VB Smooth Landing Kings
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The original 250 below 10 was brought in by the FAA after a 727 clobbered a 172 and both aircraft were destroyed. In the States, it is a law that no one goes above 250 below 10 for that reason. ATC nor pilot can request a waiver to that law.
The impact energy of a bird strike increases with the square of the TAS - not the IAS. I understand from CASA sources that the dangers associated with bird impact damage during high speed below 10,000 ft will be the subject of an article in the forthcoming issue of Flight Safety Australia. Watch this space.
Read the report on the loss of an RAAF F-111 near Evans Head some years ago when a bird was hit at 560 knots at low level killing the crew when the windscreen stove in. Or the bird strike on the stabiliser of a Viscount in Canada at 280 IAS which resulted in the structural failure of the stabiliser and loss of the Viscount.
Sure, materials might be strengthend in Boeings and Airbus since those days, but 320 knots to 1500 ft as some scribe boasted earlier is poor airmanship - a term incidently that has gone out of vogue in recent years.
The impact energy of a bird strike increases with the square of the TAS - not the IAS. I understand from CASA sources that the dangers associated with bird impact damage during high speed below 10,000 ft will be the subject of an article in the forthcoming issue of Flight Safety Australia. Watch this space.
Read the report on the loss of an RAAF F-111 near Evans Head some years ago when a bird was hit at 560 knots at low level killing the crew when the windscreen stove in. Or the bird strike on the stabiliser of a Viscount in Canada at 280 IAS which resulted in the structural failure of the stabiliser and loss of the Viscount.
Sure, materials might be strengthend in Boeings and Airbus since those days, but 320 knots to 1500 ft as some scribe boasted earlier is poor airmanship - a term incidently that has gone out of vogue in recent years.
HSWL
Not true. If you require high speed due operational reasons you can most definitely get it. For most heavies 250kts below 10000” isn’t practical or possible on departure, as you can’t clean up.
In the States, it is a law that no one goes above 250 below 10 for that reason. ATC nor pilot can request a waiver to that law.
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was always led to believe by a US FAA instructor ex military (of course may be BS) that the reason the 250<10 in the states (when originally applied however many years ago) was to aid in the detection of high speed, low level cruise missiles. As he also said, this is now largely irrelevant as most jets easily exceed these speeds.
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just as well that we have HWSL to set us straight in respect to operating at 320 kts below ten and other airmanship matters!
Him being a super hot PPL and all!!!!
His post is the best laugh I've had in years on Prune!
Him being a super hot PPL and all!!!!
His post is the best laugh I've had in years on Prune!
Folks,
Discussions on speed bring all sorts of theories out of the wood work.
First, a little bit of history. 250 below 10,000, 210 below 3000 started as ATC speed limits in USA, but nothing to do with hitting a C-172, although a jet hitting a Constellation off KJFK got everyone’s attention at the time. Amazingly, only one fatality, the Captain of the Connie, and that happened on the ground, look it up, it was an amazing piece of airmanship.
It was all about making life easy for ATC, with early primitive radar, long before Mode C transponders etc., and big pistons ruled the airways, and the handful of airlines that had these new fangled jet thingies (like Qantas and Pan Am) had to fit in, majority ruled.
When the cost of fuel was no consideration, high speed descents were good fun. At one stage, the QF STANDARD descent was 0.88/360 to 3000’ ( B747), earlier, 0.86/360 in the B707. If conditions were suitable, nobody batted an eyelid if you maintained 360 to 1500’. In fact, the “decision height” for a diversion of a jet was often FL 250, so once your were committed to land, the faster you got on the ground the better, before the next Cb rolled in. Made for some interesting approaches when you had nowhere else to go.
Unfortunately, various “oil price shocks” over the years are what is really behind present descent profiles, descending from the final FL at approximately ( approximately is there for the pickers of nits) minimum drag, with the aim of only increasing power on final to stabilize the approach ( 500’VMC, 1000’IMC) will be minimum fuel burn.
