Qantas Airbus Engine Oil

[757guy]

There is some additional information from Aviation Week regarding some of the system failures.

Here is the link: http://www.aviationweek.com/aw/generic/s...eyond%20Engines

I have flown the A320 and A330 for Northwest Airlines (Now Delta) and suspect that reports about fuel imbalance were somewhat inaccurate. With the total fuel load on that airplane, even with one engine shut down, there would not be any significant fuel imbalance due to fuel burn on the other 3 engines considering the total flying time after the uncontaminated engine failure.

The A380 Aircraft Hydraulic system is very similar to the A320 and A330 in that there are two systems, yellow and green, with a blue system as backup. Even though the green system normally powers the landing gear functions, the yellow system can also serve the same function through a PTU, or power transfer unit. The blue hydraulic system works through a RAT or Ram Air Turbine and is not dependent on engine or electrical power to supply hydraulic power to the flight controls and landing gear. Braking can be accomplished using the hydraulic accumulators as a backup system to normal and alternate braking.

Overweight landings are not desireable, however performance planning does take into account max gross weight landings without the use of spoilers or reverse thrust.

My biggest concern as a pilot was the loss of the fuel control lever function making it difficult to shut down the #1 engine due to a fire warning. In addtion, there was no capability to discharge any fire extinguishing agent into the affected engine.

I can do without reverse thrust and ground spoilers, but braking is a desired item (which was accomplished through the alternate system). Also desired is a way to close off a fuel supply to an engine that is on fire, plus the ability to discharge fire suppression agents to put out the fire.

Good job by the entire crew. That is exactly why we have more than one pilot in the cockpit. When things start going bad, you need someone to FLY THE AIRPLANE, and another to work the problem. Every once in awhile someone suggests that we don't really need 2 pilots in a commercial flight operation. This event reinforces why we do.

757 Guy

 

[FowVay]

Was that thing leaking fuel from the left wing? I don't recall whether a bladder was punctured or not.

 

[Shannow]

According to the evening news, a tank was punctured.

 

[FowVay]

That's what I thought. It was for this reason that the pilots couldn't control the outflow of fuel from that side of the aircraft. It wasn't because of the fuel being consumed by the engines but rather by the fuel leaking out of the bladder.

I wasn't aware of this until I started reading but this particular airplane only uses thrust reversers on the two inboard engines. That means that with the #2 engine out of commission it had only the #3 engine on the other wing to help slow it down. It seems that the plane was designed to have more than adequate brakes and the thrust reversers are just sort of a luxury. 757guy would have to address the aspect of stopping a wide-body with and without thrust reversers. There is a super cool video on youtube about the initial testing of the A380 and the brake test.

And JetStar, you are absolutely correct about the FADEC and that 777. I was thinking about the initial write-up about the pilot requesting thrust and the plane not responding. At first it was only on the one engine but ultimately both engines went to fast idle and left them hanging. It was later determined to be icing that caused the fuel flow problem. Thanks.

 

[dkryan]

This is from my daily e-mail aviation news from www.aero-news.net as of Saturday, November 13th.:

Rolls-Royce: A380 Problem Limited To Trent 900 Engine

Component Which Cause Oil Fire Identified

Rolls-Royce says it has identified the Trent 900 engine component which it believes caused the failure of an engine on the Airbus A380 operating as Qantas flight QF32 on 4 November 2010.

In a statement released to the media, Rolls-Royce says that immediately following the incident, a series of engine checks was introduced on the Trent 900s to understand the cause and to ensure safe operation. They were conducted in parallel with a "rigorous examination" of all available evidence, including data from the damaged engine and its monitoring system, analysis of recovered material and interrogation of the fleet history.

The investigations have led the company to draw two key conclusions. First, as previously announced, the issue is specific to the Trent 900. Secondly, the failure was confined to a specific component in the turbine area of the engine. This caused an oil fire, which led to the release of the intermediate pressure turbine disc.

The company said its process of inspection will continue and will be supplemented by the replacement of the relevant module according to an agreed program. "These measures, undertaken in collaboration with Airbus, our Trent 900 customers and the regulators have regrettably led to some reduction in aircraft availability. This program will enable our customers progressively to bring the whole fleet back into service," the statement says.

