Missed Approach Gradient
Thread Starter
Missed Approach Gradient
Ok guys,
nice easy one for my first post... I would say long time listener first time caller but I think thats gay............dammit.
Missed Approach Gradients
2.5% for climb out.
But if you are on sinigle engine, assuming in a twin, and your climb out performance will only give you say 1.9% you have to increase MDA in order to climb at 1.9% and still make the 2.5% climb.
So how do you the math to find the increased MDA. I am not that gifted in math-at least not tonight, having a major brain fart on this one and too tired to poo it out.
Sorry for saying poo. But we are all grown ups...no wait, pilots..sorry.
nice easy one for my first post... I would say long time listener first time caller but I think thats gay............dammit.
Missed Approach Gradients
2.5% for climb out.
But if you are on sinigle engine, assuming in a twin, and your climb out performance will only give you say 1.9% you have to increase MDA in order to climb at 1.9% and still make the 2.5% climb.
So how do you the math to find the increased MDA. I am not that gifted in math-at least not tonight, having a major brain fart on this one and too tired to poo it out.
Sorry for saying poo. But we are all grown ups...no wait, pilots..sorry.
Join Date: Jan 1999
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Hi,
the following is a summary taken from Trevor Thom's "The Instrument Rating Manual Vol. 2 - 1991"
Prior to flight consult the POH to determine what rate of climb is likely in the asymmetric condition. Eg: 190 feet per minute. Also consider what the likely groundspeed asymmetric is going to be. Eg: 100 knots. A rule of thumb to work out gradient is RoC/GS = Gradient eg: 190/100 = 1.9%
Now get your nav computer and set 19 on the outer scale over 25 on the inner scale (1.9% over 2.5%). Then find out how far you have to climb for the missed approach on the inner scale. Eg: 1500 feet. The number opposite is what is possible at the reduced gradient. Eg 1200 feet.
The difference between the two is what you should increase the MDA by to achieve the reduced gradient in the asymmetric condition. Eg: add 300 feet to the MDA.
Hope this helps
Tinkicka
the following is a summary taken from Trevor Thom's "The Instrument Rating Manual Vol. 2 - 1991"
Prior to flight consult the POH to determine what rate of climb is likely in the asymmetric condition. Eg: 190 feet per minute. Also consider what the likely groundspeed asymmetric is going to be. Eg: 100 knots. A rule of thumb to work out gradient is RoC/GS = Gradient eg: 190/100 = 1.9%
Now get your nav computer and set 19 on the outer scale over 25 on the inner scale (1.9% over 2.5%). Then find out how far you have to climb for the missed approach on the inner scale. Eg: 1500 feet. The number opposite is what is possible at the reduced gradient. Eg 1200 feet.
The difference between the two is what you should increase the MDA by to achieve the reduced gradient in the asymmetric condition. Eg: add 300 feet to the MDA.
Hope this helps
Tinkicka
Thread Starter
alpha
take a small twin engine plane, say a twin cammanche. Place it at a higher altitude airport, say Armidale and fly on a normal hot day- 28+ degrees. I know for a fact it has trouble even getting over 1% in cruise if you lose an engine. So it may be worth knowing it as you can control the MDA and thus your safety and the rules where you cannot control the ambient conditions or ask the strip to go to sea level to allow a better climb out performance.
Thanks for your thoughts so, just maybe here is some more thoughts for you.
Regards
take a small twin engine plane, say a twin cammanche. Place it at a higher altitude airport, say Armidale and fly on a normal hot day- 28+ degrees. I know for a fact it has trouble even getting over 1% in cruise if you lose an engine. So it may be worth knowing it as you can control the MDA and thus your safety and the rules where you cannot control the ambient conditions or ask the strip to go to sea level to allow a better climb out performance.
Thanks for your thoughts so, just maybe here is some more thoughts for you.
Regards
Further to Tin Kickers response. Yes add the 300 feet. For this example lets say we have a new MDA of 900 feet. If the engine failure occurs above 900 feet prior to the MAPT continue your descent to 900 feet. If the engine failure occurs below 900 feet prior to the MAPT then you should start climbing immediately to get back to 900 feet by the MAPT. Then at the MAPT you should achieve the required obstacle clearance. A level segment at 900 feet prior to the MAPT may increase your chance of getting in. It would be prudent not to even attempt the approach on one engine if weather conditions indicated a single engine approach was not going to be successful. Much more prudent to divert somewhere more suitable from a safe height. Cheers.