Given the laws of aerodynamics, and the real world of ATC “help”, as it turns out 300/250/210 generally isn’t too far off the best profile for quite a range of aircraft, and aren’t too far from the middle of most turbulence penetration envelopes, either.
Thus, what started out in the late’50’s to keep B707/DC-8 out of the way of L049/749/1049/DC-4/6/6B/7A,B,C/ C 240/340/ Martin 202/303 etc has endured, for more reasons than one, but the history is a whole lot simpler than the last four pages would suggest.
As for birdstrikes, the various BCARS used to throw up 7000 and below as the bird strike area for certification ( I have no idea where the 8000’s or so quoted came from), while SFAR 422B ( now Part 25) used 10,000’. Presumably the pommie pigeon couldn’t soar to the heights of the FAA Bald Eagle.
By the way, weren’t any cruise missiles in late’50’s/early 60’s, just dumb bombs --- but given the yield, they didn’t need to be smart.
Tootle pip!!
Discussions on speed bring all sorts of theories out of the wood work.
First, a little bit of history. 250 below 10,000, 210 below 3000 started as ATC speed limits in USA, but nothing to do with hitting a C-172, although a jet hitting a Constellation off KJFK got everyone’s attention at the time. Amazingly, only one fatality, the Captain of the Connie, and that happened on the ground, look it up, it was an amazing piece of airmanship.
It was all about making life easy for ATC, with early primitive radar, long before Mode C transponders etc., and big pistons ruled the airways, and the handful of airlines that had these new fangled jet thingies (like Qantas and Pan Am) had to fit in, majority ruled.
When the cost of fuel was no consideration, high speed descents were good fun. At one stage, the QF STANDARD descent was 0.88/360 to 3000’ ( B747), earlier, 0.86/360 in the B707. If conditions were suitable, nobody batted an eyelid if you maintained 360 to 1500’. In fact, the “decision height” for a diversion of a jet was often FL 250, so once your were committed to land, the faster you got on the ground the better, before the next Cb rolled in. Made for some interesting approaches when you had nowhere else to go.
Unfortunately, various “oil price shocks” over the years are what is really behind present descent profiles, descending from the final FL at approximately ( approximately is there for the pickers of nits) minimum drag, with the aim of only increasing power on final to stabilize the approach ( 500’VMC, 1000’IMC) will be minimum fuel burn.
Given the laws of aerodynamics, and the real world of ATC “help”, as it turns out 300/250/210 generally isn’t too far off the best profile for quite a range of aircraft, and aren’t too far from the middle of most turbulence penetration envelopes, either.
Thus, what started out in the late’50’s to keep B707/DC-8 out of the way of L049/749/1049/DC-4/6/6B/7A,B,C/ C 240/340/ Martin 202/303 etc has endured, for more reasons than one, but the history is a whole lot simpler than the last four pages would suggest.
As for birdstrikes, the various BCARS used to throw up 7000 and below as the bird strike area for certification ( I have no idea where the 8000’s or so quoted came from), while SFAR 422B ( now Part 25) used 10,000’. Presumably the pommie pigeon couldn’t soar to the heights of the FAA Bald Eagle.
By the way, weren’t any cruise missiles in late’50’s/early 60’s, just dumb bombs --- but given the yield, they didn’t need to be smart.
Tootle pip!!
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Why do these otherwise reasonable threads always end up in personal slanging and sledging? It doesn't seem to happen on the non DG forums.
Show some strength - bite your acid tongues and stick with the subject matter.
Show some strength - bite your acid tongues and stick with the subject matter.
The Reverend
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amos2, no mate I dont think I'm out of my depth at all. The last line in my log book states:
Total flying hours: 18,653.47
Total simulator hours ( mainly check and training) 2,804:30
Total flying hours: 18,653.47
Total simulator hours ( mainly check and training) 2,804:30
HSWL
The F111 hit 3 pelicans ( 15 kg ) at 465kts and a 2000 feet. Ejection was initiated and the crew were sadly killed. Not a good case point for airliner op's.
