Is there an audible warning on commercial aircraft if you try to land gear up?

The name of the pictureThe name of the pictureThe name of the pictureClash Royale CLAN TAG#URR8PPP












10












$begingroup$


In one of the comments on this question (under the accepted answer), someone remarks that




Aircraft can legally fly without a system to alert the crew when they are landing with gear up, etc.




Are these systems installed on commercial aircraft as a legal requirement?










share|improve this question











$endgroup$







  • 56




    $begingroup$
    Yes, you hear a loud scraping sound.
    $endgroup$
    – Tyler Durden
    Feb 12 at 12:12






  • 2




    $begingroup$
    Sometimes the warning is the sound of the gear coming down...
    $endgroup$
    – Dave
    Feb 12 at 14:38















10












$begingroup$


In one of the comments on this question (under the accepted answer), someone remarks that




Aircraft can legally fly without a system to alert the crew when they are landing with gear up, etc.




Are these systems installed on commercial aircraft as a legal requirement?










share|improve this question











$endgroup$







  • 56




    $begingroup$
    Yes, you hear a loud scraping sound.
    $endgroup$
    – Tyler Durden
    Feb 12 at 12:12






  • 2




    $begingroup$
    Sometimes the warning is the sound of the gear coming down...
    $endgroup$
    – Dave
    Feb 12 at 14:38













10












10








10


1



$begingroup$


In one of the comments on this question (under the accepted answer), someone remarks that




Aircraft can legally fly without a system to alert the crew when they are landing with gear up, etc.




Are these systems installed on commercial aircraft as a legal requirement?










share|improve this question











$endgroup$




In one of the comments on this question (under the accepted answer), someone remarks that




Aircraft can legally fly without a system to alert the crew when they are landing with gear up, etc.




Are these systems installed on commercial aircraft as a legal requirement?







safety landing commercial-aviation software






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Feb 12 at 13:59









Federico

25.5k16101153




25.5k16101153










asked Feb 12 at 11:17









CloudCloud

3,23032354




3,23032354







  • 56




    $begingroup$
    Yes, you hear a loud scraping sound.
    $endgroup$
    – Tyler Durden
    Feb 12 at 12:12






  • 2




    $begingroup$
    Sometimes the warning is the sound of the gear coming down...
    $endgroup$
    – Dave
    Feb 12 at 14:38












  • 56




    $begingroup$
    Yes, you hear a loud scraping sound.
    $endgroup$
    – Tyler Durden
    Feb 12 at 12:12






  • 2




    $begingroup$
    Sometimes the warning is the sound of the gear coming down...
    $endgroup$
    – Dave
    Feb 12 at 14:38







56




56




$begingroup$
Yes, you hear a loud scraping sound.
$endgroup$
– Tyler Durden
Feb 12 at 12:12




$begingroup$
Yes, you hear a loud scraping sound.
$endgroup$
– Tyler Durden
Feb 12 at 12:12




2




2




$begingroup$
Sometimes the warning is the sound of the gear coming down...
$endgroup$
– Dave
Feb 12 at 14:38




$begingroup$
Sometimes the warning is the sound of the gear coming down...
$endgroup$
– Dave
Feb 12 at 14:38










2 Answers
2






active

oldest

votes


















28












$begingroup$

All turbine-powered aircraft used in scheduled airline service under CFR Part 121 are required to have an approved TAWS installed;




§121.354 Terrain awareness and warning system.



(a) Airplanes manufactured after March 29, 2002. No person may operate
a turbine- powered airplane unless that airplane is equipped with an
approved terrain awareness and warning system that meets the
requirements for Class A equipment in Technical Standard Order
(TSO)-C151. The airplane must also include an approved terrain
situational awareness display.



(b) Airplanes manufactured on or before March 29, 2002. No person may
operate a turbine-powered airplane after March 29, 2005, unless that
airplane is equipped with an approved terrain awareness and warning
system that meets the requirements for Class A equipment in Technical
Standard Order (TSO)-C151. The airplane must also include an approved
terrain situational awareness display.



(c) Airplane Flight Manual. The Airplane Flight Manual shall contain
appropriate procedures for—



(1) The use of the terrain awareness and warning system; and



(2) Proper flight crew reaction in response to the terrain awareness
and warning system audio and visual warnings.




The TAWS system includes the functions of the older Ground Proximity Warning System (GPWS).



GPWS Mode 4, Flight Into Terrain with Less Than 500 Feet Terrain Clearance and Not in Landing Configuration, provides for alerts to the crew when entering a defined envelope below 500 feet (based on height and rate of descent) and the gear is not in landing configuration. There is also an alert envelope for Flaps not in landing Configuration.



