Another airport being ruined by rich bastards
The Approach Gradient used depends on a number of factors. RWY code, Instrument or not, Precision or not. The CBR master plan says that sometime in the last 20 years, RWY12/30 was reclassified (I'm assuming an improvement) to a Code 2B RWY. I don't have any idea what it was prior. Code 1 non-instrument RWYs have an approach gradient of 5% (For comparison, Code 1 instrument non-precision is 3.3% and precision is 2.5%). Code 2 NI should be 4%. Perhaps that is why 30 is said to use 5% now, because they couldn't meet the 4% when they reclassified it, or that is why the Threshold was displaced a few metres and still used 5%. Who knows what was involved in the reclassification.
The gradient is measured from 60m prior to the threshold, at the same elevation and splays out 10 degrees either side of the RWY strip, There should be no obstacle penetrating through it. If there is, the start of the gradient is moved until there is no intrusion, 60m is added, and there is your threshold. If you already have a threshold, and there is a new obstacle that penetrates and cannot be removed, then the threshold is displaced to compensate, leaving the existing RWY still behind it for take offs in the same direction and takeoffs and landings from the other direction.
If you fly the gradient to the threshold you will pass over the obstacle (if there is one) due to the 60m built in. It's also why the painted aiming points are further down the runway so that there is always a margin for error in the approach.
Like I said don't write about things you don't know about. Pilots legally fly less than a 5% gradient and with a surveyed flight path every day in complete safety and without the need to use any special technique. Pilots will refer to a document more relevant to them i.e. Jepps or equivalent. Have a look at the gradient required for the RNP approach then checkout the gradient using the PAPI for slope guidance. Hint not 5%
So CBR RWY30 RNP uses a 3.7 degree approach path. The PAPI uses 3.9 Degrees. 3.7 degrees angle is 6.5% gradient. 3.9 degrees is 6.8% gradient. You are right, you are not flying 5%, but you are certainly not flying less than it.
A 5% gradient is about 2.9 degrees. Probably why ILS glide paths are set to 3 degrees. The approach gradients to ILS runways are surveyed at 2% which is about 1.1 degrees, so flying the glidepath will keep you well above any obstacles.
A 5% gradient is about 2.9 degrees. Probably why ILS glide paths are set to 3 degrees. The approach gradients to ILS runways are surveyed at 2% which is about 1.1 degrees, so flying the glidepath will keep you well above any obstacles.
Here's Australian Flying's summary of the issue: Consultation Session raises Fears for GA at Canberra - Australian Flying
There is a lot of "car parking" to the north and north east of the threshold. Coincidentally enough, 450m ends up just to the SE of the Beaufighter Street parking area, a surprisingly large parking area for what?
Here's Australian Flying's summary of the issue: Consultation Session raises Fears for GA at Canberra - Australian Flying
But hang on a sec'. Apparently runway 12 "has been used on average less than once a day for the past four years" and "the only aircraft that use Runway 12 for landing are light GA aircraft less than 5700 kg."
Let's assume that's all true. And let's set aside the fact that aircraft "use" the runway they're told by ATC to use and any out-of-tower hours use would be unknown to Airservices.
It follows that - on CAG's own logic - the "safety" issue is caused by one light aircraft flying an approach on average less than once a day. One light aircraft. Less than once a day. And that's the "safety" basis for displacing the threshold.
What sickens me most about the dismantling of GA infrastructure in the interests of private profits these days is the carefree arrogance of the bull**** justifications for it. But why wouldn't they be arrogant? They're allowed to get away with it.