Interesting that only a few years ago, CASA endorsed flying training required an airline trainee to demonstrate a "high speed descent" during line training. This involved entering a five to six thousand foot gate at 20DME at 350kts in a 727, 340kts in a A320 and 320kts in a 737.
I have experience with airlines abroad that do and do not endorse such practices. Those that don't, were concerned about the ability of their crews to manage anything greater than 250kts below 10000 and as an added precaution against CFIT.
I currently fly an aircraft with an VMO of 350kts. No mention is made of birdstrike vulnerabilty, except in the case of windshield heating failure where the 250 below 10000 comes into play. An aircraft is certified to hit a 1.5kg bird anywhere on the aircraft and anywhere within the speed envelope.
Your formula is incomplete, energy is half the birds weight by velocity squared with variables such as bone density, bird speed, bird flight direction and angle of splat!
At 350 kts in a 727 say ( common practice of old ) will hitting a pelican be a catasrophic event?
If it is, perhaps the regulatory authorities and manafacturers have been negligent for a long time.
The F111 hit 3 pelicans ( 15 kg ) at 465kts and a 2000 feet. Ejection was initiated and the crew were sadly killed. Not a good case point for airliner op's.
Interesting that only a few years ago, CASA endorsed flying training required an airline trainee to demonstrate a "high speed descent" during line training. This involved entering a five to six thousand foot gate at 20DME at 350kts in a 727, 340kts in a A320 and 320kts in a 737.
I have experience with airlines abroad that do and do not endorse such practices. Those that don't, were concerned about the ability of their crews to manage anything greater than 250kts below 10000 and as an added precaution against CFIT.
I currently fly an aircraft with an VMO of 350kts. No mention is made of birdstrike vulnerabilty, except in the case of windshield heating failure where the 250 below 10000 comes into play. An aircraft is certified to hit a 1.5kg bird anywhere on the aircraft and anywhere within the speed envelope.
Your formula is incomplete, energy is half the birds weight by velocity squared with variables such as bone density, bird speed, bird flight direction and angle of splat!
At 350 kts in a 727 say ( common practice of old ) will hitting a pelican be a catasrophic event?
If it is, perhaps the regulatory authorities and manafacturers have been negligent for a long time.
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To throw a completely lateral spin on the frozen chicken theory:
Why when the windscreen heat is U/S, is the aircraft speed cautiously reduced, when it is said that whether the chicken is thawed or frozen (i.e. chicken heat U/S) doesn't matter?
Why when the windscreen heat is U/S, is the aircraft speed cautiously reduced, when it is said that whether the chicken is thawed or frozen (i.e. chicken heat U/S) doesn't matter?
PPRuNe Handmaiden
Without the window heat the window is more brittle, therefore it's unable to withstand the same amount of impact force as a heated window. 
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Gday Redo - as I thought.
So does it tf. follow that if the chicken is more brittle (i.e. frozen solid) it is going to provide more impact? (despite the energy equation).
(If I get hit by a hailstone that weighs the same as equivalent water I know which one I withstand easier!)
I think we are getting in to areas of solidity - phases of matter and dissociation. Sorry.
So does it tf. follow that if the chicken is more brittle (i.e. frozen solid) it is going to provide more impact? (despite the energy equation).
(If I get hit by a hailstone that weighs the same as equivalent water I know which one I withstand easier!)
I think we are getting in to areas of solidity - phases of matter and dissociation. Sorry.
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Gnadenburg. Thanks for the excellent reply - I was writing from recollection which is probably not the same as facts as you have shown. Although I am not short of big jet hours and some fighter jet as well, I was surprised to read in your post that CASA demanded demonstration of high speed below 10 descents. As a former member of that esteemed organisation I can say with some truth that they employed some eccentrics in flying ops and insisting on high speed demos - no doubt with a full load of passengers -seems the work of an eccentric to me.
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Airmanship: The ability to operate the aircraft safely and efficiently both in the air and on the ground...
(I think that was the definition they made us sweat on way back...)
Well there's nothing wrong in anyone operating the aircraft exactly as the manuafacturer intended, profile-wise, or in any other respect.
