back into 2020, after a previously expected Q4 2019. Most airlines now target a January 16th, 2020 date for return of the aircraft to fleets around the world. If you're booking flights after this date, be sure to look at the aircraft type being offered. The plane will likely be one of the safety machines ever to take to the skies upon its return, but that does not necessarily mean many travellers will want to fly on it.