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Capt. Brad Alberts MD11 Captain

Precision Vertical Navigation on the MD11/MD10 : PROFILE. V/S • PROF • IDLE • HOLD. Capt. Brad Alberts MD11 Captain. Disclaimer .

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Capt. Brad Alberts MD11 Captain

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  1. Precision Vertical Navigation on the MD11/MD10 : PROFILE V/S • PROF • IDLE • HOLD Capt. Brad Alberts MD11 Captain

  2. Disclaimer • This slide show is an attempt to more adequately explain precision vertical navigation on the MD11/MD10, know as PROFILE. It is a work-in-progress at this point in time. • Please confirm all information herein against CFM or other official FedEx/Boeing/Honeywell documents. • Make the aircraft do what you want it to do and fly safe! • I can be reached for questions at: jbalberts13@yahoo.com

  3. CFIT:Controlled Flight Into Terrain • Leading cause of hull loss around the planet • Most preventable through solid procedures • Requires all levels of protection to breakdown • Precision Vertical Navigation Systems (PROF) can assist in preventing it • if used properly in the approach environment!

  4. Review: Flying Tiger Flt 66Arrival KUL • Non-Precision/Automated Non-VNAV aircraft • ATC Cleared descent to 2,400’ • “Descend two four zero zero” • Crew heard, read-back & entered 400’! • Descend to “four zero zero” • Min segment altitude 2,400’ • Aircraft descended and crashed into side of mountain descending to 400’

  5. CFIT Levels of Prevention • Crew Situational Awareness (S/A) • Where are we & what’s below us? • PROFILE/VNAV (V/S • PROF • IDLE • HOLD) • Using Vertical Navigation (VNAV or PROF) • ATC Terrain Warning System • Most 1st World Countries only! • EGPWS Activation & Escape • Bottom layer of protection

  6. Definitions • Calculated Vertical Descent Path (CVDP): • The FMS calculated descent path that optimizes speed, fuel & DOC saving with path angle stabilization in compliance with MCDU distance, constraints & winds. Touching PROF enters autoflight into management of this profile. It is calculated without regard to how descent is actually flown. • Top of Descent Point (TOD): • FMS calculated Top of Descent point based on mileage (magenta line), speed & altitude constraints &winds aloft entry in PERF page • PROF: • FMA display when aircraft is operating ON the CVDP path (when profile management is activated after touching the PROF tile) • V/S: • FMA display when aircraft is below the CVDP or the pilot has started descent prior to calculated TOD using Vertical Speed (V/S) followed by pushing PROF • IDLE: • FMA display when aircraft is above the CVDP • HOLD: • FMA display when aircraft is in level altitude capture mode

  7. PROF System Architecture • Series of “IF > THEN” logic-flow statements • Next “thing to do” is conditional on something occurring and triggering it • New altitude, airspeed, config change • Change limited to programmed options • Limited pilot knowledge of how automation works leads to “the airplane is all #@$!%! up!” & using LVL CHG instead when PROF doesn't go as anticipated due to limited knowledge

  8. PROF Design Considerations • FAA Violations: 93 to 1 • 93 Altitude violations for each Speed violation • Aircraft alerts you to altitude errors as follows: • Altitude errors are annunciated on MCDU scratch pad • Arrows on ND also display altitude reached past required fix • High & long information displayed on the PERF page • System designed to comply with the crossing altitude restriction before speed compliance • System ‘advises’ pilot of inability to maintain speed • Flashing FMA above at selected Speed +10 KIAS • ADD DRAG advisory in ND

  9. Design of PROF: “IF>THEN” Conditional Statements • NADP 1 Push PROF to begin sequence: 400’ AGL-PROF PRE-PROGRAMMED TO: Speed MaintainsV2-V2+10 Flex/Max PWR A different logic-flow tree PRE-PROGRAMMED TO: At Anytime: CONDITION TO MEET: Confirm E/O? Speed MaintainsV2-V2+10 Flex/Max PWR 1,000’ AGL CONDITION TO MEET: Reaching EO Accel Alt Climb Power Accelerate to 250 KIAS 3,000’ AGL Reaching FCP Speed-250 Accel - 250 KIAS VFR& VSR prompts Climb to FCP Altitude 10,000’ MSL Reaching FCP Altitude Accel to 330 KIAS/.84 Await further pilot inputs