Airmanship was mentioned earlier but operating the aircraft efficiently as well as safely is also a major airmanship consideration, as in the definition quoted above. I have no problem doing this and am able to sleep at night, regarding the safety of my passengers, believe it or not HSWL!!
I observe limitations, as appropriate, including the MEL-dictated speed limit of 250Kt below 10 000ft which is for bird-strike protection when window heat is U/S, as I said before.
The structure of the window material is more flexible when warmer just as many plastics and metals are.
(I think that was the definition they made us sweat on way back...)
Well there's nothing wrong in anyone operating the aircraft exactly as the manuafacturer intended, profile-wise, or in any other respect.
Airmanship was mentioned earlier but operating the aircraft efficiently as well as safely is also a major airmanship consideration, as in the definition quoted above. I have no problem doing this and am able to sleep at night, regarding the safety of my passengers, believe it or not HSWL!!
I observe limitations, as appropriate, including the MEL-dictated speed limit of 250Kt below 10 000ft which is for bird-strike protection when window heat is U/S, as I said before.
The structure of the window material is more flexible when warmer just as many plastics and metals are.
Last edited by itchybum; 4th Jan 2005 at 00:52.
HWSL
You are very much out of the loop reference speed below 10000. I am not surprised though, as a Dick Smith initiative was to remove CASA flying inspectors from the operational seats of airliners.
Until recently, it was SOP for domestic airlines to maintain 300kts below 10000. You were expected to hit and altitude distance gate of 5000 and 20DME. If you did not, flow would be disrupted.
About 10% of the time you would be asked to "make high speed descent". You would hit the gate at anything between 320 & 350KTS. Decelartion would commence from the gate to a stock standard Aussie ILS platform altitude of 3000', followed by a decelerating approach to a stabilisation of about 1000' ( VMC may have been as low as 500' ).
ATC would in some areas ask a high speed descent to 15DME. Many would not deliver in this circumstance.
I have even heard ATC ask an aircraft to : "maintain best subsonic speed to the field, for sequencing". Thankfully a fast jet!
Congestion, STAR arrivals and QF's arrival on domestic sectors begain a noted wane in high speed descents.
If they are not around today, what was the final nail in the coffin?
As earlier mentioned, 250 below 10000' was not common practice in Australia.
You are very much out of the loop reference speed below 10000. I am not surprised though, as a Dick Smith initiative was to remove CASA flying inspectors from the operational seats of airliners.
Until recently, it was SOP for domestic airlines to maintain 300kts below 10000. You were expected to hit and altitude distance gate of 5000 and 20DME. If you did not, flow would be disrupted.
About 10% of the time you would be asked to "make high speed descent". You would hit the gate at anything between 320 & 350KTS. Decelartion would commence from the gate to a stock standard Aussie ILS platform altitude of 3000', followed by a decelerating approach to a stabilisation of about 1000' ( VMC may have been as low as 500' ).
ATC would in some areas ask a high speed descent to 15DME. Many would not deliver in this circumstance.
I have even heard ATC ask an aircraft to : "maintain best subsonic speed to the field, for sequencing". Thankfully a fast jet!
Congestion, STAR arrivals and QF's arrival on domestic sectors begain a noted wane in high speed descents.
If they are not around today, what was the final nail in the coffin?
As earlier mentioned, 250 below 10000' was not common practice in Australia.
Moderate, Modest & Mild.
As earlier mentioned, 250 below 10000' was not common practice in Australia.
As Gardenbug stated, it was standard practice until then (1989) to close the throttles at TOD, hit 5,000' at 20nm to run, and commence a speed bleed, to be (landing) configured at 1,000' - 1,500'.
THE most fuel efficient AND time efficient descent yet devised - but one that required more monitoring and a closer involvement by the pilots, than the "dumbed down" 250 below 10 "light aircraft mindset".
In a similar vein, I have found Aussie ATC'ers to be a lot more flexible in their ability and willingness, to re-sequence arriving (and occasionally departing) aircraft.
Keep up the good work chaps and chapesses