Tag | Variable | Remarks |
---|---|---|
100 | Time | The T-28 data system is always set to universal time, and recorded in a 24-hour format. It is maintained daily within a second of WWV unless otherwise noted. |
101 | Dynamic Pressure 1 | |
102 | Dynamic Pressure 2 | Both dynamic pressures are read from the same pitot tube line (with the inlet out on the right wing) using two different but nearly identical sensors. [hPa] |
103 | Static Pressure 1 | |
104 | Static Pressure 2 | Both static pressures are read from the same static pressure line (inlet on the rear fuselage) using two different but nearly identical sensors. [hPa] |
105 | Rate of Climb | The instantaneous rate of change of aircraft altitude, read from a standard aircraft variometer. The recorded data are unfiltered and much noisier than the damped cockpit display. [m s^{-1}] |
106 | Rosemount Temperature | This is static temperature computed from the reading of a standard, deiced, Rosemount aircraft total air temperature probe. It commonly suffers from wetting and reads low in clouds. [°C] |
107 | Reverse Flow Temperature | This is static temperature computed from the reading of a platinum resistance element placed inside a custom-design "reverse-flow" housing.It normallydoes not get wetincold clouds or in regions of high precipitation water concentration. Apparently, ice may sometimes build up to such an extent on the housing that temperature readings are affected even though the sensor is not wetted. Its response to changes in angle of attack is greater than that of the Rosemount probe. [°C] |
108 | Manifold Pressure | Pressure inside the engine manifold (an indicator of power being developed by the engine) is recorded from a standard aircraft engine presssure sensor. [inches of mercury] |
109 | Acceleration | Vertical acceleration is determined by a Humphrey gyro-stabilized accelerometer. [g’s] |
110 | Pitch | The accelerometer also gives angle of the fuselage relative to horizontal (positive for nose up). [deg] |
111 | Roll | Finally, the accelerometer gives angle of the wings relative to horizontal. Angle is positive for a left bank (left wing down). [deg] |
113 | VOR | The VOR gives the direction to the VORTAC (a radio direction-finding beacon used by aircraft) to which it is tuned. [deg] |
114 | DME1 | This is distance to the VORTAC to which the DME is tuned. [n mi] |
116 | Voltage Regulator | Voltage of power source for some instruments. [volts] |
117 | Heading | Indicates direction (from magnetic north) towards which the aircraft is heading. [deg] |
118 | NCAR True Airspeed | Airspeed computed by an analog circuit; can be used to clock PMS OAP-2D probes. Less accurate than "Calculated TAS", Tag 211 |
119 | PMS End Element 1 | Voltage readings of PMS OAP-2D probe end diodes. Used to monitor for fogging and icing of probe. |
120 | PMS End Element 2 | |
121 | Interior Temperature | Temperature inside the data acquisition system computer in the baggage bay. [°C] |
124 | Heater Current | Total current consumed by de-icing circuits (A). |
130 | Event Bits | Bits corresponding to various events recognized by the data system, including an indication that the system is running, that the in-cloud switch is activated by the pilot (when visually entering cloud), that the foil impactor is running, and that the cockpit voice recorder is activated. |
131 | GPS Warning Codes | Bits corresponding to various status messages from the GPS system. |
140 | FSSP size counts | This tag contains information concerning the number of counts in each of the 15 available FSSP size channels. [number per channel per second] |
141 | FSSP total counts | The total number of droplets counted by the FSSP during a second. |
142 | FSSP average diameter | The arithmetic average diameter of all droplets recorded during a second. [m m] |
143 | FSSP concentration | The actual concentration of droplets computed from FSSP counts divided by the volume sampled in 1 s ("Standard method"). A rudimentary correction for probe activity is made. [# cm^{-3}] |
144 | FSSP Water | The liquid water concentration computed from the FSSP data for a second ("Standard method"). [g m^{-3}] |
145 | FSSP Activity | The fraction of time the FSSP is active during the current second. |
147 | PMS 2DC Shadow Or Count | The number of times the 2D probe was triggered out of its wait state by the passage of a new particle. [# s^{-1}] |
148 | FSSP Equivalent Diameter |
at one second intervals, using "standard method" counts and sizes. |
149 | Variance in FSSP Equivalent Diameter | Variance
around the equivalent diameter, computed as
using "standard method" counts and sizes. |
150 | Hail size counts | This tag contains information on the number of particles in each of the 14 hail spectrometer size channels. [number per channel per second] |
151 | Slow Particle | The number of particles rejected because they passed through the hail spectrometer too slowly (indicating they were probably water or ice shed from the probe structure rather than airborne hydrometeors). [number per second] |
152 | Hail total counts of (150) | Total number of particles accepted by the hail spectrometer. [number per second] |
