Air Canada 767 Problems at Madrid

[Mr Mac]

Well done AC but I would bet that was a long 4hrs for SLF and crew up there.
kind regards

Mr Mac

[tdracer]

Originally Posted by Auxtank

Now, why did they do that? Genuinely interested to know.

Surely it wouldn't be a weight consideration. Was it part of certification - keeping it simpler, etc.

When the 767 was originally certified, it was considered a mid range (certainly not intercontinental - this was before ETOPS was envisioned) and there was little difference between the MTOW and the MLW, so it was decided that there was no need for fuel dump capability.
However, the MTOW gradually crept up (eventually over 400k lbs.), while the MLW stayed the same (320k if memory serves, but don't quote me on that). At some point in there the Feds said enough is enough and insisted fuel dump be added. Memory says it was basic on later builds but again don't hold me to that.
I don't know anything about it being removed...

[Spooky 2]

I flew a former Qantas 767-200ER and it did not have a jettison system installed. Later high gross weight aircraft such as the CAL/UAL 767-224ER all had the fuel jettison installed.

[Seat4A]

He was onboard AC837 and posted some videos and still photos. Great "front row" seat.

https://twitter.com/thelastfedor

[Catwalk Dweller]

Here's how SkyNews covered this "Breaking News" at 1616Z today (3 Feb): A screenshot from flightradar24.com was shown, showing the same holding pattern posted by Airbubba previously. Then came this voiceover:

The aircraft is holding over the airport, but before landing "first it must get rid of all fuel on board."

Well, it certainly will land after that, alright!

Anyway, made me laugh . . .

[Airbubba]

Originally Posted by 568

Didn't know if the gear was down, I assume it wasn't retracted after rotation, so my assumption is that the gear limit speed is 270 knots or m 0.82.

Yep, the claim that a B-763 is holding at 340 knots with the gear down is nonsense in my opinion.

Originally Posted by NWA SLF

Believe dump was eliminated when they added winglets but don't quote me on that one.

More nonsense, many 767's with winglets have fuel dump operational.

Originally Posted by gearlever

A300 no fuel dump

Wrong again, fuel dump is an option on both the B4 and the A300-600.

[568]

Originally Posted by Airbubba

Yep, the claim that a B-763 is holding at 340 knots with the gear down is nonsense in my opinion.



More nonsense, many 767's with winglets have fuel dump operational.



Wrong again, fuel dump is an option on both the B4 and the A300-600.

As always, on point Airbubba.

[DaveReidUK]

Originally Posted by Airbubba

Yep, the claim that a B-763 is holding at 340 knots with the gear down is nonsense in my opinion.

Quite so.

Averaging the GS around the hold would suggest a TAS of around 280-285 kts, after adjusting for wind, which at 7500' would equate to about 250 KIAS. So no surprises there.

I suspect the OP's 340 kts was a typo for 304 kts GS on the downwind leg of the hold.

[zerograv]

Originally Posted by tdracer

while the MLW stayed the same (320k if memory serves, but don't quote me on that).

Your memory serves you correctly !!!

145 tons is about 320k lbs.

Some older airframes do NOT have Jettison installed, and a glance at the remaining Air Canada 767 fleet seems to fit the profile of being older airframes.

[longisland]

I flew for a US carrier that had about 20 767-200s. They did not have a fuel dump system. 320,000 lb max tkof.

The 767-300s we got later had a fuel dump system from the center tank(s) only, as I recall. I think 407,000 max tkof weight.

[gearlever]

Originally Posted by Airbubba

Wrong again, fuel dump is an option on both the B4 and the A300-600.

Yep, my bad.
Thx

[787PIC]

Safe Landing in Madrid

https://www.cbc.ca/player/play/1692914243975
Kudos to Air Canada crew!
They handled this emergency perfectly.

[Dropp the Pilot]

Ya think? I'll disagree. Landing after 35 minutes might get you a "perfect", but after 4 hours of shilly shally not so much. Engine failure on a two engine airplane? Land. There are no reasons for delay. Here endeth the lesson.

[admiral ackbar]

From Flyertalk

[Airbubba]

Originally Posted by Dropp the Pilot

YEngine failure on a two engine airplane? Land. There are no reasons for delay. Here endeth the lesson.

Well, one could argue that Air Canada has previously demoed more 767 glider time than all other carriers combined.

[Dave Therhino]

Originally Posted by Auxtank

Now, why did they do that? Genuinely interested to know.

