Call V1 3 to 5kts prior
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"I honestly believe that some of the discussions on this subject have clouded a very straight forward operating philosophy."
I agree with the above quote several posts back.
Always said V1 by V1. No "decision" needs be made at v1, no action taken, all you have to do is continue doing what you are doing.....taking off, and if an engine has quit in that very unlikely time between inside the human reaction time before hearing V.....and V1 occurring, then put in some rudder to keep the nose pointing towards the middle at the far end and wait for "rotate". No need for concerns as to whether or not that inbuilt 2 seconds exists and/or is applicable to my airframe type and if it is, does that mean I should/could use it? Christ no anyway but there is no need to "react" to anything anyway. The reaction is sit on your hands, wind the clock, take a deep breath, swear a bit, and continue the takeoff.
The argument here about when to say it is irrelevant, immaterial and beside the point your honour, as the Capt (in my outfit it was always the Captains hand on the thrust levers) you knew when you were approaching V1, and as soon as you heard the commencement of the words V1, you knew that your decision was made - no decision to make, just keep going.
What else are you going to do? "well your honour I heard him say V...... but thought he was about to tell me "Very nice takeoff roll so far skipper" so I decided to abort due to.......and ran off the end at 60kts" No of course not.
No decision to make - its been made for you - GO son go.
I agree with the above quote several posts back.
Always said V1 by V1. No "decision" needs be made at v1, no action taken, all you have to do is continue doing what you are doing.....taking off, and if an engine has quit in that very unlikely time between inside the human reaction time before hearing V.....and V1 occurring, then put in some rudder to keep the nose pointing towards the middle at the far end and wait for "rotate". No need for concerns as to whether or not that inbuilt 2 seconds exists and/or is applicable to my airframe type and if it is, does that mean I should/could use it? Christ no anyway but there is no need to "react" to anything anyway. The reaction is sit on your hands, wind the clock, take a deep breath, swear a bit, and continue the takeoff.
The argument here about when to say it is irrelevant, immaterial and beside the point your honour, as the Capt (in my outfit it was always the Captains hand on the thrust levers) you knew when you were approaching V1, and as soon as you heard the commencement of the words V1, you knew that your decision was made - no decision to make, just keep going.
What else are you going to do? "well your honour I heard him say V...... but thought he was about to tell me "Very nice takeoff roll so far skipper" so I decided to abort due to.......and ran off the end at 60kts" No of course not.
No decision to make - its been made for you - GO son go.
Only half a speed-brake
You actually can. TOW for wet must never be higher than max allowable TOW dry. But before you do, please consider:
WET figures are calculated with the decceleration force of available reverses. On the other hand, DRY figures are based on brakes only. Hence on a DRY-figure takeoff, at V1 you start to brake and should stop by runway shoulder. If you use the reversers, your stopping distance will be (much - not true) somewhat less than that (calculated). Using WET figures relies on both brakes and reversers so there are no more aces left up your sleeve.
WET figures assume minimum screen height of 15 ft. On the other hand, DRY figures require minimum of 35 ft. For balanced field, this translates to lower V1 figure to accomodate for longer braking distance on the wet tarmac.
Provided the runway is indeed DRY: should you use WET figures and elect to continue at V1, acceleration from a lower than required V1 will take longer and cover greater distance to lift-off, clearing DERA or CWY end by 15 ft. If you had used DRY V1, ENG failure (birdstrike) at the identical point of tkof roll would be still before V1 - so stopping is now a newly available option (with the extra comfort of using reversers not accredited within your ASD calculation); while an ENG failure at (the higher) dry V1 would give you 35 ft margin over the fence. The NW strut itself is 5 ft high on my aircraft.
FD (the un-real)
PS: Enter "Old+Smokey" is the search field.
-----Why
WET figures are calculated with the decceleration force of available reverses. On the other hand, DRY figures are based on brakes only. Hence on a DRY-figure takeoff, at V1 you start to brake and should stop by runway shoulder. If you use the reversers, your stopping distance will be (much - not true) somewhat less than that (calculated). Using WET figures relies on both brakes and reversers so there are no more aces left up your sleeve.
WET figures assume minimum screen height of 15 ft. On the other hand, DRY figures require minimum of 35 ft. For balanced field, this translates to lower V1 figure to accomodate for longer braking distance on the wet tarmac.
Provided the runway is indeed DRY: should you use WET figures and elect to continue at V1, acceleration from a lower than required V1 will take longer and cover greater distance to lift-off, clearing DERA or CWY end by 15 ft. If you had used DRY V1, ENG failure (birdstrike) at the identical point of tkof roll would be still before V1 - so stopping is now a newly available option (with the extra comfort of using reversers not accredited within your ASD calculation); while an ENG failure at (the higher) dry V1 would give you 35 ft margin over the fence. The NW strut itself is 5 ft high on my aircraft.
FD (the un-real)
PS: Enter "Old+Smokey" is the search field.