Trent 900 Engine

"Safety is the highest priority of Rolls-Royce," said Rolls-Royce CEO Sir John Rose. "This has been demonstrated by the rapid and prudent action we have taken following the Trent 900 incident. We have instigated a programme of measures in collaboration with Airbus, our Trent 900 customers and the regulators. This will enable our customers progressively to bring the whole fleet back into service. We regret the disruption we have caused."

Rolls-Royce said it is cooperating fully with the government authorities investigating the incident.

 

[FowVay]

That sounds expensive. Rolls must be trying to catch up to Toyota on the recall list. :O)

Good info!! Thanks.

 

[757guy]

FowVay,

You asked about the effect of reverse thrust on a widebody airplane. For the benefit of other members, the name "reverse thrust" is somewhat misleading because the engines never reverse, but rather the fan stage airflow is diverted sideways out of the engine to create an air dam creating resistance to forward movement. Next time you fly, notice the engine cowling area when reverse thrust is applied. You will notice diverter doors and guide vanes that block the rear of the engine when reverse thrust is applied.

What provides most of the stopping power on new commercial aircraft is the use of autobraking. Autobrakes work through the anti-skid system so that when the aircraft senses that the aircraft is on the ground (through tilt switches in the landing gear and inertial navigation ground speed vs. wheel rotation speed), the aircraft will automatically apply braking at a preselected rate. The Autobraking will kick off when brakes pedals are applied or if the auto ground spoilers are stowed.

On a Boeing 757, I can select autobraking 1 through 5 depending on what level of braking I want to use. Most often, I will select autobrakes 1 unless the runway I am landing on is short or has some sort of contaminants, i.e., snow, wet, etc. What the Autobrake system will do is slow the aircraft at a predetermined level of deceleration in ft. per second. Whether or not I use reverse thrust, the autobraking system will give me the same deceleration rate. With heavy reverse thrust, the braking system just doesn't have to work as hard. Autobraking is better than normal braking because it is applied consistantly and evenly throughout the landing rollout.

When landing a widebody, reverse thrust provides some of stopping power, but the braking system does most of the work. Landing performance penalites for an inoperative brake are the most restrictive. Not having a thrust reverser results is a less restrictive landing weight penalty. The flight planning system and runway landing performance calculations are almost always done without reverse thrust being available. (It is almost always used, but planning a landing without reverse thrust is more conservative and allows for a greater margin of safety.)

Hope that information helps,

757 Guy

 

[757guy]

Here is a newspaper link on this incident: http://www.heraldsun.com.au/ipad-applica...6-1225952350842

 

[nthach]

There are several jet engine oils in the market, I remember seeing a few cases of BP Turbine Oil 2380 on a fuel cart at either SFO or OAK a few years ago. Mobil and Shell also make jet engine oils as well.

 

[FowVay]

I guess the oil type was the original question on this thread. According to Rolls Royce Service Bulletin 12-F139, all Trent series engines specify the use of a High Thermal Stability (HTS) oil. Examples of such oils are BP2197 and Mobil Jet Oil (MJO) 254.

These two products are what is placarded on the Trent engines I'm familiar with. No special requirement is noted in the service bulletin relating to the alternating of these two fluids. Mixing is not recommended but flushing is not required if alternating between the two.

 

[Tom NJ]

Per another airline forum, the oil in these Qantas engines was Air BP 2197, which is what I expected since it is the best Trent approved oil available (the fact that I have a patent on its POE base oil does not make me biased)

Both BP 2197 and MJ 254 use a special super anti-oxidant that is known to degrade certain seals under severe conditions, although seals do not appear to be implicated in this oil fire failure. Shell has a new HTS oil called Ascender which uses a different anti-oxidant system, but it is still going through approvals.

Tom NJ

 

[Shannow]

Tom, when it's your own child, it's not bias.

News tonight 14(?) engines to be replaced before they get back in the air.

And picture's of a cut wing strut, and a talk around load distribution, load redistribution, and safety factors