Surely it wouldn't be a weight consideration. Was it part of certification - keeping it simpler, etc.

I wrote the material below in a thread some time back to explain the regulation that contains the requirements that determine whether a jettison system must be installed. Hopefully this responds to your question. The earliest 767s with the dry center wing box were not required to have a jettison system. Whether subsequent variants were required to have jettison depended on their thrust rating and their max takeoff weight because, as discussed below, it's a quick return to land climb gradient requirement that determines if jettison is required. Whether jettison was actually installed on those variants could have been driven by it being required or by the customer electing it as an option. Here's my previous post:


The regulation that determines whether a jettison system is required is 14 CFR 25.1001(a). It has nothing to do with the relationship between max takeoff weight and max landing weight. The requirement for a jettison system is instead based on climb capability at a weight equal to max takeoff weight minus the weight of fuel necessary for a 15 minute flight consisting of a takeoff and return to land. If the climb gradient requirements of sections 25.119 (all engine climb in the landing configuration flaps down gear down) and 25.121(d) (engine out climb in the approach configuration flaps down gear up) cannot be met at this weight, then a jettison system is required by 25.1001(a).

The flow performance of the jettison system, if required by 25.1001(a), is required by 25.1001(b) to be able to get the airplane within 15 minutes to a weight that allows the airplane to meet the climb gradient requirements of 25.119 and 25.121(d).

The braking system regulation, section 25.735, sets the energy absorption capability requirements for the brakes. Landing at max landing weight at anticipated speeds must be withstood repeatedly as normal operation with no damage other than normal wear. Landing at max takeoff weight must be withstood without hazard, but parts can be destroyed or require inspection/maintenance. The structural regulations (25.473) set the landing loads that must be met by setting descent rates that must be accommodated as limit loads at max takeoff weight (6 feet per second descent rate at touchdown) and at max landing weight (10 feet per second descent rate at touchdown). A design can be limited by the braking and structural regulations to a maximum landing weight that is significantly less than the maximum takeoff weight, and whether or not a jettison system is required would have nothing to do with this. It's all design choice - how strong do you want to build your gear and brakes, and what climb performance do you want to provide.

Of course, performance information (climb gradient and runway distance) for landings in excess of the maximum landing weight up to the max takeoff weight is required to be provided in the AFM by 25.1587(b)(3).

So yes, as most of you pilots already know, you can theoretically land safely above the maximum landing weight, but you are going to at least have some inspections required afterward, and worst case could blow the tires and damage the brakes and wheels. I am not qualified to speak about the judgment of whether you should do this in a real world situation.

[tdracer]

Originally Posted by Dropp the Pilot

Ya think? I'll disagree. Landing after 35 minutes might get you a "perfect", but after 4 hours of shilly shally not so much. Engine failure on a two engine airplane? Land. There are no reasons for delay. Here endeth the lesson.

I'm thinking they might have been reluctant to perform an overweight landing when they knew they already had a damaged undercarriage...

Anyone know if the engine was shutdown, or just run at lower power/idle? That's some pretty nasty fan blade damage.

[PJ2]

From the twitter feed linked to earlier in the thread, the engine appears to be running, (occasional compressor stalls accompanied by flames out the back, plus sound). The thrust level appears to be higher than idle, but we'll know when the data is read.

[lomapaseo]

Originally Posted by tdracer

I'm thinking they might have been reluctant to perform an overweight landing when they knew they already had a damaged undercarriage...

Anyone know if the engine was shutdown, or just run at lower power/idle? That's some pretty nasty fan blade damage.

Well the hp might be able to run at idle and drive some externals,but the lp is sure gonna screw up the flow into the HP seeing as the LP Turbine won't feel much load from the wide open fan blade tips. Any successful attempt to run at power is gonna cook the HP turbine as it tries to salvage the engine cycle. Hopefully in a worst case you can baby the engine until a worse case emergency

[fdr]

Originally Posted by Dave Therhino

The regulation that determines whether a jettison system is required is 14 CFR 25.1001(a). It has nothing to do with the relationship between max takeoff weight and max landing weight. The requirement for a jettison system is instead based on climb capability at a weight equal to max takeoff weight minus the weight of fuel necessary for a 15 minute flight consisting of a takeoff and return to land. If the climb gradient requirements of sections 25.119 (all engine climb in the landing configuration flaps down gear down) and 25.121(d) (engine out climb in the approach configuration flaps down gear up) cannot be met at this weight, then a jettison system is required by 25.1001(a).

