Heathrow steep approach trials
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The approach concept that is being connected with Emirates is a vertically segmented approach which would still be a three degree GP inside 5-6nm from touchdown, so it's a completely different animal than a complete GP angle change.
Quite a few airports around Europe are looking at this type of approach for noise mitigation.
Quite a few airports around Europe are looking at this type of approach for noise mitigation.
Just a vague recollection that when City originally opened, the approach glidepath was 2 - segment initially 10 or 11 deg becoming 3 deg at about 1 mile. This however was for obstacle clearance rather than noise mitigation.
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5.5° GPA on final to 5nm with the A380 is lemming talk.
Coming off from those speeds at that angle and trying to manage that amount of energy is just going to lead to unstablilized approach issues. Maintaining a tight multi-variant queue will end up leading to loss of sep beacuse it will be just too difficult.
Many of the others, that are real slick like the 737-8 and 9's are going to be throwing up the speed brakes.
The A380 is pretty damn quiet, as are many of the other Airbus variants, while Boeing has some real screamers.
There is a wake class, perhaps if there was a noise class (based on the Engine model sound, not the weight) things would start to evolve a bit better, and tere would not be the need for this crazy GPA stuff.
Coming off from those speeds at that angle and trying to manage that amount of energy is just going to lead to unstablilized approach issues. Maintaining a tight multi-variant queue will end up leading to loss of sep beacuse it will be just too difficult.
Many of the others, that are real slick like the 737-8 and 9's are going to be throwing up the speed brakes.
The A380 is pretty damn quiet, as are many of the other Airbus variants, while Boeing has some real screamers.
There is a wake class, perhaps if there was a noise class (based on the Engine model sound, not the weight) things would start to evolve a bit better, and tere would not be the need for this crazy GPA stuff.
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5.5° GPA on final to 5nm with the A380 is lemming talk.
Emirates have argued that they can begin their descent at 5.5 degrees, before moving to a 3 degree approach for the last section. Although the idea is worth exploring further, one senior pilot commented to me that "with enough training I think I could land a plane like that without loss of life 98 times out of 100"
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If they want to do a 3.2degree slope trail, why not just wait until its hot.
Switch off the ILS/MLS->RNAV approaches only for the day and measure the noise... Nil cost.
Switch off the ILS/MLS->RNAV approaches only for the day and measure the noise... Nil cost.
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The Frankfurt experience was reported at ICANA.
The 3.2 degree approach :
ICANA 2013: Experience with the steeper approach angle of 3.2 degrees - YouTube
Is the amount of work worth the limited effect ? the audience asks. The rigid adherence to CDA giving rise to noisier approaches was interesting.
The multi-segment 4.49 degree approach trial :
ICANA 2013: Steeper Approach -- a research project of DLR and Airport and Region Forum - YouTube
The 3.2 degree approach :
ICANA 2013: Experience with the steeper approach angle of 3.2 degrees - YouTube
Is the amount of work worth the limited effect ? the audience asks. The rigid adherence to CDA giving rise to noisier approaches was interesting.
The multi-segment 4.49 degree approach trial :
ICANA 2013: Steeper Approach -- a research project of DLR and Airport and Region Forum - YouTube
Re: “… after all, the autopilot will fly the GP whatever angle it is”. (#3)
Not necessarily so. Some auto-flight systems might schedule glideslope control gains with altitude or configuration, which could alter the relationship between alt/range or time-duration on steeper approaches. Also a steeper glideslope beam may have a different sensitivity than that at 3deg – constant beam width at higher angle has a different vertical spread. Don’t forget other systems e.g. EGPWS.
The aircraft certification (for GS > 4.5 deg) may require a specific configuration or procedure, but most aircraft should be able to fly 3.5 deg without systems modification.
The BAe146/Avro RJ AFM has a chart of noise benefit against approach angle. These aircraft demonstrated Cat 2 tracking accuracy at LCY as part of their certification (LCY GS is Cat 2 equivalent), but the authorities mistakenly insisted on greater visibility requirements, even though a steeper approach provides a better over-the-nose view.
LCY has always been a constant angle approach.
RAE trials (1970s) demonstrated two segment approaches and autolands to Cat 3 standards for BAc1-11 sized aircraft and considered the feasibility for larger types such as the Tristar. A 6 deg to 3 deg changeover required a corner point at approx 1000ft (2nm @ 6 deg) to enable the final approach to be sufficiently stable.
MLS trials demonstrated two-stage segmented and offset (curved path) approaches which have additional noise reduction benefits. Some work was also done on intermixing normal approaches with steep approach capable aircraft, which used an alternative GS beam to land further into the runway with significant noise benefit and increased traffic landing rates due to wake turbulence avoidance.
Not necessarily so. Some auto-flight systems might schedule glideslope control gains with altitude or configuration, which could alter the relationship between alt/range or time-duration on steeper approaches. Also a steeper glideslope beam may have a different sensitivity than that at 3deg – constant beam width at higher angle has a different vertical spread. Don’t forget other systems e.g. EGPWS.
The aircraft certification (for GS > 4.5 deg) may require a specific configuration or procedure, but most aircraft should be able to fly 3.5 deg without systems modification.
The BAe146/Avro RJ AFM has a chart of noise benefit against approach angle. These aircraft demonstrated Cat 2 tracking accuracy at LCY as part of their certification (LCY GS is Cat 2 equivalent), but the authorities mistakenly insisted on greater visibility requirements, even though a steeper approach provides a better over-the-nose view.
LCY has always been a constant angle approach.
RAE trials (1970s) demonstrated two segment approaches and autolands to Cat 3 standards for BAc1-11 sized aircraft and considered the feasibility for larger types such as the Tristar. A 6 deg to 3 deg changeover required a corner point at approx 1000ft (2nm @ 6 deg) to enable the final approach to be sufficiently stable.
MLS trials demonstrated two-stage segmented and offset (curved path) approaches which have additional noise reduction benefits. Some work was also done on intermixing normal approaches with steep approach capable aircraft, which used an alternative GS beam to land further into the runway with significant noise benefit and increased traffic landing rates due to wake turbulence avoidance.
