What’s the difference?<\/h4>\n
Seems a good question to answer first.<\/p>\n
There are generally three types of descent<\/strong> you can expect when you head into a big, controlled airport.<\/p>\n The Step Down<\/strong> is exactly what it sounds like – you descend, level off, maintain that for a bit, then descend again, level off again, maintain it for a bit again…<\/p>\n This generally sucks for three reasons. One it is annoying for pilots because it means you have to do more. Two it can be a lot noisier on the ground if airplanes are roaring along low level, at lower speeds and three it is obviously a lot less fuel efficient.<\/strong><\/p>\n Next up, you have the CDA<\/strong> – the constant descent approach. Again, exactly what it sounds like. (I feel like I don’t really need to explain this to pilots reading this but who knows, maybe a non-pilot has taken a random interest in it because of the excellent picture I used for the header).<\/em><\/p>\n So, with a CDA ATC, or the pilot, attempts to continue descending without levelling off. This is better for the reasons already stated above, but it is not the best because a CDA can mean descending with thrust on. A good example is EGLL\/London Heathrow<\/strong> who still consider it a CDA if you’ve descend more than 50 feet in 2nm, and don’t have a level segment of more than 2.5nm below 6000′.<\/p>\n This acronym stands for ‘optimised profile descent’.<\/strong> Sorry, optimized (because its an American name so I’ll give it the ‘z’).<\/p>\n Not to be confused with ODP (Obstacle Departure Procedures)<\/strong>. I feel like we may have reached a point in aviation where every acronym possible has been used.<\/p>\n\n
![\"\"](\"https:\/\/ops.group\/blog\/wp-content\/uploads\/2023\/02\/EGLL-CDA-1024x440.png\")
<\/h4>\nWhich brings us to the OPD.<\/h4>\n
![\"\"](\"https:\/\/ops.group\/blog\/wp-content\/uploads\/2023\/02\/Pointless-descent-diagrma-1024x708.png\")