The flow performance of the jettison system, if required by 25.1001(a), is required by 25.1001(b) to be able to get the airplane within 15 additional minutes to a weight that allows the airplane to meet the climb gradient requirements of 25.119 and 25.121(d).

The braking system regulation, section 25.735, sets the energy absorption capability requirements for the brakes. Landing at max landing weight at anticipated speeds must be withstood repeatedly as normal operation with no damage other than normal wear. Landing at max takeoff weight must be withstood without hazard, but parts can be destroyed or require inspection/maintenance. The structural regulations (25.473) set the landing loads that must be met by setting descent rates that must be accommodated as limit loads at max takeoff weight (6 feet per second descent rate at touchdown) and at max landing weight (10 feet per second descent rate at touchdown). A design can be limited by the braking and structural regulations to a maximum landing weight that is significantly less than the maximum takeoff weight, and whether or not a jettison system is required would have nothing to do with this. It's all design choice - how strong do you want to build your gear and brakes, and what climb performance do you want to provide.

Of course, performance information (climb gradient and runway distance) for landings in excess of the maximum landing weight up to the max takeoff weight is required to be provided in the AFM by 25.1587(b)(3).

DTR, quite so.

Many oddities on a takeoff will result in the sort of decision that this crew had to make, and it is definitely in the realms of decisions made under uncertainty.

The F18 off the wing is notable, assume that an airborne inspection was requested by the Captain, or accepted if offered by ATC. That may have provided the crew with the information that would otherwise be missing to them after the entertainment of a clunk-bang event on the takeoff above V1. A tyre failure can result in an engine failure, sometimes, not all that prevalent. the first failure may not be determined to be a tyre failure, the crew may only known they have an engine failure with hints of severe damage, until someone looks out a cabin window and sees excess tinsel and stuff (maybe). The potential for one engine to damage another is relatively low in a pylon mounted engine case from one wing to another. engines on the same side have been damaged by a single failure on a number of occasions. Across the aircraft a HPT/LPT letting loose has caused damage to the other engine on occasion, with a ricochet off the ramp.

So, chance that both engines are damaged is not high, it is also not zero, but it is not high. An immediate landing is possible, but is compromised in this case by the tyre failure, depends on the availability of Edwards or similar maybe, as your stopping is dependent on variables outside of certification. A single flat tyre, not a problem, but if it takes out the other 3 on landing, the things are awkward, 1/2 TRs, 1/2 braking, control authority etc... becoming a bit interesting, and a lot of unknowns, stuff that the OEM pays TPs to play with, without pax.

When would a multi engine failure be an elevated risk?

birdstrikes, with large flocks. The larger fans deal with birdstrikes better than small donks, there is a smaller relative area of intake air to the core and that is protected by larger roots of the blades, birds tend to be centrifuged, still happens though.

An unknown cause to pilots:

• contaminated fuel. bad fuel can result in losing any or all engines, but isn't a high prevalence, and contamination appears to affect engines more at lower power than higher power.
• Fuel icing. BA038 sort of deal. Happens later in flight after cooling of a system, and needed the power to be low first up to cause buildup.
• Airframe icing: SAS MD80 style. not much of a choice left to make. failure is going to be prompt and more or less symmetric for an aft engined aircraft with undetected ice on the wings that sheds into the intakes.

Once the crew know the failure is a tyre, then the urgency to land overweight is reduced. Even on a small jet, such as a Gee whizz, or a Lear, a tyre/wheel/brake disk failure may well cause damage to the flaps, and possibly to the same side engine, but is not likely to cause bilateral damage, unless... a disk happens to spit its dummy at the same time, which is unlikely. A fan blade or two going cross country is possible, but the disk has the energy to hurt and is not likely to part ways. It it does, your decisions are going to come up rather quickly and be made for the pilot.

The OEM on the topic had a single comment of note, that the Autoland function is not certified for the overweight landing. The logic that they operate under would not change due to being a bit heavier, it is a relatively simple geometric progression, and that doesn't care about the start conditions so much. However the suggestion was to manually land. aiming for lower than 360FPM around the touchdown which would rattle teeth anyway. (ground effect is dependent on CL, so a reduced flap setting is going to result in a lower ground effect in the flare, so the flare needs to ensure a reducing in sink rate from pitch change in the flare process. As we always do.... or try to anyway)