A related question....

Is it a regulatory requirement to use an autopilot to fly a RNAV approach to LNAV/VNAV minima?

No, is the answer.

Can someone refresh my knowledge (or not ) , on two set of Minima for the same LNAV approach in this procedure ?


https://cimg5.ibsrv.net/gimg/pprune....5f86ae229.jpeg

Hi Nick
The higher limit is based on an obstacle in the missed approach procedure and because at the standard assumed climb gradient that obstacle will not be cleared by the required minima the minimum descent altitude has to be raised from the minima calculated for the final approach sector on its own. However, if an aircraft can climb at 4.3% the the obstacle can be cleared from the lower minimum descent altitude. An MDA(H) has to be published based on the standard climb gradient.
Cheers
TeeS

Ahhhh…..yes . I’m an idiot . Thanks TeeS.

ICAO DOC 8168 (Flight Procedures) refers. The certification missed approach climb gradient is 2.1% for a twin jet. Most procedures are based on a missed approach climb gradient of 2.5% and produce the minima of 940ft from your chart to clear obstacles. If the aircraft can achieve a higher missed approach climb gradient then lower published minima can be achieved (670ft in your example at 4.3% gradient). The achievable gradient depends on temperature, airfield altitude land flap setting and aircraft weight. As an example, the 737 NG 27K engines and short field performance package can achieve about 3.2% at 78 tonnes (typical max T/O Weight) at a sea level airfield and 30 degrees C using flap 30 for landing. At 30 degrees,1000ft airfield elevation and a typical max landing weight of 65 tonnes with flap 30 it can achieve around 5.3% and so could comfortably use your lower minima. This would be a consideration when, for example, considering tankering fuel to a destination with poor weather, as the higher landing weight might not allow the use of the lower minima to increase the chance of a successful approach. From memory, an example would be the Runway 01R ILS minima at Dalaman in Turkey (LTBS) which give minima of around 850 feet for 2.5% missed approach gradient and 210 feet for 5% as you can start the missed approach from closer to obstacles with the better gradient. Lower land flap settings (flap 30 instead of flap 40 on the 737) give better gradients due to the higher approach speed, and further improvements can be achieved with bleeds off for landing.

Every question asked should trigger other thoughts (idiots rarely ask questions).

If lesser performance aircraft, higher DH, were required to fly a GA from below DH, i.e. a rejected landing (baulked landing), the ICAO doc appears to assume all engines operative, but also knowledge of procedural routing for engine failure after takeoff.

Is this correct ?

ICAO Doc 10064 - Aeroplane Performance Manual Page 27-28

https://www.sapoe.org/wp-content/upl...rce.pdf#page60

“A distinction needs to be made between a missed approach and a rejected landing. A one-engine-inoperative missed approach from the minimum descent altitude (height) (MDA (H)), decision altitude (height) (DA (H)), or above can frequently be flown following the published missed approach procedure. A rejected landing from a lower altitude may require some other procedure (e.g., following the same one-engine-inoperative procedure as used for take-off). In any case, the pilot should be advised of the appropriate course of action when the published missed approach procedure cannot be safely executed.”

IIRC, the 2.5% starts at the Mapt for Terps and for PANSOPS at the MDA longitudinally 15 seconds at your max category speed further along the runway. If you’re below MDA, you’re below profile, and you’ll need more than 2.5 to get back above, if you don’t hit anything first. You should go another way. Like your EO SID.

This is a concept that many pilots are not aware of , flying the missed approach below the MDA thinking to be on the safe side , not always true.
Thank you gents .