  10. Unintended Consequences of Level Change & V/S (Non-PROF/White FMA Indication) • Dive & Drive mentality of the non VNAV aircraft • Thinking that PROF “does not work” • Descends to FCP Altitude or hits the ground… whichever come FIRST! FMA Indication t NAV1 IDLE CLAMP 400’ THRUST 250

  11. Creating Accurate TOD Point(Top of Descent) • Loading accurate Magenta Line miles • Look for un-needed fixes in STAR’s • SID’s • IAP’s • Use local knowledge of ATC procedures (FOM Compliance) • Loading SID/STAR Constraints • Crossing altitudes & speed limits • Loading TOD & Airport Winds/Temp • PERF pg 2: DESCENT FORECAST • Anti-Ice does nothing in MD10 • No FADEC to increase N1 when Anti-ice is ONlike the MD11

  12. Using PROF in Descent Only three possible relationshipsrelative to the calculated profile (CVDP): • Above profile angle Profile FMA:IDLE • Past TOD point-IDLE power (Speed on Pitch) when lower altitude entered in FCP • On profile angle Profile FMA:PROF • When started down at TOD point-power is THRUST (Speed on Thrust) • Below profile angle Profile FMA:V/S • Descend prior to TOD requires pilot applied V/S-power isTHRUST (Speed on Thrust)

  13. Vertical Deviation Indicator (VDI) in relation to CDA Profile angle Diamond represents aircraft location relative to the Profile/ CVDA path Aircraft is Below profile (low) Autothrottles: Speed on Thrust FMA: V/S 1,000’ Aircraft is On Profile Autothrottles: Speed on Thrust FMA: PROF Mid-point bar indicates center of CVDA path- “On Profile” Aircraft is Above Profile (high) Autothrottles: Speed on Pitch FMA: IDLE 100’

  14. Starting the Descentin relationship to the Top of Descent point • If started PRIOR to calculated TOD: enter new alt in FCP- • Select an appropriate V/S then press PROF or • Enter the newly assigned altitude in MCDU INIT page - 750’fpm • Magenta V/S is “PROF Armed” condition-if CVDA profile is re-intercepted it reverts to & captures the profile: PROF • If started AT calculated TOD • Descend in PROF • ATC offers “Pilot discretion” descent • If started PAST calculated TOD • Dial in new altitude in FCP • Aircraft will descend in IDLE • Magenta IDLE in “PROF Armed” condition-if calculated profile re-intercepted it captures the profile: PROF VDI

  15. Using the VDI to determine CVDP location • A/T power TOD FL330 or IDLE Calculated descent profile (CDA) 8,000’ V/S *Requires PROF be touched after V/S initiated PROF VDI 10,000’ or 3,000’ Autothrottles: IDLE=idlePROF=thrustV/S=thrust

  16. How the MD11 tells youit knows it’s above profile… • The VDI shows diamond below center mark • Intercept “Icons” start to appear on magenta line • PERF page shows how high & long • FLTPL page shows “* DECEL” in 1R When you see these signs & enter a lower altitudein PROFILE the throttles can only go to one setting: IDLE ECON DES PATH ERROR PRED TO 5320HI 12LONG 10000 ECON UTC DIST TOD IDLE FL330 VDI Intercept with 2/3 Speed Brakes (white) Where aircraft will levelat new altitude Re-intercept on it’s own-clean wing! (magenta) 10,000’

  17. What causes an ALT ERROR AT…? • Aircraft above the CVDP • Alert always shown in the scratch pad. • When the magenta intercept ball goes past the upcoming constraint the ALT ERROR alert occurs in the scratch pad. • If the white IP is still prior to the constraint speed brakes could salvage the crossing restriction. • When the magenta IP move back prior to the constraint the error message will disappear.

