Unexpected Rotation

[pelmet]

I have read of this kind of thing happening before. Perhaps in this case, they were going quite fast and deemed an RTO as too risky but if it happens at any significant speed below V1, I would suggest an RTO. It would be interesting to know how the aircraft handled in the air both immediately after liftoff and for the rest of the flight and if anything could have been done like moving weight more forward in the cabin for the landing.


C-GEKX, an Air Canada Boeing 737 MAX 8 was operating as ACA234 from Vancouver Int'l
(CYVR), BC to Edmonton Int'l (CYEG), AB with 2 flight crew, 4 cabin crew, and 160 passengers on
board. During the take-off role, the nose of the aircraft rose unexpectedly. The flight crew was able
to hold it down and continued the take-off. The flight continued and landed safely in CYEG.
After landing, it was discovered that 89 bags which were shown on the Load Data Final document
as being in the forward hold, had actually been loaded in the aft hold. The company is conducting
an investigation.

[fish4life]

I have read of this kind of thing happening before. Perhaps in this case, they were going quite fast and deemed an RTO as too risky but if it happens at any significant speed below V1, I would suggest an RTO. It would be interesting to know how the aircraft handled in the air both immediately after liftoff and for the rest of the flight and if anything could have been done like moving weight more forward in the cabin for the landing.


C-GEKX, an Air Canada Boeing 737 MAX 8 was operating as ACA234 from Vancouver Int'l
(CYVR), BC to Edmonton Int'l (CYEG), AB with 2 flight crew, 4 cabin crew, and 160 passengers on
board. During the take-off role, the nose of the aircraft rose unexpectedly. The flight crew was able
to hold it down and continued the take-off. The flight continued and landed safely in CYEG.
After landing, it was discovered that 89 bags which were shown on the Load Data Final document
as being in the forward hold, had actually been loaded in the aft hold. The company is conducting
an investigation.

I’d be curious what the effect on braking action and distance would be like if you tried a reject in a scenario like that once the nose was already off

[pdw]

The downlift of the tailplane got help to raise the nose from the further aft envelope (misplaced baggage). Way less downforce then needed to pop up nose to rotate….at the much slower airspeed. Surprise ….the nose lifted off early at a normal take-off elevator trim setting. Some camera pick that up ?

Must be still early in the roll; so to have runway / braking stoppage at that point depends on (the usual) reverse thrust engaged asap, weight and ground speed.

[pdw]

It would be interesting to know how the aircraft handled in the air both immediately after liftoff and for the rest of the flight and if anything could have been done like moving weight more forward in the cabin for the landing.

The passenger seating is near maximum (maybe a few available up front?), yet fuel payload could be matched for an hour of flight (Edmonton) so takeoff thrust and lightened nose wheel can press lower levels slightly “aft “ too. It’s understood it’s not much at each level, but tank movements are also least when filled to max. The report says “89 bags” ….times 50lbs or less, so could be 3000-4000lbs in the “more-aft” compartment. If they were supposed be placed ahead of the wing instead, that’s quite a difference … if requiring an elevator deflection for uplift on the tail plane to get the nose back down.

A hard forward yoke input (elevator FORCED down) will get into a positive g-force exerted on the HS where it’s otherwise negative. If the tail plane wings are designed to accommodate that much opposite g that in this case was used to press nose-down (I.e. as is envisioned could happen in extreme turbulence) then structurally nothing is exceeded.

[pelmet]

Another interesting one.....

"Argentinean investigators have found that a Flybondi Boeing 737-800 was out of balance before it tipped up and struck its tail while attempting to depart from Iguazu Falls airport last year.

Argentinean investigators have found that a Flybondi Boeing 737-800 was out of balance before it tipped up and struck its tail while attempting to depart from Iguazu Falls airport last year.

The aircraft had just commenced its take-off roll from runway 31 when, about 6s after its thrust levers were advanced, it abruptly pitched up at about 30kt, causing its aft fuselage to scrape the ground. Its crew aborted the departure and returned to the parking stand.

Argentinean investigation authority JIAAC says the aircraft was transporting 65 passengers and a crew of six on a service to El Palomar at night on 16 July 2018.