The Mode 4 alert consists of an audible alert "TOO LOW, GEAR. TOO LOW, GEAR."






share|improve this answer









$endgroup$












  • $begingroup$
    Is it possible to comment on the MEL requirements about an operative TAWS? It seems possible to fly with inoperative units which de facto make the TAWS inoperative itself. E.g: In this A320 MEL, page 34-2, IR1 may be inop, in this case "The terrain function of TAWS is inoperative". There are other occurrences. It would mean, if confirmed, that it's possible to fly some days with some TAWS functions inop, maybe the gear up condition.
    $endgroup$
    – mins
    Feb 12 at 18:20







  • 4




    $begingroup$
    @mins That MEL entry and a similar for FMGC 1 apply only to the 'Terrain' function which includes the FLTA function, PDA function, and Terrain Display function. They use A/C position and inertial vector compared to the digital terrain database to predict terrain conflict. The Mode 4 alert is a GPWS function. Look at 48-01 on page 32-21 for the limitations. It may be INOP if "alternate procedures are established and used and repairs are made within 2 flight days." A failure of Radar Alt 1 will also render GPWS failed - see 42-01 on page 34-18.
    $endgroup$
    – Gerry
    Feb 12 at 20:01











  • $begingroup$
    Thanks for having digged into the MEL and added your analysis.
    $endgroup$
    – mins
    Feb 12 at 20:06







  • 4




    $begingroup$
    @Mazura - According to the black box (CVR) transcript from the accident report, "too low, gear," was sounded at 15:30:06.
    $endgroup$
    – ymb1
    Feb 12 at 22:31






  • 1




    $begingroup$
    @Cloud its not any more inaccurate than any dramatization of a RW event. They perhaps spiced up the courtroom drama for cinematic suspense. Its not a documentary. It's good entertainment if you're into that sort of thing.
    $endgroup$
    – Jamiec
    Feb 13 at 16:36


















7












$begingroup$

More basic than the TAWS requirement are the certification requirements for transport category aircraft, specifically 14 CFR 25.729(e)(2)




14 CFR 25.729 (e) Position indicator and warning device. If a retractable landing
gear is used, there must be a landing gear position indicator easily
visible to the pilot or to the appropriate crew members (as well as
necessary devices to actuate the indicator) to indicate without
ambiguity that the retractable units and their associated doors are
secured in the extended (or retracted) position. The means must be
designed as follows:



(1) If switches are used, they must be located and coupled to the
landing gear mechanical systems in a manner that prevents an erroneous
indication of “down and locked” if the landing gear is not in a fully
extended position, or of “up and locked” if the landing gear is not in
the fully retracted position. The switches may be located where they
are operated by the actual landing gear locking latch or device.



(2) The flightcrew must be given an aural warning that functions
continuously, or is periodically repeated, if a landing is attempted
when the landing gear is not locked down.



(3) The warning must be given in sufficient time to allow the landing
gear to be locked down or a go-around to be made.



(4) There must not be a manual shut-off means readily available to the
flightcrew for the warning required by paragraph (e)(2) of this
section such that it could be operated instinctively, inadvertently,
or by habitual reflexive action.



(5) The system used to generate the aural warning must be designed to
minimize false or inappropriate alerts.



(6) Failures of systems used to inhibit the landing gear aural
warning, that would prevent the warning system from operating, must be
improbable.



(7) A flightcrew alert must be provided whenever the landing gear
position is not consistent with the landing gear selector lever
position.




For the 767, these are the requirements to trigger a landing configuration warning.




(7) Landing Configuration Warning Module Function (Fig. 8)
(a) The landing configuration warning module provides aural and visual
warnings for improper airplane configuration during landing. The
module receives a dual input of |12 volts dc and +5 volts dc from power supply modules A and B.



(b) The landing configuration warning consists of the master WARNING light, siren aural warning, CONFIG light, and level A EICAS message.



(c) The landing configuration warning logic is enabled when the module
receives the landing gear not down and locked discrete signal from the
proximity switch electronics unit.



(d) When this logic is enabled and any of the following conditions occur, the landing configuration warning is provided. The outputs for each condition are as listed below:



1) The trailing edge flaps are set to 25 or 30 degrees: a) red master WARNING lights b) amber CONFIG light c) siren aural warning d) level A EICAS message



2) Both left and right thrust levers are set to idle and the radio altitude is below 800 feet: a) red master WARNING lights b) amber CONFIG light c) siren aural warning d) level A EICAS message



3) Either left or right thrust lever is set to idle, the radio
altitude is below 800 feet, and the time delay as noted below has
expired: a) red master WARNING lights b) amber CONFIG light c) siren
aural warning d) level A EICAS message NOTE: A one time delay of 140
seconds is triggered by the edge of the landing-gear-up transition
pulse. This delay allows the airplane to reach an altitude of greater
than 800 feet and prevents a warning if only one engine is throttled
back at takeoff or go-around. If either 140 seconds have elapsed or
the airplane has exceeded 800 feet altitude, the system reverts back
to providing a warning from a single engine throttle back.



4) A radio altimeter failure exists, either thrust lever is set to the idle position, and the airplane is in a clean wing configuration (flaps and slats are fully retracted): a) amber CONFIG light b) level A EICAS message



5) A radio altimeter failure exists, either thrust lever is
set to the idle position, and either the flaps or slats are not fully
retracted (NOT CLEAN WING): a) red master WARNING b) siren aural warning







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    2 Answers
    2






    active

    oldest

    votes








    2 Answers
    2






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    28












    $begingroup$

    All turbine-powered aircraft used in scheduled airline service under CFR Part 121 are required to have an approved TAWS installed;




    §121.354 Terrain awareness and warning system.



    (a) Airplanes manufactured after March 29, 2002. No person may operate
    a turbine- powered airplane unless that airplane is equipped with an
    approved terrain awareness and warning system that meets the
    requirements for Class A equipment in Technical Standard Order
    (TSO)-C151. The airplane must also include an approved terrain
    situational awareness display.