  18. Where will the aircraft descend to in PROF? • Whichever is higher: • MCDU: Line 2 R–LARGE font altitude(Here HAYDN at 4,000’) • SMALL font altitudes & 1R are never honored •   FMS calculated or actual crossing altitudes                  • FCP Altitude (where would it descend now if in PROF?) 400 V/S T-P 6230 HAYDN 4000 MCGEE 1970 36L 470

  19. Advantages of flying the PROF Profile/CDA (vs. dive & drive-LVL CHG/ IDLE CLAMP) • Less fuel used • Less VFR traffic conflicts • Less noise for our neighbors • Reduced bird strike chances • Operating on a stabilized descent • Farther away from CFIT!

  20. Alternate Way to UtilizeLevel Change(& V/S for that matter!) • If Level Change is necessary – pull Level Change • Verify VDI diamond is not in the PROF capture zone • Touch PROF – Altitude FMA is now IDLE (magenta) • Aircraft now has big font MCDU altitude protection t IDLE 400’ NAV 1 250 THRUST

  21. V/S to IDLE Issue MD10-10 • Scenario: you initiate a V/S descent and hit PROF. The FMA changes to IDLE ‘unexpectedly’ • It may be a function of the margin between the FMS derived cruise speed vs. high-speed foot • V/S is Speed on Thrust. If the magenta ball is too close to high-speed foot there is insufficient speed margin to control a speed-on-thrust command • Aircraft defaults to IDLE as a result. • This has been seen less on the MD11 due to higher margins between the magenta ball and high-speed foot. • Treat Profile software like dealing with Crew Scheduling: Trust but Verify! MD11

  22. Technique for Complying with anEarly Descent to a LowerIntermediate Cruise Altitude • Scenario: you are cleared to descend from FL360 to FL320 prior to TOD then Pilot's Discretion to FL240: • Enter FL320 in the FCP (aircraft remains level FL360 due to fact that TOD is some miles ahead of aircraft) • Select INIT page on MCDU and enter 320 in line 5L as new cruise altitude • Aircraft will then begin a descent in magenta V/S at 750 fpm until reaching FL320 and will capture/HOLD • Leveling at FL320 (Magenta HOLD on the FMA) select FL240 in FCP (do not change INIT page). • Aircraft will stay at FL320 until newly calculated TOD then start down to FL240 on Profile

  23. Arrival Technique Approaching this side of the airport:use DIRECT/INBD COURSE (1R in DIRECT TO page). NOTE: being on magenta line not required foraccurate profile information NOTE: Wait until rolling out of turn before executing 1R-magenta line is drawn on ground track, not heading Aircraft ona 090° heading  Approaching from this area: Go DIRECT to HAYDN /inbound course – 270° and a magenta line (for PROF purposes) mimics a downwind-to-base pattern JSICA/180° SQIDD < 270° 36L JSICA JSICA/270° SQIDD/270°  Aircraft ona 300° heading  Aircraft ona 330° heading Jan 2008

  24. PROFILE Misc. Issues • When at an altitude that is many miles from the next FP point (30 mile final in to MEM) and ATC gives a clearance to descent, this system does not manage very low rate–of-descent vertical speeds well. Use V/S or Level Change to get the VDI diamond out of the PROF capture zone (2-3 diamond heights from center) then select PROF for CFIT protection. Comply with the AIM recommended 500 fpm ROD or ATC request. • The last appr fix (usually the FAF) is a big font altitude. If the G/S capture/Land does not capture prior to approx 100’ above that fix’s altitude, the aircraft will go into altitude hold and consequently go above glideslope.

  25. Instances When PROFWill Not Work • Switching to HOLD Mode prior to entering a holding fix • Within :03 mins of entering holding the aircraft will stop operating in PROF and switch to HOLDING mode • Greater than ~150nm from destination (full descent buffer memory issue) • If the aircraft is greater than this distance from destination a PROF decent will not be honored as the memory available to manage PROF are limited– ie: coast-in after Atlantic crossing enroute to CDG

  26. The Bottom Line: • Use PROF whenever possible/appropriate in the terminal environment as another tool to prevent CFIT • Make the aircraft complies with ATC instructions: “fly the aircraft” • Lower automation level whenever ambiguity arises as to what “HAL” is doing • Use the highest level appropriate to conditions and pilot knowledge

  27. Operating in PROFILEV/S • PROF • IDLE Your key to added CFIT protectionin the approach environment Safe • Legal • Professional

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