EGT spread LOP vs ROP

Any DA40 related topics

Moderators: Rick, Lance Murray

User avatar
Rich
5 Diamonds Member
5 Diamonds Member
Posts: 4592
Joined: Mon Aug 30, 2010 12:40 pm
First Name: Rich
Aircraft Type: DA40
Aircraft Registration: N40XE
Airports: S39 Prineville OR
Has thanked: 145 times
Been thanked: 1180 times

Re: EGT spread LOP vs ROP

Post by Rich »

chocolatecake wrote: Fri Aug 05, 2022 4:40 am Lean was on the way there, rich on the way back. Roughly 2 hours apart and same altitude.
Time in service? What does that mean, then?
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
User avatar
Rich
5 Diamonds Member
5 Diamonds Member
Posts: 4592
Joined: Mon Aug 30, 2010 12:40 pm
First Name: Rich
Aircraft Type: DA40
Aircraft Registration: N40XE
Airports: S39 Prineville OR
Has thanked: 145 times
Been thanked: 1180 times

Re: EGT spread LOP vs ROP

Post by Rich »

Rich wrote: Fri Aug 05, 2022 4:44 am
chocolatecake wrote: Fri Aug 05, 2022 4:40 am Lean was on the way there, rich on the way back. Roughly 2 hours apart and same altitude.
Time in service? What does that mean, then?
Sorry. That sounds kind of snarky. But it looks like the second screen is like 6.5 flight hours later and likely a different day and on a kind of long flight.
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
User avatar
chocolatecake
2 Diamonds Member
2 Diamonds Member
Posts: 26
Joined: Fri Jan 07, 2022 6:24 pm
First Name: Scott
Aircraft Type: DA40
Aircraft Registration: N238DC
Airports: KBFI
Has thanked: 8 times
Been thanked: 4 times

Re: EGT spread LOP vs ROP

Post by chocolatecake »

Rich wrote: Fri Aug 05, 2022 5:25 am
Rich wrote: Fri Aug 05, 2022 4:44 am
chocolatecake wrote: Fri Aug 05, 2022 4:40 am Lean was on the way there, rich on the way back. Roughly 2 hours apart and same altitude.
Time in service? What does that mean, then?
Sorry. That sounds kind of snarky. But it looks like the second screen is like 6.5 flight hours later and likely a different day and on a kind of long flight.
Oh lol, you are right. The pic of the MFD is in fact from a previous day, the one I took that day turned out blurry so I used an earlier one just to illustrate the kinda EGT stepdown pattern that is always there. The flight logs are from the same day though.
User avatar
Rich
5 Diamonds Member
5 Diamonds Member
Posts: 4592
Joined: Mon Aug 30, 2010 12:40 pm
First Name: Rich
Aircraft Type: DA40
Aircraft Registration: N40XE
Airports: S39 Prineville OR
Has thanked: 145 times
Been thanked: 1180 times

Re: EGT spread LOP vs ROP

Post by Rich »

The very close balance among cylinders suggests you don't have a problem to worry much about. But the non-correspondence and severe variation among the EGTs makes me think there is a problem in the EGT thermocouples or their wiring. Keep in mind the variation between 1400 and 1500 degF for type K thermocouples is a couple of microvolts. In addition I've seen deposits build up on these probes where it's hard to remove them from the exhaust. Some variation is to be expected in the actual EGTs but your indications (1 and 4) stretch credulity.
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
User avatar
Charles
5 Diamonds Member
5 Diamonds Member
Posts: 638
Joined: Thu Aug 26, 2010 5:36 pm
First Name: Charles
Aircraft Type: DA40
Aircraft Registration: C-FLEV
Airports: CYHU
Has thanked: 27 times
Been thanked: 96 times

Re: EGT spread LOP vs ROP

Post by Charles »

I wouldn't worry about it. Quoting Busch:
The absolute value of EGT is not important. It is quite common for different cylinders of the same engine to indicate quite different EGTs, and that’s perfectly normal. What’s important is the relative value of EGT for a particular cylinder compared to that cylinder’s peak EGT value. In other words, we really don’t care whether a cylinder’s EGT is 1390°F or 1460°F – what we care about is whether the cylinder’s EGT is 80°F ROP or 30°F LOP.
Source: https://resources.savvyaviation.com/und ... and-egt-2/
Post Reply