    (b) Airplanes manufactured on or before March 29, 2002. No person may
    operate a turbine-powered airplane after March 29, 2005, unless that
    airplane is equipped with an approved terrain awareness and warning
    system that meets the requirements for Class A equipment in Technical
    Standard Order (TSO)-C151. The airplane must also include an approved
    terrain situational awareness display.



    (c) Airplane Flight Manual. The Airplane Flight Manual shall contain
    appropriate procedures for—



    (1) The use of the terrain awareness and warning system; and



    (2) Proper flight crew reaction in response to the terrain awareness
    and warning system audio and visual warnings.




    The TAWS system includes the functions of the older Ground Proximity Warning System (GPWS).



    GPWS Mode 4, Flight Into Terrain with Less Than 500 Feet Terrain Clearance and Not in Landing Configuration, provides for alerts to the crew when entering a defined envelope below 500 feet (based on height and rate of descent) and the gear is not in landing configuration. There is also an alert envelope for Flaps not in landing Configuration.



    The Mode 4 alert consists of an audible alert "TOO LOW, GEAR. TOO LOW, GEAR."






    share|improve this answer









    $endgroup$












    • $begingroup$
      Is it possible to comment on the MEL requirements about an operative TAWS? It seems possible to fly with inoperative units which de facto make the TAWS inoperative itself. E.g: In this A320 MEL, page 34-2, IR1 may be inop, in this case "The terrain function of TAWS is inoperative". There are other occurrences. It would mean, if confirmed, that it's possible to fly some days with some TAWS functions inop, maybe the gear up condition.
      $endgroup$
      – mins
      Feb 12 at 18:20







    • 4




      $begingroup$
      @mins That MEL entry and a similar for FMGC 1 apply only to the 'Terrain' function which includes the FLTA function, PDA function, and Terrain Display function. They use A/C position and inertial vector compared to the digital terrain database to predict terrain conflict. The Mode 4 alert is a GPWS function. Look at 48-01 on page 32-21 for the limitations. It may be INOP if "alternate procedures are established and used and repairs are made within 2 flight days." A failure of Radar Alt 1 will also render GPWS failed - see 42-01 on page 34-18.
      $endgroup$
      – Gerry
      Feb 12 at 20:01











    • $begingroup$
      Thanks for having digged into the MEL and added your analysis.
      $endgroup$
      – mins
      Feb 12 at 20:06







    • 4




      $begingroup$
      @Mazura - According to the black box (CVR) transcript from the accident report, "too low, gear," was sounded at 15:30:06.
      $endgroup$
      – ymb1
      Feb 12 at 22:31






    • 1




      $begingroup$
      @Cloud its not any more inaccurate than any dramatization of a RW event. They perhaps spiced up the courtroom drama for cinematic suspense. Its not a documentary. It's good entertainment if you're into that sort of thing.
      $endgroup$
      – Jamiec
      Feb 13 at 16:36















    28












    $begingroup$

    All turbine-powered aircraft used in scheduled airline service under CFR Part 121 are required to have an approved TAWS installed;




    §121.354 Terrain awareness and warning system.



    (a) Airplanes manufactured after March 29, 2002. No person may operate
    a turbine- powered airplane unless that airplane is equipped with an
    approved terrain awareness and warning system that meets the
    requirements for Class A equipment in Technical Standard Order
    (TSO)-C151. The airplane must also include an approved terrain
    situational awareness display.



    (b) Airplanes manufactured on or before March 29, 2002. No person may
    operate a turbine-powered airplane after March 29, 2005, unless that
    airplane is equipped with an approved terrain awareness and warning
    system that meets the requirements for Class A equipment in Technical
    Standard Order (TSO)-C151. The airplane must also include an approved
    terrain situational awareness display.



    (c) Airplane Flight Manual. The Airplane Flight Manual shall contain
    appropriate procedures for—



    (1) The use of the terrain awareness and warning system; and



    (2) Proper flight crew reaction in response to the terrain awareness
    and warning system audio and visual warnings.




    The TAWS system includes the functions of the older Ground Proximity Warning System (GPWS).



    GPWS Mode 4, Flight Into Terrain with Less Than 500 Feet Terrain Clearance and Not in Landing Configuration, provides for alerts to the crew when entering a defined envelope below 500 feet (based on height and rate of descent) and the gear is not in landing configuration. There is also an alert envelope for Flaps not in landing Configuration.



    The Mode 4 alert consists of an audible alert "TOO LOW, GEAR. TOO LOW, GEAR."






    share|improve this answer









    $endgroup$












    • $begingroup$
      Is it possible to comment on the MEL requirements about an operative TAWS? It seems possible to fly with inoperative units which de facto make the TAWS inoperative itself. E.g: In this A320 MEL, page 34-2, IR1 may be inop, in this case "The terrain function of TAWS is inoperative". There are other occurrences. It would mean, if confirmed, that it's possible to fly some days with some TAWS functions inop, maybe the gear up condition.
      $endgroup$
      – mins
      Feb 12 at 18:20







