On this website there’s an audio fragment between the TBM900 and ATC.
The pilot requests a descent: “9KN we need to descent to FL180, we have an indication there’s something not correct with the plane”.
He got a clearance to descent to FL250, to which the pilot replied: “We need to get lower”.
From the next radio messages, it seemed that the pilot became hypoxic (he sounds sleepy), and loses conciousness pretty soon afterwards.
What could have saved him was a MAYDAY call, followed by a direct emergency descent…
Part 121 requires either a quick donning oxygen mask above FL250, or a crew member to wear a mask if one of the crew members leave the cockpit.
It seems a good suggestion for single pilot operations above FL250. Does the TBM have a quick donning system? Wouldn’t there be emergency oxygen as a matter of course. I can see why ATC would not have interpreted this as an emergency if it had not been declared, because they would have assumed if there was a pressurisation leak the crew would have donned oxygen, or declared an emergency and carried out an emergency descent.
The FAA is quite keen on demonstrating emergency descents: power to idle, gear down, 30 degree bank and speed to Vlo.
Surely this would have been a Part 91 flight, not Part 121?
I think Part 91 only requires oxygen to be available above 250 and the provisions you mention above above 350. Above 410 one pilot has to wear the mask all the time.
I agree with your comments though. This is another terribly sad event.
I wonder whether the antiquated warning systems employed in aircraft are a factor in these accidents. Bleeeeeeep and hooooonk are not that good compared to “warning – check gear!” Or “Cabin altitude – Descend! Descend!”. the G1000 has an annunciation when above 10,000ft or so and oxygen is off, but that is way too subtle when hypoxic.
Remember Helios – the same horn used for configuration warning and for cabin altitude.
the G1000 has an annunciation when above 10,000ft or so and oxygen is off, but that is way too subtle when hypoxic.
Depends on the installation. In the Meridian you get a yellow caution over 10k with a single chime. Over 12k you get a continuous chime and red warning CAS message. It also activates emergency bleed air into cabin. I would be really surprised if that TMB900 didn’t do something similar.
Besides that how do you perform an emergency descent. Until now I would fly it by hand but maybe it is better to do it on the autopilot, leave some throtle and dial in a target altitude at FL100 or FL80 depending on terrain. So in case you pass out the plane would take you to a save altitude without any pilot input and you have time to recover while the plane holds the altitude.
I would do it that way. Start the descent by hand but drop gear, flight idle then do an IAS descent to 10k feet. Of course only problem with that is that if you don’t wake up then the plane will stall when it levels.
Does the TMB900 (or any series) have emergency Ox and masks ? – at least for P1 or Is it an optional extra for public transport or standard ‘fit’?
It must have O2 for certification. The Meridian has a tank for the pilot and chemical O2 generators for passengers.
Interesting – seems that didn’t work either!!
Chemical O2 gen.. That’s something new to me. How does that work apart from by chemistry !?
If you depressurise is the O2 system ‘automatic’? or does the pilot have to get on it like PDQ (pretty damn quick)