Budget airline Flybondi had acquired the aircraft (LV-HQY) three months earlier, in April, after it came off lease with Turkish Airlines as TC-JGH.

It had been configured with 165 economy seats for the Turkish carrier but it was refitted in France with 189 economy seats for Flybondi.

Airport handling documentation was updated, as required, to reflect the aircraft’ new weight-and-balance envelope under the new seating layout, says JIAAC.

The load and trim sheet for the flight lists the passengers as being distributed primarily in the front of the aircraft, with 38 in the two forward cabin sections and 27 in the two aft sections. This put the calculated centre-of-gravity at 22.2% of the mean aerodynamic chord.

But JIAAC says the actual distribution “did not correspond” to that prepared on the sheet. All but a few passengers were located in the two aft sections, with just one person in the front cabin where 20 were supposed to be sat.

The inquiry says this distribution would have shifted the centre-of-gravity to a position 38% of the mean chord, placing it “outside the flight envelope”.

Although the cockpit-voice recorder did not provide relevant information about the accident, analysis of the flight-data recorder enabled Boeing to estimate a centre-of-gravity figure close to 40%, consistent with the calculation.

The twinjet received damage to the aft fuselage underside and tail-skid but none of the occupants was injured.

JIAAC has yet to reach conclusions on the circumstances of the accident but the carrier has revised procedures for controlling distribution of passengers and cargo on its aircraft.

The inquiry turned up a number of discrepancies in the aircraft preparation system. At the time of the event, Flybondi was using a company called FlySeg for dispatch at Iguazu Falls. The company operated from a structure similar to a shipping container located outside, about 200m from the check-in area, with a poor internet connection.

Although check-in is performed with a Radixx computer system, the company uses a separate and independent system called ARMS for 737-800 aircraft dispatch.

The airline’s dispatch manual states that the ARMS system will be used to calculate flightplans and dispatch, but also has a procedure to carry out dispatch manually, indicating the forms necessary for determination of centre-of-gravity position.

JIAAC says the weight-and-balance envelopes in the ARMS system and those shown for manual dispatch – in the airport handling documentation – were different, with ARMS containing the correct version. The dispatch manual also lists methods of calculations for moments acting on an aircraft, using a Boeing 737-200 as a reference aircraft."

[boeingboy]

Whats really concerning is they did it again a few days later...this time nose heavy!

An Air Canada Boeing 737-8 MAX, registration C-FTJV performing flight AC-557 from Los Angeles,CA (USA) to Vancouver,BC (Canada) with 103 people on board, was departing from Los Angeles' runway 25R when the crew noticed during rotation for takeoff that the aircraft was slightly nose heavy. The aircraft climbed out, the crew subsequently verified the load sheet and found out, that all cargo had been loaded into the forward cargo hold, which showed the actual CG 5.8% (in relation to MAC) forward of the computed takeoff CG. The crew continued the flight to Vancouver without further incident.

http://avherald.com/h?article=4f2c0bab&opt=0

[pdw]

The first (opening post) does a wheelie just before rotation, and keeps going into flight
The second example (Argentina) does the wheelie at the beginning of the roll, and thereby exposed beyond flyable. Those show the positioning of the mains just aft of CofG enable a tip warning of these aft loadings, the second being more serious is warned off by the earlier tip-up after 6 sec / 30kts down the runway.

This noseheavy rotation though isnt’t going to be subject to the same telling tipup-like warning in advance, and in this case it continues into flight after the nose-heaviness is noticed only there at rotation time. If it is an un-flyable nose heavy like the second wheelie example above, might be a harder error to spot unless that scenario is being tipped off in advance by tire sensing (flatter nose tires or depressed nose strut or even the heavier turning resistance onto the active ).

[PilotDAR]

Airplanes do not do "wheelies".

Airplanes may "tip", though this does not happen while under pilot control.

The positioning of tricycle main landing gear behind the C of G is not done to provide a warning for loading by "tipping". Yes, a misloaded plane may tip backwards due to careless loading, but that is coincidental to the intended location of the MLG to result in a plane which is stable on the ground, and can be rotated as intended during takeoff with a correct C of G.

[co-joe]

Saw a Southwest 700 with a tail stand the other day, obviously tipping is a concern for them. Didn't even know that was an option.