    • 4




      $begingroup$
      @mins That MEL entry and a similar for FMGC 1 apply only to the 'Terrain' function which includes the FLTA function, PDA function, and Terrain Display function. They use A/C position and inertial vector compared to the digital terrain database to predict terrain conflict. The Mode 4 alert is a GPWS function. Look at 48-01 on page 32-21 for the limitations. It may be INOP if "alternate procedures are established and used and repairs are made within 2 flight days." A failure of Radar Alt 1 will also render GPWS failed - see 42-01 on page 34-18.
      $endgroup$
      – Gerry
      Feb 12 at 20:01











    • $begingroup$
      Thanks for having digged into the MEL and added your analysis.
      $endgroup$
      – mins
      Feb 12 at 20:06







    • 4




      $begingroup$
      @Mazura - According to the black box (CVR) transcript from the accident report, "too low, gear," was sounded at 15:30:06.
      $endgroup$
      – ymb1
      Feb 12 at 22:31






    • 1




      $begingroup$
      @Cloud its not any more inaccurate than any dramatization of a RW event. They perhaps spiced up the courtroom drama for cinematic suspense. Its not a documentary. It's good entertainment if you're into that sort of thing.
      $endgroup$
      – Jamiec
      Feb 13 at 16:36













    28












    28








    28





    $begingroup$

    All turbine-powered aircraft used in scheduled airline service under CFR Part 121 are required to have an approved TAWS installed;




    §121.354 Terrain awareness and warning system.



    (a) Airplanes manufactured after March 29, 2002. No person may operate
    a turbine- powered airplane unless that airplane is equipped with an
    approved terrain awareness and warning system that meets the
    requirements for Class A equipment in Technical Standard Order
    (TSO)-C151. The airplane must also include an approved terrain
    situational awareness display.



    (b) Airplanes manufactured on or before March 29, 2002. No person may
    operate a turbine-powered airplane after March 29, 2005, unless that
    airplane is equipped with an approved terrain awareness and warning
    system that meets the requirements for Class A equipment in Technical
    Standard Order (TSO)-C151. The airplane must also include an approved
    terrain situational awareness display.



    (c) Airplane Flight Manual. The Airplane Flight Manual shall contain
    appropriate procedures for—



    (1) The use of the terrain awareness and warning system; and



    (2) Proper flight crew reaction in response to the terrain awareness
    and warning system audio and visual warnings.




    The TAWS system includes the functions of the older Ground Proximity Warning System (GPWS).



    GPWS Mode 4, Flight Into Terrain with Less Than 500 Feet Terrain Clearance and Not in Landing Configuration, provides for alerts to the crew when entering a defined envelope below 500 feet (based on height and rate of descent) and the gear is not in landing configuration. There is also an alert envelope for Flaps not in landing Configuration.



    The Mode 4 alert consists of an audible alert "TOO LOW, GEAR. TOO LOW, GEAR."






    share|improve this answer









    $endgroup$



    All turbine-powered aircraft used in scheduled airline service under CFR Part 121 are required to have an approved TAWS installed;




    §121.354 Terrain awareness and warning system.



    (a) Airplanes manufactured after March 29, 2002. No person may operate
    a turbine- powered airplane unless that airplane is equipped with an
    approved terrain awareness and warning system that meets the
    requirements for Class A equipment in Technical Standard Order
    (TSO)-C151. The airplane must also include an approved terrain
    situational awareness display.



    (b) Airplanes manufactured on or before March 29, 2002. No person may
    operate a turbine-powered airplane after March 29, 2005, unless that
    airplane is equipped with an approved terrain awareness and warning
    system that meets the requirements for Class A equipment in Technical
    Standard Order (TSO)-C151. The airplane must also include an approved
    terrain situational awareness display.



    (c) Airplane Flight Manual. The Airplane Flight Manual shall contain
    appropriate procedures for—



    (1) The use of the terrain awareness and warning system; and



    (2) Proper flight crew reaction in response to the terrain awareness
    and warning system audio and visual warnings.




    The TAWS system includes the functions of the older Ground Proximity Warning System (GPWS).



    GPWS Mode 4, Flight Into Terrain with Less Than 500 Feet Terrain Clearance and Not in Landing Configuration, provides for alerts to the crew when entering a defined envelope below 500 feet (based on height and rate of descent) and the gear is not in landing configuration. There is also an alert envelope for Flaps not in landing Configuration.



    The Mode 4 alert consists of an audible alert "TOO LOW, GEAR. TOO LOW, GEAR."







    share|improve this answer












    share|improve this answer



    share|improve this answer










    answered Feb 12 at 12:44









    GerryGerry

    11k13151




    11k13151











    • $begingroup$
      Is it possible to comment on the MEL requirements about an operative TAWS? It seems possible to fly with inoperative units which de facto make the TAWS inoperative itself. E.g: In this A320 MEL, page 34-2, IR1 may be inop, in this case "The terrain function of TAWS is inoperative". There are other occurrences. It would mean, if confirmed, that it's possible to fly some days with some TAWS functions inop, maybe the gear up condition.
      $endgroup$
      – mins
      Feb 12 at 18:20







    • 4




      $begingroup$
      @mins That MEL entry and a similar for FMGC 1 apply only to the 'Terrain' function which includes the FLTA function, PDA function, and Terrain Display function. They use A/C position and inertial vector compared to the digital terrain database to predict terrain conflict. The Mode 4 alert is a GPWS function. Look at 48-01 on page 32-21 for the limitations. It may be INOP if "alternate procedures are established and used and repairs are made within 2 flight days." A failure of Radar Alt 1 will also render GPWS failed - see 42-01 on page 34-18.
      $endgroup$
      – Gerry
      Feb 12 at 20:01











