I am curious about the tyres and brakes.
On a car, after standing for a few months the tyres are flat spotted, and gives a bumpy ride for a few days.
The brake fluid tends to gain moisture and then corrode the pistons in the brake callipers in a car. How soon is this an issue for an aeroplane?
What happened to the manual trim wheel issue?
Do the Europeans still want a second electric trim motor?
There is unfortunately a new factor in play. A lot of companies who have been having their employees work from home via skype etc. plus vpn The bosses are now thinking, why do we need these big office buildings The next thing they are going to think is: why do we need to air travel to all these meet...Jump to post
with immediate effect travel from USA, UK, ITALY, IRAN CHINA ETC into south Africa is forbidden. see speech by sa president Ramaphosa this evening. Schools are closed from next Wednesday until after Easter. Total infections detected so far in south Africa is 51. It was only 7 a week ago.The first 7 ...Jump to post
MCAS does not start up only when high AOA is reached, it is continuously active in the background, checking the AOA multiple times per second. (this might be where the bit flip requirement comes from) Disabling electric trim did not switch off MCAS 1.0. What is not clear is if MCAS acts on the eleva...Jump to post
The winter rainfall at cape town is mostly coming from the west. the winds are north west so runway 01 would be in use. if the weather system has been going for a few days then all the coastal airfields will have the same weather ie Overberg, PE, east London and Durban. the best alternates would be ...Jump to post
I will assume that boeing can optimize a structure to be as light as possible, ie all parts are near maximum allowable stress. This is the problem. If aero changes are now made which cause increased loading, they are overstressed and up the creek. This is why any changes which lead to additional loa...Jump to post
I remember when I thought after 3 years in my profession I knew everything..... I don't think I know everything. I think I'm perfectly capable of sitting at the adult table and reasoning through issues just as complex as they do. Do you know what another good word for experience is? Codified bias. ...Jump to post
Once the dust settles with the MAX, would the FAA 'go-back' and look at previous certifications provided for lets say, the 787-8, 787-9, 747-8i, etc? i.e basically going on full CYA mode..... The minimum action on all current types (including 737NG) per NTSB recommendations, if not already complete...Jump to post
The main problem with using carbon as wing structure is although it is much stronger than steel, the modulus of elasticity (or the amount of deformation per load) is the same or slightly better than steel. This results in a wing, for the same strength as the steel one, deflecting much more. As long ...Jump to post
JNB TO CPT is a 2hr flight.
The other destination that CPT is also used for is flights to Antarctica, mainly freight I think.
The business rescue will probably point out that the airline is heavily overstaffed. The strike a few weeks ago was in part due to a proposed 20% staff cut. If you look at the check in counters at jhb airport. Comair(british airways) will typically have 2 staff at counters. SAA will have up to 7. Th...Jump to post
I notice on flightaware that on Saturday, Boeing was still doing what looks like stall testing on a 737max. What could they be testing if everything was handed over? As for testing with MCAS switched off. Just the switches wont do it, because mcas is still running in the background. It would take a ...Jump to post
Unfortunately these days big projects are driven by project managers, who don't always appreciate engineering consequences, and mostly look at time lines. If new computer hardware takes years to certify and just re-using and old one with some updates takes a few months, then that is what they will c...Jump to post
For the Lion air case: the question is why did they stop trimming nose up? there are 2 possibilities: 1. they did not know how. 2. the electric trim drive motor failed. There are signs of intermittent trim action just before the final moments. This could open up another can of worms. What was the du...Jump to post
The Lion air pilot with the flu was pulling 105lbs on the yoke at times. That is pretty impressive for a sick guy. The answer is maybe more simple. The pilots simply got tired of pulling back on the yokes. When you have to pull that hard on the yoke, I do not think you are in a position to think of ...Jump to post
I still don't understand how a larger stabilizer would have helped with this issue. Because destabilizing surfaces in front of CG can be compensated with larger surfaces behind the CG. But how would it help maintain a constant stick force gradient when the destabilization is non-linear with increas...Jump to post
The larger stabilizer was never going to happen.
The implication is that the structural design of the rear half of the aircraft would have to be redone, due to larger stabilizer forces, and possibly the structure strengthened. That late in the process, this was not going to happen.
for mcas 1.0 working correctly, at high AOA the stick force would increase and the stabilizer would trim nose down. when AOA had reduced it was supposed to return to the previous trim setting. One of the JATR comments was whether, when trimmed nose down, there was enough elevator authority to mainta...Jump to post
The fuselage also flexes by bending downwards, as it cantilevers forwards and backwards. See the Hawaii 737 that had part of the forward roof break off in mid flight. This was found out to be high cycles on aircraft parked in salt air So a few hard landings will work the pickle forks in the fore aft...Jump to post
I believe the 120 hours per aircraft is mostly for purging all fluids, cleaning the systems and tanks and refilling. The potable water system needs to be clean and free of bugs.. Then something non-aircraft: the heating elements in the stoves could have absorbed moisture, which is going to make them...Jump to post
It would be interesting to know what the duty cycle is on the stabilizer trim motor. (where 100% duty cycle is continuous max torque on motor) normal operation near in trim would only require a fraction of full torque, but in the mcas failure mode you might need full torque for a long period when tr...Jump to post
just my 2c engineers are not poets, they write in simple English so that their fellow workers can understand them properly. so mcas means: helping the aircraft to pitch up or down. there is nothing in there about stick force. so is this a hidden active control system? as for never needing the manual...Jump to post
any flight from jhb to Frankfurt flies around Libya on the west sideJump to post
how about this idea.
the max needs extra training, but its the same as the ng
therefore ALL 737 pilots need extra training....
