Vietnam B789 at Munich on Aug 15th 2026, late rotation, tailstrike, runway overrun, tyre damage

[BobDDuck]

So I've been out of the big-plane game for a while now (11+ years?!? That long?!? Oye!) but I guess most of the big jet operators don't have any sort of acceleration check or similar? Back in the day (apparently WAY back in the day) if Freddy was heavy enough (or runway short enough) and we had to do a standing take-off, we would calculate a acceleration check. Basically after XX seconds after brake release you needed to be at XXX airspeed or well, RTO.

This was used in addition to the normal V1/V2 and all, but a good way to make sure you were going fast enough. I know this was the way with the legacy (TF-39) jets but I don't remember if it carried over the the CF6s.

We don't have one as policy, other than the normal Airbus 100 knots callout (for verifying all three speed tapes are about the same). I've got a series of rough estimates in my head based on weight and FLEX temp for time to reach 80 knots.

 

[///AMG]

So I've been out of the big-plane game for a while now (11+ years?!? That long?!? Oye!) but I guess most of the big jet operators don't have any sort of acceleration check or similar? Back in the day (apparently WAY back in the day) if Freddy was heavy enough (or runway short enough) and we had to do a standing take-off, we would calculate a acceleration check. Basically after XX seconds after brake release you needed to be at XXX airspeed or well, RTO.

This was used in addition to the normal V1/V2 and all, but a good way to make sure you were going fast enough. I know this was the way with the legacy (TF-39) jets but I don't remember if it carried over the the CF6s.

Last time I remember doing an accel check was in the T-45 in flight school. I think it was a set distance, and the calculation was the speed you should be at the corresponding distance marker. Haven't seen it since though

 

[DE727UPS]

It's that something. Such a simple thing to check speed at a given point. Never heard of it before. Not a bad idea and not a hard thing to figure out.

 

[Cherokee_Cruiser]

On the 737 about 80% of the time you’ll hit 80 kts passing the 1000 ft white paint markers. Definitely by 1,500 ft marker.



General rule of thumb applies. 2/3 of rotation speed by half way down the runway. Eg, 165 knot rotation. You should be 110 knots at least by half way down the runway.

 

[MikeD]

Last time I remember doing an accel check was in the T-45 in flight school. I think it was a set distance, and the calculation was the speed you should be at the corresponding distance marker. Haven't seen it since though

It's that something. Such a simple thing to check speed at a given point. Never heard of it before. Not a bad idea and not a hard thing to figure out.

we had it in the T-38, A-10 and F-117. in the two former ones, it was a chart we manually ran during preflight planning prior to brief. in the latter, it was a computer program output.

In the takeoff data section of the card below. below, it shows as ACS, or Accel Check Speed. Along with rotation speed, takeoff/liftoff speed. single engine, T/O distance, and max abort speeds.

 

[///AMG]

we had it in the T-38, A-10 and F-117. in the two former ones, it was a chart we manually ran during preflight planning prior to brief. in the latter, it was a computer program output.

In the takeoff data section of the card below. below, it shows as ACS, or Accel Check Speed. Along with rotation speed, takeoff/liftoff speed. single engine, T/O distance, and max abort speeds.

View attachment 90591

Hah those are some legit rotation/TO numbers. Makes sense given the apparent aerodynamics of the airplane, or lack thereof Also I think a line speed check for us really wouldn't make sense, normal takeoff is like a 1800-2000' TOD/roll. Rather than almost 7000! I think maybe the longest I've seen it, with a bunch of bombs in Fallon at high elevation on a hot day, was perhaps 3500-4000'? But our low speed/high speed cutoff used to be 100 knots. It has more recently evolved to "airspeed alive" which is right around 50 knots. By then, you have traveled like 12 feet down the runway

 

[MikeD]

Hah those are some legit rotation/TO numbers. Makes sense given the apparent aerodynamics of the airplane, or lack thereof Also I think a line speed check for us really wouldn't make sense, normal takeoff is like a 1800-2000' TOD/roll. Rather than almost 7000! I think maybe the longest I've seen it, with a bunch of bombs in Fallon at high elevation on a hot day, was perhaps 3500-4000'? But our low speed/high speed cutoff used to be 100 knots. It has more recently evolved to "airspeed alive" which is right around 50 knots. By then, you have traveled like 12 feet down the runway

longest i’ve seen on fully loaded 52.5k weight jet was an 8200’ takeoff roll, takeoff speed of 200kts. The jet has a permanent 68 degree wing sweep and no lift devices at all; no leading edge or trailing edge flaps, no slats, no speedbrakes. Hence the above numbers.

 

[///AMG]

longest i’ve seen on fully loaded 52.5k weight jet was an 8200’ takeoff roll, takeoff speed of 200kts. The jet has a permanent 68 degree wing sweep and no lift devices at all; no leading edge or trailing edge flaps, no slats, no speedbrakes. Hence the above numbers.