    • $begingroup$
      Thanks for having digged into the MEL and added your analysis.
      $endgroup$
      – mins
      Feb 12 at 20:06







    • 4




      $begingroup$
      @Mazura - According to the black box (CVR) transcript from the accident report, "too low, gear," was sounded at 15:30:06.
      $endgroup$
      – ymb1
      Feb 12 at 22:31






    • 1




      $begingroup$
      @Cloud its not any more inaccurate than any dramatization of a RW event. They perhaps spiced up the courtroom drama for cinematic suspense. Its not a documentary. It's good entertainment if you're into that sort of thing.
      $endgroup$
      – Jamiec
      Feb 13 at 16:36
















    • $begingroup$
      Is it possible to comment on the MEL requirements about an operative TAWS? It seems possible to fly with inoperative units which de facto make the TAWS inoperative itself. E.g: In this A320 MEL, page 34-2, IR1 may be inop, in this case "The terrain function of TAWS is inoperative". There are other occurrences. It would mean, if confirmed, that it's possible to fly some days with some TAWS functions inop, maybe the gear up condition.
      $endgroup$
      – mins
      Feb 12 at 18:20







    • 4




      $begingroup$
      @mins That MEL entry and a similar for FMGC 1 apply only to the 'Terrain' function which includes the FLTA function, PDA function, and Terrain Display function. They use A/C position and inertial vector compared to the digital terrain database to predict terrain conflict. The Mode 4 alert is a GPWS function. Look at 48-01 on page 32-21 for the limitations. It may be INOP if "alternate procedures are established and used and repairs are made within 2 flight days." A failure of Radar Alt 1 will also render GPWS failed - see 42-01 on page 34-18.
      $endgroup$
      – Gerry
      Feb 12 at 20:01











    • $begingroup$
      Thanks for having digged into the MEL and added your analysis.
      $endgroup$
      – mins
      Feb 12 at 20:06







    • 4




      $begingroup$
      @Mazura - According to the black box (CVR) transcript from the accident report, "too low, gear," was sounded at 15:30:06.
      $endgroup$
      – ymb1
      Feb 12 at 22:31






    • 1




      $begingroup$
      @Cloud its not any more inaccurate than any dramatization of a RW event. They perhaps spiced up the courtroom drama for cinematic suspense. Its not a documentary. It's good entertainment if you're into that sort of thing.
      $endgroup$
      – Jamiec
      Feb 13 at 16:36















    $begingroup$
    Is it possible to comment on the MEL requirements about an operative TAWS? It seems possible to fly with inoperative units which de facto make the TAWS inoperative itself. E.g: In this A320 MEL, page 34-2, IR1 may be inop, in this case "The terrain function of TAWS is inoperative". There are other occurrences. It would mean, if confirmed, that it's possible to fly some days with some TAWS functions inop, maybe the gear up condition.
    $endgroup$
    – mins
    Feb 12 at 18:20





    $begingroup$
    Is it possible to comment on the MEL requirements about an operative TAWS? It seems possible to fly with inoperative units which de facto make the TAWS inoperative itself. E.g: In this A320 MEL, page 34-2, IR1 may be inop, in this case "The terrain function of TAWS is inoperative". There are other occurrences. It would mean, if confirmed, that it's possible to fly some days with some TAWS functions inop, maybe the gear up condition.
    $endgroup$
    – mins
    Feb 12 at 18:20





    4




    4




    $begingroup$
    @mins That MEL entry and a similar for FMGC 1 apply only to the 'Terrain' function which includes the FLTA function, PDA function, and Terrain Display function. They use A/C position and inertial vector compared to the digital terrain database to predict terrain conflict. The Mode 4 alert is a GPWS function. Look at 48-01 on page 32-21 for the limitations. It may be INOP if "alternate procedures are established and used and repairs are made within 2 flight days." A failure of Radar Alt 1 will also render GPWS failed - see 42-01 on page 34-18.
    $endgroup$
    – Gerry
    Feb 12 at 20:01





    $begingroup$
    @mins That MEL entry and a similar for FMGC 1 apply only to the 'Terrain' function which includes the FLTA function, PDA function, and Terrain Display function. They use A/C position and inertial vector compared to the digital terrain database to predict terrain conflict. The Mode 4 alert is a GPWS function. Look at 48-01 on page 32-21 for the limitations. It may be INOP if "alternate procedures are established and used and repairs are made within 2 flight days." A failure of Radar Alt 1 will also render GPWS failed - see 42-01 on page 34-18.
    $endgroup$
    – Gerry
    Feb 12 at 20:01













    $begingroup$
    Thanks for having digged into the MEL and added your analysis.
    $endgroup$
    – mins
    Feb 12 at 20:06





    $begingroup$
    Thanks for having digged into the MEL and added your analysis.
    $endgroup$
    – mins
    Feb 12 at 20:06





    4




    4




    $begingroup$
    @Mazura - According to the black box (CVR) transcript from the accident report, "too low, gear," was sounded at 15:30:06.
    $endgroup$
    – ymb1
    Feb 12 at 22:31