153 | Hail average diameter | The average diameter of all particles accepted by the hail spectrometer in the last second. [cm] |
154 | Hail concentration | The computed concentration corresponding to all particles accepted by the hail spectrometer in the last second. [number per cubic meter] |
155 | Hail Water | The mass concentration computed from the observed particle spectrum assuming spherical particles and a bulk particle density of 0.9 grams per cubic centimeter. [grams per cubic meter] |
160 | Top Field Mill | The electric field indicated by the low sensitivity channel on the field mill mounted in the aircraft canopy looking up. Field mill data are recorded at 20 Hz. [kV m^{-1}] |
161 | Bottom Field Mill | The electric field indicated by the low sensitivity channel on the field mill located in the baggage bay door looking down. [kV m^{-1}] |
162 | Left Field Mill | The electric field indicated by the low sensitivity channel on the field mill mounted in the left wing tip facing outward. [kV m^{-1}] |
163 | Right Field Mill | The electric field indicated by the low sensitivity channel on the field mill mounted in the right wing tip facing outward. [kV m^{-1}] |
168 | Fifth Field Mill | The electric field indicated by the low sensitivity channel on the fifth field mill, located forward in one of the hail spectrometer pylons under the left wing. [kV m^{-1}] |
169 | Sixth Field Mill | The electric field indicated by the low sensitivity channel on the 6^{th} field mill, located aft in the hail spectrometer pylon under the left wing (kC m^{-1}) |
172 | Latitude | Computed internally in the GPS receiver. [deg] |
173 | Longitude | Also computed internally in the GPS receiver. [deg] |
174 | Groundspeed | Computed internally in the GPS receiver (by differentiating the position data with respect to time). [m/s] |
175 | Ground Track Angle | The direction towards which the aircraft is moving relative to the ground, with respect to magnetic north. [deg] |
176 | Magnetic Deviation | The difference between magnetic north and true north as indicated automatically by the GPS receiver based on the current position. [deg] |
177 | Time Since Solution | The time since the GPS was last able to compute an accurate position solution based on a sufficient number of satellites. The GPS updates position based on dead reckoning if it does not have a sufficient number of satellites in view. [s] |
178 | GPS Altitude | Geometric aircraft altitude. [m MSL]] |
190 | FSSP Gated Strobes | Number of accepted droplet counts. [s^{-1}] |
191 | FSSP Total Strobes | Total number of droplet counts. [s^{-1}] |
192 | FSSP Reference Voltage | Reference voltage for FSSP opto-electronics. |
200 | Date | As indicated by the data acquisition system computer clock. [yymmdd] |
201 | Month | mm [integer number] |
202 | Day | dd [integer number] |
203 | Year | yy [integer number] |
204 | Flight | A serial number assigned to each T-28 flight beginning with the "first" research flight. (Flight #1 occurred in 1972.) |
205 | Altitude | The altitude in a standard atmosphere corresponding to the recorded static pressure. [m] |
206 | q_{e} | The equivalent potential temperature corresponding to the recorded temperature and assuming saturation with respect to liquid water (should be valid in-cloud). [K] |
207 | Saturation Mixing Ratio | The mixing ratio of water vapor corresponding to saturation with respect to liquid water at the recorded temperature. [g kg^{-1}] |
208 | Point dz/dt | The rate of change of altitude of the aircraft computed by differentiating the pressure altitude with respect to time. This represents an independent estimate of the rate of climb to be compared to tag 105. [m s^{-1}] |
209 | Indicated Air Speed | What the airspeed would be if the aircraft were flying at sea level and indicating the observed dynamic presure. [m s^{-1}] |
210 | Updraft (uncorrected) | The estimated upward speed of the air relative to the ground computed from changes in the aircraft altitude and other factors, but not corrected for horizontal aircraft acceleration. [m s^{-1}] |
211 | Calculated TAS | The true speed of the aircraft relative to the air computed from the observed dynamic and static pressures, and temperature. [m s^{-1}] |
212 | Updraft Correction Factor | A correction to tag 210, the simple (uncorrected) updraft calculation, that accounts for horizontal accelerations of the aircraft. [m s^{-1}] |
213 | Cooper Updraft | The sum of the uncorrected updraft and the correction factor. [m s^{-1}] |
214 | Kopp Updraft | An updraft calculated somewhat differently than the Cooper updraft [Kopp, 1985]. In most situations, it yields a less noisy and more physically plausible updraft result for the T-28 than the Cooper method. [m s^{-1}] |
215 | Geopotential Altitude | Altitude computed from changes since takeoff in static pressure and temperature, using the hydrostatic equation. [Not routinely computed, but can be computed upon request.] [m] |
216 | Turbulence | The turbulent energy dissipation rate estimated from the spectrum of observed fluctuations in true airspeed following a method developed by McCready. [cm^{2/3} s^{-1}] |
217 | Air Density | Computed from the
recorded temperature and static pressure.