Interesting, that jet was pretty light apparently. Our ramp weight with a single centerline, full gas, and nothing else, is right around 52k and some change. Maybe not the absolute heaviest load nowadays with all these crazy ass A/A missiles we are getting that are enormous, but the 5-wet tanker was a 66k GW. I'm not sure what takeoff roll or speed is for that, since it is a carrier-only configuration, but the catapult end-speed was something like 176 knots.

 

[MikeD]

Interesting, that jet was pretty light apparently. Our ramp weight with a single centerline, full gas, and nothing else, is right around 52k and some change. Maybe not the absolute heaviest load nowadays with all these crazy ass A/A missiles we are getting that are enormous, but the 5-wet tanker was a 66k GW. I'm not sure what takeoff roll or speed is for that, since it is a carrier-only configuration, but the catapult end-speed was something like 176 knots.

117 is 29.5k empty weight. 19k of full internal fuel and 2 x Mk84 / GBU-10/10I, puts it at 52.5k. it just needs airflow over the wings to takeoff, with no other assistance. Hence we had a 10k runway length minimum. Hence our main ops bases at TNX with 12k; and HMN with three runways of 15.2k, 14.1k, and 11.5k

 

[///AMG]

117 is 29.5k empty weight. 19k of full internal fuel and 2 x Mk84 / GBU-10/10I, puts it at 52.5k. it just needs airflow over the wings to takeoff, with no other assistance. Hence we had a 10k runway length minimum. Hence our main ops bases at TNX with 12k; and HMN with three runways of 15.2k, 14.1k, and 11.5k

Certainly not uncommon amongst LO aircraft, but 19k internal is quite respectable for a modern tactical aircraft. I think the F-35C is somewhere around 18k and some change. Not sure about F-22, but I imagine it has plenty. As a contrast, the legacy Hornet was around 9.5k internal, and the F-16 was IIRC 7.2? Lol

 

[DPApilot]

I think we had the same student!🫩

As a previous OE instructor on two different fleet types during my career I feel like I saw everything from potential astronaut candidates to those that you wondered how they drove their car to work by themselves unsupervised. Some comical mistakes and some that probably took 10 years off my life.

Uber is my friend…

 

[DPApilot]

Wow, lots of variety out there in how different airlines/airframes handle this.

My takeaway from all of these various incidents is that a professional should have a really good awareness of what is normal on their aircraft, whether that’s VSpeeds, acceleration, flap setting, pitch attitudes. I like to think that if we somehow got numbers for a 33% error in weight, it would make my spidey sense tingle, but I think I need to develop a TLAR technique or similar when I’m looking at numbers.

One thing I’ve picked up from (i forget who) on here, in lieu of any actually acceleration indication in the cockpit, is 80 knots by the 1000’ markers. Not that that would have helped here as the stagnation appears to have hit about 130 knots, but if we’re doing a full length takeoff it’s always something I mentally cross check on the roll.

Or one could pull a @Boris Badenov and ask “Are we on the long runway?” while you barrel down past the halfway point.

 

[Boris Badenov]

Or one could pull a @Boris Badenov and ask “Are we on the long runway?” while you barrel down past the halfway point.

I don't remember this clearly, but I'll bet it was that time at MDW? I was looking for branches in the gear on the post-flight.

 

[Pilot Fighter]

Certainly not uncommon amongst LO aircraft, but 19k internal is quite respectable for a modern tactical aircraft. I think the F-35C is somewhere around 18k and some change. Not sure about F-22, but I imagine it has plenty. As a contrast, the legacy Hornet was around 9.5k internal, and the F-16 was IIRC 7.2? Lol

13k internal plus 4k external was too much in the S-3.

 

[///AMG]

13k internal plus 4k external was too much in the S-3.

Yeah my old DH's who flew them before transitioning to the Hornet, all told tales of being a triple cycle tanker. We had a 28k in the 2 seat 5 wet, and 29k in the single seat 5 wet. But I think you'd be pretty hard pressed to turn that into a 5.0+ duration, if you needed to hold onto gas for 3 cycles of recoveries.

 

[MikeD]

13k internal plus 4k external was too much in the S-3.

should’ve kept the KA-3 Whales, or at least the KA-6D Intruders

 

[///AMG]

should’ve kept the KA-3 Whales, or at least the KA-6D Intruders

Haha can you imagine if the A-3 were still around? I think the A-6 could probably have been modernized in a meaningful way, a la A-6F, but the Whale? That would have been an unmitigated death trap. But it was still cool for sure. But you needed, like, real aviators to fly it

 

[DPApilot]

I don't remember this clearly, but I'll bet it was that time at MDW? I was looking for branches in the gear on the post-flight.

TEB. We were in fact on the long runway.

 

[Boris Badenov]

TEB. We were in fact on the long runway.

I knew that, I was just testing you.

 

[schloopy]

Not sure if you are seeing a different source, but what you posted doesn't mention a power reduction, but rather a speed reduction. Two very different things.

You are correct, I had seen a separate discussion more specifically identifying power loss, but the linked article does not say that, that’s my mistake. I’d say my general point still stands but I apologize for the confusion.