    $begingroup$
    @Mazura - According to the black box (CVR) transcript from the accident report, "too low, gear," was sounded at 15:30:06.
    $endgroup$
    – ymb1
    Feb 12 at 22:31




    1




    1




    $begingroup$
    @Cloud its not any more inaccurate than any dramatization of a RW event. They perhaps spiced up the courtroom drama for cinematic suspense. Its not a documentary. It's good entertainment if you're into that sort of thing.
    $endgroup$
    – Jamiec
    Feb 13 at 16:36




    $begingroup$
    @Cloud its not any more inaccurate than any dramatization of a RW event. They perhaps spiced up the courtroom drama for cinematic suspense. Its not a documentary. It's good entertainment if you're into that sort of thing.
    $endgroup$
    – Jamiec
    Feb 13 at 16:36











    7












    $begingroup$

    More basic than the TAWS requirement are the certification requirements for transport category aircraft, specifically 14 CFR 25.729(e)(2)




    14 CFR 25.729 (e) Position indicator and warning device. If a retractable landing
    gear is used, there must be a landing gear position indicator easily
    visible to the pilot or to the appropriate crew members (as well as
    necessary devices to actuate the indicator) to indicate without
    ambiguity that the retractable units and their associated doors are
    secured in the extended (or retracted) position. The means must be
    designed as follows:



    (1) If switches are used, they must be located and coupled to the
    landing gear mechanical systems in a manner that prevents an erroneous
    indication of “down and locked” if the landing gear is not in a fully
    extended position, or of “up and locked” if the landing gear is not in
    the fully retracted position. The switches may be located where they
    are operated by the actual landing gear locking latch or device.



    (2) The flightcrew must be given an aural warning that functions
    continuously, or is periodically repeated, if a landing is attempted
    when the landing gear is not locked down.



    (3) The warning must be given in sufficient time to allow the landing
    gear to be locked down or a go-around to be made.



    (4) There must not be a manual shut-off means readily available to the
    flightcrew for the warning required by paragraph (e)(2) of this
    section such that it could be operated instinctively, inadvertently,
    or by habitual reflexive action.



    (5) The system used to generate the aural warning must be designed to
    minimize false or inappropriate alerts.



    (6) Failures of systems used to inhibit the landing gear aural
    warning, that would prevent the warning system from operating, must be
    improbable.



    (7) A flightcrew alert must be provided whenever the landing gear
    position is not consistent with the landing gear selector lever
    position.




    For the 767, these are the requirements to trigger a landing configuration warning.




    (7) Landing Configuration Warning Module Function (Fig. 8)
    (a) The landing configuration warning module provides aural and visual
    warnings for improper airplane configuration during landing. The
    module receives a dual input of |12 volts dc and +5 volts dc from power supply modules A and B.



    (b) The landing configuration warning consists of the master WARNING light, siren aural warning, CONFIG light, and level A EICAS message.



    (c) The landing configuration warning logic is enabled when the module
    receives the landing gear not down and locked discrete signal from the
    proximity switch electronics unit.



    (d) When this logic is enabled and any of the following conditions occur, the landing configuration warning is provided. The outputs for each condition are as listed below:



    1) The trailing edge flaps are set to 25 or 30 degrees: a) red master WARNING lights b) amber CONFIG light c) siren aural warning d) level A EICAS message



    2) Both left and right thrust levers are set to idle and the radio altitude is below 800 feet: a) red master WARNING lights b) amber CONFIG light c) siren aural warning d) level A EICAS message



    3) Either left or right thrust lever is set to idle, the radio
    altitude is below 800 feet, and the time delay as noted below has
    expired: a) red master WARNING lights b) amber CONFIG light c) siren
    aural warning d) level A EICAS message NOTE: A one time delay of 140
    seconds is triggered by the edge of the landing-gear-up transition
    pulse. This delay allows the airplane to reach an altitude of greater
    than 800 feet and prevents a warning if only one engine is throttled
    back at takeoff or go-around. If either 140 seconds have elapsed or
    the airplane has exceeded 800 feet altitude, the system reverts back
    to providing a warning from a single engine throttle back.



    4) A radio altimeter failure exists, either thrust lever is set to the idle position, and the airplane is in a clean wing configuration (flaps and slats are fully retracted): a) amber CONFIG light b) level A EICAS message



    5) A radio altimeter failure exists, either thrust lever is
    set to the idle position, and either the flaps or slats are not fully
    retracted (NOT CLEAN WING): a) red master WARNING b) siren aural warning







    share|improve this answer











    $endgroup$

















      7












      $begingroup$

      More basic than the TAWS requirement are the certification requirements for transport category aircraft, specifically 14 CFR 25.729(e)(2)




      14 CFR 25.729 (e) Position indicator and warning device. If a retractable landing
      gear is used, there must be a landing gear position indicator easily
      visible to the pilot or to the appropriate crew members (as well as
      necessary devices to actuate the indicator) to indicate without
      ambiguity that the retractable units and their associated doors are
      secured in the extended (or retracted) position. The means must be
      designed as follows:



      (1) If switches are used, they must be located and coupled to the
      landing gear mechanical systems in a manner that prevents an erroneous
      indication of “down and locked” if the landing gear is not in a fully
      extended position, or of “up and locked” if the landing gear is not in
      the fully retracted position. The switches may be located where they
      are operated by the actual landing gear locking latch or device.



