This is exactly what I explain when asked or converse with the person next to me when the topic comes up.

 

Good discussion.
Also, the difference between Z Weight and Max Landing Weight in the 737 is:
737-700 7500lbs
737-800 8000lbs
737-900ER 10000lbs
8Max 7400lbs
9Max 9400lbs
That means unless you were Takeoff weight limited, you can land with that much fuel in your tanks without bumping anything.

 

That's actually a smart way to look at things. I never thought about it like that. You learn something everyday 😂

 

Yeah, that never happened. Isolated airports like Vegas have high contingency fuel requirements. And again, every Delta flight without an alternate gets 70 minutes of fuel. You get 45 minutes of reserve, and 25 minutes of contingency at a minimum!

 

Recent example.


You arrive into SAN with 7.0 and Approach holds you at the FAF to allow 2 opposite-direction departures out. That will take 8 minutes/700 lbs. Your alternate is ONT and the burn from SAN to ONT is 1.4. According to that instructor, you should divert to ONT now. That would have me land into ONT with 5.6.

Or I could hold, and start the approach with 6.3. Maybe I have to go around. That means I could get to ONT with 4.6. Sorry, but holding for 8 minutes is much easier than dealing with a divert during a simple day trip. Even if another unforeseen event happened that forced a diver to ONT, I still could have landed with 52 minutes of fuel. And if I didn't like how ATC was getting me to ONT, then declare min fuel. There are a lot of backup options if plan A doesn't work.

And before anyone doubts the alternate fuel burns, Delta started using the preferred ATC routings and realistic altitudes to alternates rather than straight-line distances.

 

Was the instructor saying any time you are estimated to land under 6 you should immediately divert? I know I wasn't there but I find that highly improbable. How it's always been explained to me is that 6.0 is purely for planning purposes at the gate.

 

Thats exactly how it was explained, from an at the gate planning perspective I have my number whatever it may be. Once were airborne we evaluate and adjust.

 

Exactly. According to a flight plan once I had 45 minutes of holding fuel (was expected). But then ATC dropped me from mid-30s to low 20s for holding. That 45 became 25 in a hurry. Always evaluating.

 

They exact question was what is the minimum amount of fuel you would feel comfortable landing with. And as I am have trying to say, there is no simple answer for that. The context of the actual flight is will dictate the answer. There response was, "You should always plan to land with at least 6.0."

And the context for this specific lesson was stating an approach with 5.5 and having to go around due to a runway closure. I elected to take a visual approach to another runway instead of diverting.

 

If you're at Delta, the 45 minutes of fuel reserve on the flight plan is calculated at 1,500 feet above the destination. If you only had 45 minutes of reserve at cruise altitude, you were way below your flight planned reserve fuel value.