The Aviation Herald already has an image of the Flight Data Recorder information from the crash of TransAsia GE235: TransAsia GE235 FDR plot (click to enlarge)

I have determined that the green lines are for engine 1 and the blue lines are for engine 2, but beyond that, I'm a bit lost. Can someone translate the abbreviations and describe what information each graph is indicating for non-pilots.

  • 1
    $\begingroup$ Looks like they shut down the wrong engine after #2 failed. $\endgroup$ Feb 6, 2015 at 18:22
  • $\begingroup$ Wow... that looks pretty damning. $\endgroup$
    – J...
    Feb 6, 2015 at 21:52
  • $\begingroup$ I took the liberty of editing the title: this is only a specific FDR plot, a full FDR plot contains hundreds of signals not displayed here. $\endgroup$
    – Federico
    Feb 7, 2015 at 15:23
  • 2
    $\begingroup$ here's an annotated description of the FDR by an ATR captain: reddit.com/r/aviation/comments/2uyy3n/… $\endgroup$
    – rbp
    Feb 7, 2015 at 15:36

2 Answers 2


From top to bottom:

  • main gear : whether there is weight-on-wheel not [scale on the left, in blue: "air/gnd"] (thanks to DeltaLima for pointing this out)
  • VHF1 : probably if there was communication of that radio channel (speculation on my side) [no scale]
  • Master warning : if the MW signal for engine flame out was active or not [scale on the right, in green : "fault/-"]
  • CLA : Conditioner Lever Angle [scale on the right, in green : "fuel SO/no FSO"]
  • Beta : usually is used to indicate aircraft sideslip, in this case is referring to the propeller blades, 90 degrees signal feathering. [scale on the left, in green : "90//10"]
  • Bleed valve : whether it was open or closed (as labeled on the right) [scale on the right, in green : "open/closed"]
  • PLA : power lever angle, aka throttle lever position [scale on the left, in green : "80//30"]
  • ITT : inter turbine temperature [scale on the right, in green : "700//100"]
  • NP : propeller RPMs as % of max RPMs [scale on the left, in green : "100//0"]
  • Fuel flow [scale on the right, in green: "2000//0"]
  • Objective TQ: objective torque (*) [scale on the right, in green : "100//80"]
  • TQ : torque [scale on the right, in green : "200//0"]
  • NL : low pressure shaft RPMs [scale on the left, in green : "100//0"]
  • NH : high pressure shaft RPMs [scale on the right, in green : "100//0"]
  • Oil pressure [scale on the right, in green : "100//0"]
  • Barometric corrected altitude [scale on the left, in cyan: "2000//0"]

*: from page 2 of that link: enter image description here

  • $\begingroup$ Federico, I think Main Gear A/G does not reflect the state of retraction, but rather the state of the weight-on-wheels switch. $\endgroup$
    – DeltaLima
    Feb 8, 2015 at 10:08
  • $\begingroup$ @DeltaLima you might be right, comparing to the adjusted altitude your explanation makes more sense than mine. Thanks! $\endgroup$
    – Federico
    Feb 8, 2015 at 12:51

Main Gear (A/G) is the signal of air/ground detecting solenoid that is in the main gear strut AFAIK, it detects when the aircraft is airborne and actuates several different systems that have different behavior while in flight than while on ground.

It is not Gear UP/DOWN condition, in most FDRs gear position are 3 different signals one for each gear.


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