      (2) The flightcrew must be given an aural warning that functions
      continuously, or is periodically repeated, if a landing is attempted
      when the landing gear is not locked down.



      (3) The warning must be given in sufficient time to allow the landing
      gear to be locked down or a go-around to be made.



      (4) There must not be a manual shut-off means readily available to the
      flightcrew for the warning required by paragraph (e)(2) of this
      section such that it could be operated instinctively, inadvertently,
      or by habitual reflexive action.



      (5) The system used to generate the aural warning must be designed to
      minimize false or inappropriate alerts.



      (6) Failures of systems used to inhibit the landing gear aural
      warning, that would prevent the warning system from operating, must be
      improbable.



      (7) A flightcrew alert must be provided whenever the landing gear
      position is not consistent with the landing gear selector lever
      position.




      For the 767, these are the requirements to trigger a landing configuration warning.




      (7) Landing Configuration Warning Module Function (Fig. 8)
      (a) The landing configuration warning module provides aural and visual
      warnings for improper airplane configuration during landing. The
      module receives a dual input of |12 volts dc and +5 volts dc from power supply modules A and B.



      (b) The landing configuration warning consists of the master WARNING light, siren aural warning, CONFIG light, and level A EICAS message.



      (c) The landing configuration warning logic is enabled when the module
      receives the landing gear not down and locked discrete signal from the
      proximity switch electronics unit.



      (d) When this logic is enabled and any of the following conditions occur, the landing configuration warning is provided. The outputs for each condition are as listed below:



      1) The trailing edge flaps are set to 25 or 30 degrees: a) red master WARNING lights b) amber CONFIG light c) siren aural warning d) level A EICAS message



      2) Both left and right thrust levers are set to idle and the radio altitude is below 800 feet: a) red master WARNING lights b) amber CONFIG light c) siren aural warning d) level A EICAS message



      3) Either left or right thrust lever is set to idle, the radio
      altitude is below 800 feet, and the time delay as noted below has
      expired: a) red master WARNING lights b) amber CONFIG light c) siren
      aural warning d) level A EICAS message NOTE: A one time delay of 140
      seconds is triggered by the edge of the landing-gear-up transition
      pulse. This delay allows the airplane to reach an altitude of greater
      than 800 feet and prevents a warning if only one engine is throttled
      back at takeoff or go-around. If either 140 seconds have elapsed or
      the airplane has exceeded 800 feet altitude, the system reverts back
      to providing a warning from a single engine throttle back.



      4) A radio altimeter failure exists, either thrust lever is set to the idle position, and the airplane is in a clean wing configuration (flaps and slats are fully retracted): a) amber CONFIG light b) level A EICAS message



      5) A radio altimeter failure exists, either thrust lever is
      set to the idle position, and either the flaps or slats are not fully
      retracted (NOT CLEAN WING): a) red master WARNING b) siren aural warning







      share|improve this answer











      $endgroup$















        7












        7








        7





        $begingroup$

        More basic than the TAWS requirement are the certification requirements for transport category aircraft, specifically 14 CFR 25.729(e)(2)




        14 CFR 25.729 (e) Position indicator and warning device. If a retractable landing
        gear is used, there must be a landing gear position indicator easily
        visible to the pilot or to the appropriate crew members (as well as
        necessary devices to actuate the indicator) to indicate without
        ambiguity that the retractable units and their associated doors are
        secured in the extended (or retracted) position. The means must be
        designed as follows:



        (1) If switches are used, they must be located and coupled to the
        landing gear mechanical systems in a manner that prevents an erroneous
        indication of “down and locked” if the landing gear is not in a fully
        extended position, or of “up and locked” if the landing gear is not in
        the fully retracted position. The switches may be located where they
        are operated by the actual landing gear locking latch or device.



        (2) The flightcrew must be given an aural warning that functions
        continuously, or is periodically repeated, if a landing is attempted
        when the landing gear is not locked down.



        (3) The warning must be given in sufficient time to allow the landing
        gear to be locked down or a go-around to be made.



        (4) There must not be a manual shut-off means readily available to the
        flightcrew for the warning required by paragraph (e)(2) of this
        section such that it could be operated instinctively, inadvertently,
        or by habitual reflexive action.



        (5) The system used to generate the aural warning must be designed to
        minimize false or inappropriate alerts.



        (6) Failures of systems used to inhibit the landing gear aural
        warning, that would prevent the warning system from operating, must be
        improbable.



        (7) A flightcrew alert must be provided whenever the landing gear
        position is not consistent with the landing gear selector lever
        position.




        For the 767, these are the requirements to trigger a landing configuration warning.




        (7) Landing Configuration Warning Module Function (Fig. 8)
        (a) The landing configuration warning module provides aural and visual
        warnings for improper airplane configuration during landing. The
        module receives a dual input of |12 volts dc and +5 volts dc from power supply modules A and B.



        (b) The landing configuration warning consists of the master WARNING light, siren aural warning, CONFIG light, and level A EICAS message.



        (c) The landing configuration warning logic is enabled when the module
        receives the landing gear not down and locked discrete signal from the
        proximity switch electronics unit.



