Da40ng useful load vs max takeoff/max landing load

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hifiaudio2
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Da40ng useful load vs max takeoff/max landing load

Post by hifiaudio2 »

The DA-40NG that I just picked up that has air conditioning states a useful load of about 750 lb with no fuel. The POH also states a max landing load of about 2680 versus max takeoff of 2880. Give or take a few pounds on both. Does this mean that the max landing useful load is also 200 lb less? So only about 550 lb? Before fuel? That seems like an almost unusable plane for more than one person with full fuel if that is true. At about 260 lb for fuel that would only leave 290 lb for all people and cargo. Can someone help me understand these numbers? I was calculating 750 lb useful load when looking into this plane the whole time, not 550 lb. This was brought up by the flight school We are leasing back to so I'm assuming we are all just missing something or misunderstanding how the terms are related.
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Rich
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Re: Da40ng useful load vs max takeoff/max landing load

Post by Rich »

1. Double-check the max landing mass for your aircraft. There's a mod listed as MAM 40-574 which increases the max landing and max zero fuel mass to 2822 and 2789, respectively. It's unclear what this mod is, but a 2888 MTOW and 2681 max landing mass doesn't make sense. There's a similar pairing of OSB's for the Lycoming versions, where the MTOW mod requires the MLW mod. I don't know for sure but 40-574 is likely related to Landing Gear.

2. The presumption is you're not landing with full fuel.

NOTE: Don't confuse useful load with payload (essentially cabin load).
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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hifiaudio2
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Re: Da40ng useful load vs max takeoff/max landing load

Post by hifiaudio2 »

Okay thank you I will check for that mod. And yeah I do figure that everyone would assume you aren't landing with full fuel but heck even an hour of flying would only burn about 40 lb of fuel. I wouldn't think that there would be a rule that you better fly for two or three hours or don't land lol. Definitely need to get to the bottom of it though since this will be landed quite a bit with two people in it at least all the time except for some rare solos.
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Rich
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Re: Da40ng useful load vs max takeoff/max landing load

Post by Rich »

I agree with a wide disparity between MTOW and MLW being a problem. Here’s a case study of the original DA40:

MTOW 2535, MLW 2407 = 129 lb of fuel difference.

The OSB’s available for the plane:

MLW/max ZFW: 2535
MTOW: 2646. This OSB specifies that the MLW mod is required, so 2646-2535 = 111 lb fuel difference.

Consider what doing the MTOW without MLW mod would mean: 2646-2407= 241 lb, which is the entire fuel capacity of my plane :shock:

That’s why I think those two DA40NG modifications go together.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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hifiaudio2
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Re: Da40ng useful load vs max takeoff/max landing load

Post by hifiaudio2 »

So if I I'm reading around the forum and internet, a MAM is a design change after a certain date or serial number? So it's possible that my plane has to already have it? If I'm after that date.... Which I don't know what the date or serial number delineation is for this one...
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Re: Da40ng useful load vs max takeoff/max landing load

Post by dant »

Your POH has a list of MAMs in the front in the first couple pages, and check marks as to which ones you have.
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hifiaudio2
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Re: Da40ng useful load vs max takeoff/max landing load

Post by hifiaudio2 »

Well here is what I got from Diamond tech support on the matter, in case it helps others with Canadian built Da40 NGs:

"Although it does not directly reference in the POH of what your max landing weight is, MAM 40-574 is already incorporated into your aircraft.
I have been looking into the paper trail - Diamond Canada did not start producing 40NG aircraft until 2017, so the MAM listed was originally meant for only Austrian made 40NG's. All MAM's that were approved for Austrian 40NG's were then incorporated into Canadian made 40NG's starting at 40.NC001."
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Re: Da40ng useful load vs max takeoff/max landing load

Post by ScottOHare »

Just remember if you take off at max weight you have to burn off 52 lbs of fuel which is over an hour of flight time at 75% power. My 2019 DA40 NG - without AC - has a useful load of 864 lbs, but with full fuel and two guys in the front needs 20 lbs of ballast in the back to keep within the CG forward limit.
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Re: Da40ng useful load vs max takeoff/max landing load

Post by Rich »

ScottOHare wrote: Tue Jun 14, 2022 2:45 pm Just remember if you take off at max weight you have to burn off 52 lbs of fuel which is over an hour of flight time at 75% power. My 2019 DA40 NG - without AC - has a useful load of 864 lbs, but with full fuel and two guys in the front needs 20 lbs of ballast in the back to keep within the CG forward limit.
All DA40's have a limitation like this. Worst is the original 2535/2407 situation, where if you departed at MTOW (a big if) you'd have to burn off just over 21 gallons of fuel. But both the Lycoming and NG flight manuals have procedures for landing above the MLW. (For the NG see 4B.7). The presence of these procedures gives you cover with insurance/FAA, etc. Should there be a problem.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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hifiaudio2
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Re: Da40ng useful load vs max takeoff/max landing load

Post by hifiaudio2 »

It turns out that my aircraft came with a document listing what was incorporated into the plane that did NOT list MAM 40-574. Diamond still swears it's on there, and has agreed to pay for a mechanic with inspection authority to examine the area, certify that it's present, and update/sign my AFM.
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