Last edited by FlightDetent; 11th Jun 2008 at 09:36.
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and wait for "rotate". No need for concerns as to whether or not that inbuilt 2 seconds exists and/or is applicable to my airframe type
You should commence rotation at VR on your own ASI - not on a call from the PNF. In the simulator we often see delayed rotation by the PF because he unconsciously waits then acts on the "Rotate" call from the other side of the cockpit. Often see 5-15 knots delay in rotating especially in the engine failure case simply because the PNF forgot to call and the PF waited and waited and waited.
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If you use the reversers, your stopping distance will be much less than that (calculated).
Only half a speed-brake
Thanks for pointing that out. There is no ASD charts in my books, but landing charts indicate dual reverser benefit of -3 per cent for A320. At 76t (max TOW) the actual landing distance with full manual braking indicates 1010 m showing a mere 30,3 m benefit for both reversers.
Yes, you may use the more conservative of the wet {WATES}--but---you must use the DRY Vee-speeds 
Playing TP--with the WET RWY figures
Btw--I just do a user name search
PA
Playing TP--with the WET RWY figures
Btw--I just do a user name search
PA
The problem with using Wet runway data on a Dry runway is that it's illegal.
The normal rules require that a 35 ft screen height be obtained within the TODA, and that one means of retardation (inevitably reverse thrust) be kept in reserve. That's the rules.
Then, along comes a DISPENSATION for Wet runways (Wet, not Dry or Damp) which allows the use of Reverse Thrust, and allows for a reduced screen height to 15 ft. The dispensation is allowed to be used, ONLY IF THE RUNWAY IS WET!
The dispensation entirely removes the ONLY spare performance capability remaining on a Dry runway for a RTO, and significantly reduces obstacle clearance for the continued Takeoff.
There's absolutely nothing wrong with using the more limiting of the Wet and Dry RTOW for any runway condition (except Contaminated), provided that the chosen Thrust and V-Speeds used with the actual weight are for the actual prevailing conditions, i.e. Dry (including Damp) or Wet.
Regards,
Old Smokey
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The normal rules require that a 35 ft screen height be obtained within the TODA, and that one means of retardation (inevitably reverse thrust) be kept in reserve. That's the rules.
Then, along comes a DISPENSATION for Wet runways (Wet, not Dry or Damp) which allows the use of Reverse Thrust, and allows for a reduced screen height to 15 ft. The dispensation is allowed to be used, ONLY IF THE RUNWAY IS WET!
The dispensation entirely removes the ONLY spare performance capability remaining on a Dry runway for a RTO, and significantly reduces obstacle clearance for the continued Takeoff.
There's absolutely nothing wrong with using the more limiting of the Wet and Dry RTOW for any runway condition (except Contaminated), provided that the chosen Thrust and V-Speeds used with the actual weight are for the actual prevailing conditions, i.e. Dry (including Damp) or Wet.
Regards,
Old Smokey
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Some Facts given by someone much more knowledgeable in this area than I---
PA
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As in all cases it depends on the authority under which rules you operate. We used for several years wet figures on any conditions except contaminated and reduced braking. That was approved from the local authority for operation under JAR OPS 1.
We only switched away from that when we introduced an EFB tool that of course can calculate values much closer to any relevant margin and therefore has to use dry figures on dry runways to allow further derate, higher assumed temperaturs or simply carrying more weight. Now we enjoy the fun of rotating at the numbers.
We only switched away from that when we introduced an EFB tool that of course can calculate values much closer to any relevant margin and therefore has to use dry figures on dry runways to allow further derate, higher assumed temperaturs or simply carrying more weight. Now we enjoy the fun of rotating at the numbers.
JAR OPS 1 sounds very similar to part 121-in that Air carrier OpsSpecs must be approved by an official [in the FAA --a principle operations inspector POI]---but in this case it appears that the official who allowed that didn't understand or chose to disregard the law
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Professionally quite unnecessary and worthy of the accusation of verbal diarrrhoea. Perhaps this type of nonsense is why your company requires a call by the PM of degrees of body angle rotation. Similar sentiments apply to those pilots and cabin staff who precede almost every PA with "Ladies and gentlemen, Boys and Girls..." Simply YUK!....
Verbal defecation, you say? Hardly.
We don't make cabin announcements.
The pitch angle call is part of the standard callouts, and it's a target reference attitude for a V2 climb with an engine failed; a reference and nothing more. It's not intended to be the angle to which one pitches on all engine departure. It's a parameter provided by our computerized onboard performance system which provides all the TOLD data for the departure, and yes, it's part of every standard takeoff procedure at our company.
I didn't invent the company standard procedures, but I do follow them.
Responsible procedures
with the amazing pedagological power of youtube--I found and admirable example of Clear SOPS and well executed takeoff procedure--
Look at the Pro's
http://www.youtube.com/watch?v=M3rBW94EPyc
PA
Look at the Pro's
http://www.youtube.com/watch?v=M3rBW94EPyc
PA