        (d) When this logic is enabled and any of the following conditions occur, the landing configuration warning is provided. The outputs for each condition are as listed below:



        1) The trailing edge flaps are set to 25 or 30 degrees: a) red master WARNING lights b) amber CONFIG light c) siren aural warning d) level A EICAS message



        2) Both left and right thrust levers are set to idle and the radio altitude is below 800 feet: a) red master WARNING lights b) amber CONFIG light c) siren aural warning d) level A EICAS message



        3) Either left or right thrust lever is set to idle, the radio
        altitude is below 800 feet, and the time delay as noted below has
        expired: a) red master WARNING lights b) amber CONFIG light c) siren
        aural warning d) level A EICAS message NOTE: A one time delay of 140
        seconds is triggered by the edge of the landing-gear-up transition
        pulse. This delay allows the airplane to reach an altitude of greater
        than 800 feet and prevents a warning if only one engine is throttled
        back at takeoff or go-around. If either 140 seconds have elapsed or
        the airplane has exceeded 800 feet altitude, the system reverts back
        to providing a warning from a single engine throttle back.



        4) A radio altimeter failure exists, either thrust lever is set to the idle position, and the airplane is in a clean wing configuration (flaps and slats are fully retracted): a) amber CONFIG light b) level A EICAS message



        5) A radio altimeter failure exists, either thrust lever is
        set to the idle position, and either the flaps or slats are not fully
        retracted (NOT CLEAN WING): a) red master WARNING b) siren aural warning







        share|improve this answer











        $endgroup$



        More basic than the TAWS requirement are the certification requirements for transport category aircraft, specifically 14 CFR 25.729(e)(2)




        14 CFR 25.729 (e) Position indicator and warning device. If a retractable landing
        gear is used, there must be a landing gear position indicator easily
        visible to the pilot or to the appropriate crew members (as well as
        necessary devices to actuate the indicator) to indicate without
        ambiguity that the retractable units and their associated doors are
        secured in the extended (or retracted) position. The means must be
        designed as follows:



        (1) If switches are used, they must be located and coupled to the
        landing gear mechanical systems in a manner that prevents an erroneous
        indication of “down and locked” if the landing gear is not in a fully
        extended position, or of “up and locked” if the landing gear is not in
        the fully retracted position. The switches may be located where they
        are operated by the actual landing gear locking latch or device.



        (2) The flightcrew must be given an aural warning that functions
        continuously, or is periodically repeated, if a landing is attempted
        when the landing gear is not locked down.



        (3) The warning must be given in sufficient time to allow the landing
        gear to be locked down or a go-around to be made.



        (4) There must not be a manual shut-off means readily available to the
        flightcrew for the warning required by paragraph (e)(2) of this
        section such that it could be operated instinctively, inadvertently,
        or by habitual reflexive action.



        (5) The system used to generate the aural warning must be designed to
        minimize false or inappropriate alerts.



        (6) Failures of systems used to inhibit the landing gear aural
        warning, that would prevent the warning system from operating, must be
        improbable.



        (7) A flightcrew alert must be provided whenever the landing gear
        position is not consistent with the landing gear selector lever
        position.




        For the 767, these are the requirements to trigger a landing configuration warning.




        (7) Landing Configuration Warning Module Function (Fig. 8)
        (a) The landing configuration warning module provides aural and visual
        warnings for improper airplane configuration during landing. The
        module receives a dual input of |12 volts dc and +5 volts dc from power supply modules A and B.



        (b) The landing configuration warning consists of the master WARNING light, siren aural warning, CONFIG light, and level A EICAS message.



        (c) The landing configuration warning logic is enabled when the module
        receives the landing gear not down and locked discrete signal from the
        proximity switch electronics unit.



        (d) When this logic is enabled and any of the following conditions occur, the landing configuration warning is provided. The outputs for each condition are as listed below:



        1) The trailing edge flaps are set to 25 or 30 degrees: a) red master WARNING lights b) amber CONFIG light c) siren aural warning d) level A EICAS message



        2) Both left and right thrust levers are set to idle and the radio altitude is below 800 feet: a) red master WARNING lights b) amber CONFIG light c) siren aural warning d) level A EICAS message



        3) Either left or right thrust lever is set to idle, the radio
        altitude is below 800 feet, and the time delay as noted below has
        expired: a) red master WARNING lights b) amber CONFIG light c) siren
        aural warning d) level A EICAS message NOTE: A one time delay of 140
        seconds is triggered by the edge of the landing-gear-up transition
        pulse. This delay allows the airplane to reach an altitude of greater
        than 800 feet and prevents a warning if only one engine is throttled
        back at takeoff or go-around. If either 140 seconds have elapsed or
        the airplane has exceeded 800 feet altitude, the system reverts back
        to providing a warning from a single engine throttle back.



        4) A radio altimeter failure exists, either thrust lever is set to the idle position, and the airplane is in a clean wing configuration (flaps and slats are fully retracted): a) amber CONFIG light b) level A EICAS message



        5) A radio altimeter failure exists, either thrust lever is
        set to the idle position, and either the flaps or slats are not fully
        retracted (NOT CLEAN WING): a) red master WARNING b) siren aural warning








        share|improve this answer














        share|improve this answer



        share|improve this answer








        edited Feb 12 at 20:50

























        answered Feb 12 at 20:34









        Sports RacerSports Racer

        2,481819




        2,481819



























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