I am sure Boeing does not want to go there.
maybe the FAA is thinking about this, and is trying to find the best middle ground.
if its different, then re-certify.
Ok so possibly the aero wind tunnel model testing and the computer cfd modelling showed up an anomaly and they hoped for the best. From the above effects of MCAS one item that is being ignored is: it leads to increasing control forces ,i.e. it trims nose down and forces the elevator down as well and...Jump to post
Can anyone confirm when MCAS was implemented. I got the idea the light control forces were noticed during flight testing. This is a bit late in the day. It leaves only one option. A software fix. Any structural or aero fix would have taken years to do. As for the higher mounted engine causing more p...Jump to post
Control forces in the max are not directly related to aerodynamic forces. There is a FEEL system that provides stick forces decided on by the flight computer. The magnitude of the forces are affected by the systems such as mach trim , speed trim and possibly mcas. when MCAS needs to activate, the no...Jump to post
Johannesburg has 4 gates for A380 (I think) with double boarding ways. This can be used on any aircraft, like the LH 747-8 and speeds up boarding, so will definitely be a benefit to any airport. On domestic flights at JNB they use the one jet-way for the front and the back half pacs walk down the st...Jump to post
Can someone confirm the following: MCAS only operates approaching stall. therefore for the rest of the flight envelope it does nothing. Should it not be called 'Approaching stall help system' Then if it does nothing for the rest of the flight envelope, how can it make the plane feel the same as a NG...Jump to post
Note the sentence below: The FAA is reassessing the extent of force required to manually counteract nose-down commands in extreme circumstances, by turning a wheel—known as the trim wheel—located between the pilots. This is the hidden "approaching train smash" The utube video from the Amer...Jump to post
agree with above. I was taught to fly where trim is used to enable the plane to fly hands off, not to reduce forces. The 737 has software protection to prevent overstress of the elevators, which shows itself has higher control forces. The parts of the flight envelope where this happens should be poi...Jump to post
The 737 has hydraulically powered elevators. Why should the stick force become higher at high speeds? I searched and found an article on: Elevator Feel and Centring system. my take on this: its a system that increases the required force on the control stick at high speeds ( is this to limit any exce...Jump to post
The MCAS software update does not make sense. The logic of disabling MCAS if the two sensors disagree by more than 5 deg, assumes that the faulty sensor is the high value. What if the low value is the faulty one. You are then approaching the edge of your flight envelope with no protection.(According...Jump to post
my take on this: MCAS was put in to prevent a certain AOA value being exceeded, due to more powerful engines. (does anyone know this value, and what can the NG do?) When there is an AOA disagree MCAS is deactivated. Now there is no safe way to fly this aircraft as the pilots have no idea as to what ...Jump to post
being an eyewitness is an acquired or learned skill. as a structural engineer with a degree and close to 40 years experience, when I visit a building site, I can very quickly see most big errors. this is due to the fact that I have a frame of reference. i.e. I know what to expect and any missing or ...Jump to post
Is it possible to load a 737 max to aft of aft cg limits? It should not be possible. I was on a 737 800 with a delay due to luggage being offloaded and the LCG being recalculated. is this correct? If you are loaded tail heavy, the aircraft could fly ok with flaps out when the Longitudinal centre of ...Jump to post
the reason most aircraft are painted white is to keep the temperature down. A black aircraft will see a skin temperature of more than 100 deg c where as the white one will probably be above 30 deg c. having a black aircraft is burning money, in extra fuel burned for aircon. (these temps are obviousl...Jump to post
just a question?
I assume there are vents in the passenger cabin floor so that cabin pressure can equalize with the cargo hold to prevent a floor collapse when a cargo door opens in flight.
Does the cabin air con pressurize the cabin and then bleed through to the cargo hold?
Most dangerous for me is when the plane is about 20m or so from the gate and the pilot stops for a moment, and some idiots get up and reach for their bags in the overhead bins, and then the plane move again. These bozos then grab at anyone and anything to prevent taking a fall. This can lead to seri...Jump to post
In my company in South Africa, they can ask for a doctor's examination if they notice a pattern of excessive use of sick leave. The doctor then will only say, you are fit for work or unfit. The details remain confidential. I would think that its the same in Europe. It would take quite a number of si...Jump to post