[kg m^{-3}] |
218 | J-W Mixing Ratio | The mixing ratio of cloud water per unit mass of dry air based on the J-W reading and computed air density. [g kg^{-1}] |
219 | FSSP Mixing Ratio | The mixing ratio of cloud water per unit mass of dry air calculated from the FSSP water concentration. [g kg^{-1}] |
220 | Hail Mixing Ratio | The mixing ratio of hail mass per unit mass of dry air based on the computed hail water and air density. [g kg^{-1}] |
244 | FSSP equivalent J-W Liquid Water | An estimate
of the liquid water
concentration the J-W probe should record, based on the observed FSSP droplet spectrum and the assumption that the J-W responds incompletely to droplets larger than 30 mm diameter. [g m^{-3}] |
260 | Ambient Vert Electric Field | The component of the ambient electric field that is vertical in the aircraft frame of reference. Positive means a positive test charge would drift upward relative to the aircraft in the field. [kV m^{-1}] |
261 | Vert Electric Field due to aircraft charge | The field due to charge on the aircraft, computed by summing the readings of the top and bottom mill and normalizing based on self-charging tests. Positive means a positive test charge would be repelled away from the aircraft due to its charge. [kV m^{-1}] |
262 | Ambient Hor Electric Field | The ambient field oriented perpendicular to the aircraft along the wings, positive meaning a positive test charge would drift to the right in the field. [kV m^{-1}] |
263 | Hor Electric Field due to aircraft charge | The field due to charge on the aircraft, computed by summing the wingtip mill readings and normalizing. Positive means a positive charge would be repelled away from the aircraft due to its charge. [kV m^{-1}] |
264 | Ambient Vert Field (roll cor) | The component of the ambient field that is truly vertical with respect to earth coordinates. [kV m^{-1}] |
265 | Ambient Hor Field (roll cor) | The component of the ambient field perpendicular to the aircraft path and truly horizontal with respect to earth coordinates. [kV m^{-1}] |
266 | Ex | X-component of ambient horizontal electric field, based on Mo et al (1999). Positive means a positive test charge would drift in the direction of the aircraft under the influence of the field. [kV m^{-1}] |
267 | Ey | Y-component of ambient horizontal electric field, based on Mo et al (1999). Positive means a positive test charge would drift to the right of the direction of the aircraft under the influence of the field. [kV m^{-1}] |
268 | Ez | Z-component of ambient electric filed, based on Mo et al (1999). Positive means a positive test charge would drift upward under the influence of the field. [kV m^{-1}] |
272 | Latitude (deg) | GPS coordinates broken into separate degree and minute components. |
273 | Latitude (min) | GPS coordinates broken into separate degree and minute components. |
274 | Longitude (deg) | GPS coordinates broken into separate degree and minute components. |
275 | Longitude (min) | GPS coordinates broken into separate degree and minute components. |
276 | Ground Track Angle (True N) | The direction of motion relative to the ground with respect to true north, derived from the GPS ground track angle with respect to magnetic north. |
290 | X-acceleration | Acceleration in the direction of aircraft motion. Acceleration backward (deceleration) yields a positive value. [g] |
291 | Y-acceleration | Acceleration perpendicular to the direction of aircraft motion, along the direction of the wings. Acceleration toward the left yields a positive value. [g] |
292 | Z-acceleration | Vertical acceleration. Upward acceleration produces a positive value. [g] |
[Tags 341 – 349 can be computed for upon request.] | ||
341 | Calculated FSSP Total Count | Observed
FSSP total counts with minor
corrections made in an attempt to correct for the effects of ice particles on FSSP droplet spectra. Not fully proven. [s^{-1}] |
342 | Calculated FSSP Average Diameter | FSSP average droplet diameter estimated from spectra calculated using the Baumgardner FSSP data reduction procedure. [m m] |
343 | Calculated FSSP Concentration | Droplet concentration estimated using the Baumgardner FSSP data reduction procedure. [# cm^{-3}] |
344 | Calculated FSSP Water | Liquid water concentration estimated using the Baumgardner FSSP data reduction procedure. [g m^{-3}] |
345 | Calculated FSSP Mixing Ratio | Computed from "calculated FSSP water" (tag 344) and "air density" (tag 217). [g kg^{-1}] |
348 | Calculated FSSP Equivalent Diameter | Computed as for tag 144, but using FSSP spectra derived using the Baumgardner FSSP data reduction procedure. [mm] |
349 | Variance of the Calculated FSSP Equivalent Diameter | Computed as for tag 149, but using FSSP spectra derived using the Baumgardner FSSP data reduction procedure. |