Back to OP, the fact that AC rampies can accidentally screw up that badly and put 1.5 Tonnes in the wrong box on the load sheet or whatever system they have is scary as hell to me. That's not a small woops. And it's happened twice?

[goldeneagle]

Back to OP, the fact that AC rampies can accidentally screw up that badly and put 1.5 Tonnes in the wrong box on the load sheet or whatever system they have is scary as hell to me. That's not a small woops. And it's happened twice?

Not so sure it happened twice. In the first case, they couldn't figure out the problem till after landing, so paperwork was indeed wrong. In the second case, they apparently figured it out shortly after takeoff by checking paperworks. so where was the mistake in that case ?

[co-joe]

Back to OP, the fact that AC rampies can accidentally screw up that badly and put 1.5 Tonnes in the wrong box on the load sheet or whatever system they have is scary as hell to me. That's not a small woops. And it's happened twice?

Not so sure it happened twice. In the first case, they couldn't figure out the problem till after landing, so paperwork was indeed wrong. In the second case, they apparently figured it out shortly after takeoff by checking paperworks. so where was the mistake in that case ?

It could easily have been a paperwork error. I think AC gets their "load sheet" and trim setting via acars, we still get ours on paper. I've never heard of having 89 bags in Pit3, we only use Pit 4 for pax bags, and the odd thing like gate checks and strollers go in pit 2. For us if the load sheet showed 1.5 metric tonnes of bags in the forward pits it would set of huge alarm bells. We also do our own weight and balance calculation on an app and then both pilots compare, so the chance of 1 person putting an error that causes setting the wrong trim is much less.

One thing's for sure, it's a good thing it wasn't 189 bags or the result could have been a tail strike if an un-commanded rotation occurred.

[goldeneagle]

It could easily have been a paperwork error. I think AC gets their "load sheet" and trim setting via acars, we still get ours on paper. I've never heard of having 89 bags in Pit3, we only use Pit 4 for pax bags, and the odd thing like gate checks and strollers go in pit 2. For us if the load sheet showed 1.5 metric tonnes of bags in the forward pits it would set of huge alarm bells. We also do our own weight and balance calculation on an app and then both pilots compare, so the chance of 1 person putting an error that causes setting the wrong trim is much less.

One thing's for sure, it's a good thing it wasn't 189 bags or the result could have been a tail strike if an un-commanded rotation occurred.

One part of this that absolutely befuddles me. It would be trivial to have sensors on each landing gear leg that indicate how much weight is on that leg. Half a dozen strain guages would do the job, a dozen if you want a fancy setup that is temperature compensated with redundancy. At that point, w&b would become an exercise of confirming what the displays tell you, and if there is a disagreement between the load sheet and the readings, figure it out. I know this would be a big issue for older airplanes, but these reports are about new airplanes that rolled off the line in the relatively recent past.

[pelmet]

It could easily have been a paperwork error. I think AC gets their "load sheet" and trim setting via acars, we still get ours on paper. I've never heard of having 89 bags in Pit3, we only use Pit 4 for pax bags, and the odd thing like gate checks and strollers go in pit 2. For us if the load sheet showed 1.5 metric tonnes of bags in the forward pits it would set of huge alarm bells. We also do our own weight and balance calculation on an app and then both pilots compare, so the chance of 1 person putting an error that causes setting the wrong trim is much less.

One thing's for sure, it's a good thing it wasn't 189 bags or the result could have been a tail strike if an un-commanded rotation occurred.

One part of this that absolutely befuddles me. It would be trivial to have sensors on each landing gear leg that indicate how much weight is on that leg. Half a dozen strain guages would do the job, a dozen if you want a fancy setup that is temperature compensated with redundancy. At that point, w&b would become an exercise of confirming what the displays tell you, and if there is a disagreement between the load sheet and the readings, figure it out. I know this would be a big issue for older airplanes, but these reports are about new airplanes that rolled off the line in the relatively recent past.

Boeing put them on 747 and 777 freighters……..but perhaps they are more vulnerable to extreme situations.

Off the top of my head, the only jet airliner crash due to misloading(CG limits exceeded at initiation of takeoff) was that Fine Air DC-8 freighter in Miami.

https://boeing.mediaroom.com/2007-03-27 ... -Freighter