khaosai

how much for a helicopter flight from bangkok to hua hin ? hate the 3 hours in the car

That would be pretty expensive I think. I flew on a light aircraft quite a few years back from Hua Hin to Bangkok. It worked well but was probably not much quicker than driving when you add in the airport hassles. I think the company was called SGA.

Hi,

The effect of more baggage being loaded onto a large aircraft will vary. If 400 passengers each carry 10kg more baggage then the fuel burn increase may be approx 300kg on a short flight and approx 3000kg on a longer range flight. Cost and payload will become a factor.

A deceased person will be repatriated on passenger aircraft. On large commercial aircraft the holds are all pressurised. Some holds also allow temperature control.

Some airlines will carry a mortality kit onboard to cover a death that occurred in the cabin when in flight. The body will then be placed somewhere appropriate. That may be the galley, emergency exit during cruise or a passenger seat. All of this will be done with as much dignity as possible.

That would take a bit of doing for a trained crew member to allow the aircraft to descend 5000ft and not be aware of it.

Hi,

On all fixed wing light aircraft I have flown the primary flight instruments were set up in front of the pilot who sat on the left hand side.

When you try to fly any aircraft from the other seat for the first time it's a challenge both from a tactile and visual perspective.

Seniority, qualification and experience on a four crew trip does not necessarily determine who will be the pilot in command.

When it comes to the aircraft doing an auto land it will have lower allowable wind limits than when flying manually. The automation generally does a great job of approach, touch down and subsequent roll out.

Hi,

It's always difficult to get the complete picture of what actually happened, but at the end of the day the crew made a decision to divert. Safety was of primary concern to them.

Damage to a flight deck window may not necessarily mean and immediate descent and diversion. It may be possible, depending on the problem encountered to continue the flight to destination. This decision of course may vary on the aircraft type involved.

Things that can go wrong are electrical arcing due to the windshield being heated, cracking, delamination and shattering.

Arcing, shattering or cracking may well allow the flight to continue. The checklist will offer guidance on this as part of the decision making for the crew.

If the window deforms or an air leak occurs then you would land at the nearest suitable airport and descend to a safe altitude above ground or ten thousand feet whichever is higher. Again this would be highlighted in the checklist.

What's important is a correct assessment of the situation. If unsure then the best logic to apply is the safest course of action.

I'm a bad flyer and would consider malaysian airways - just bad luck imo, Thai Airways are more risky by far, they have been V lucky recently not to have a major accident and wd steer well clear if I were on anything other than the A380

It's a great aircraft to travel on as a passenger but I am curious to why you would steer well clear of TG unless on the A380 ?

While it is not relevant to their current difficulties, it is worth bearing in mind that a few years back Malaysian was warned twice about coming into London Heathrow without the required amount of fuel, following the usual post-landing ground checks.

I believe they were told in no uncertain terms that UK landing rights would be rescinded if they were caught again.

An experienced pilot from another airline was quoted at the time as saying that, with the level of fuel they were carrying, if they had to do an emergency climb or avoidance manoeuvre, they would likely leave the tops of the fuel pipes exposed, leading to airlock in the supply. Also it opened up the possibility that they would have to claim priority landing rights at what is the world's busiest airport, screwing up air traffic control procedures.

At the time it was suggested that they were doing this simply to save money. It is this, rather than recent events, that would put me off.

The below information would have been applicable back when MAS encountered these issues at Heathrow. Things have changed since then, in particular radio communication requirements.

I am pretty sure they would have departed legally using an appropriate form of flight planning, approved by both the regulator and the airline. There are a few options made available which then allows the airline to maximise payload whilst ensuring the operation is safe but efficient. The final fuel uplift decision however shall always be the crews.

Increased fuel burn can occur on a long flight due to a multitude of reasons. The crew will try and resolve this situation as best they can whilst continuing on to destination. There may be a decision point on the flight plan where a decision on whether to continue or divert will be made.

At UK airports the statement "no delay expected" could mean that up to 20 minutes of holding may be required. That may well have played a part or holding in excess of 20 minutes would have further accentuated the problem.

If the crew find that fuel levels are getting towards the minimum required they will have a few choices available to them. Those choices will depend on the actual situation on that particular day and time. Weather, traffic and fuel levels will be the major factors on the crews decision on whether to divert or continue holding to ensure they land with fuel above the minimum stated in approved documentation. They will gather all the information and then make a decision.

If you are getting close to lower fuel levels then you would inform air traffic control accordingly. A PAN call indicates a level of urgency. A Mayday call indicates an emergency.

With the low fuel caution you will need to avoid large changes in pitch and power to avoid uncovering the fuel pumps.

Heathrow is busy for most of the day. The controllers do a fantastic job with the amount of traffic they handle. Local knowledge and looking at statistics can help an airline decide on the amount of contingency fuel they should load on board.

Hi,

Would have no problems whatsoever flying with this airline. A disproportionate amount of bad luck for all involved. Could have been any number of airlines affected by either of the losses.

http://www.ibtimes.co.uk/battle-britain-see-how-spitfire-wwii-fighter-planes-are-restored-new-zealand-1456094

Great link Transam,

Amazing work those guys are doing. Most definitely on the wish list if win the lottery !

Crashed MH17 flight 'was 300 miles off typical course

http://www.telegraph.co.uk/news/worldnews/europe/ukraine/10975524/Crashed-MH17-flight-was-300-miles-off-typical-course.html

yes but why?

because it deviated 300 or so miles to avoid a storm cell in the area. Still within accepted aviation corridor.

Hi,

It would be highly unlikely for this aircraft in this region to be deviating 300 miles due to weather. If the weather in the area was as significant as that then a new route would likely be chosen to avoid that area. That decision would be made by the flight planners or crew.

There are lots of these airway systems (roads) traversing the skies in countries around the globe. Airlines will on occasion plan to fly on different airways across a country. Lots of factors will influence that decision. Airspace closure, significant weather or more favourable winds will be some of the reasons the flight planning department will take into account.

We will never be able to eliminate risk completely in commercial aviation, but most airlines around the globe put safety at the top of the list.

Hi,

You make reference to Qantas in your message stating they did not fly over Ukraine. They only fly to London so the route used by them on most occasions will avoid the Ukrainian mainland anyway. On occasion you may pass over Simferopol but that portion of the airspace has been closed for quite a while now so can't be used.

The portion of airspace that the Malaysian aircraft flew through was open so I feel the airline cannot be blamed for this tragedy.

Good Point - agree if the case. I know your a fly guy, so how comfy would you have felt flying over Ukraine with all this helicopter / cargo jets etc being shot down, but your flight planning feels its "ok".

I think i would have preferred the long road. A bit like someone telling you its safe to walk in someones garden who has a vicious pit bull.... it really has to be worth your while to take that risk

Hi,

I would expect most airlines faced with airspace restrictions would act accordingly. Some will choose to avoid the country completely, whilst others will choose to avoid the smaller specific area. That's the case here and unfortunately the threat has been underestimated. Many airlines have been flying through this open portion of Ukranian airspace and have therefore dodged a bullet.

Personally, I would not put myself at risk. If I thought there was a specific threat that would affect the flight then I will wait for an appropriate, much safer option. Based on the information I have seen prior to this tragic situation has been that the Simferopol portion of Ukranian airspace was closed. The other four regions remained open.

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I don't see anyone blaming MH for this tragedy, but it is incredibly bad luck considering what they've gone through recently.

My guess is the Russians are already hard at work sanitising the crime scene, and possibly doing what they can to implicate the Ukrainians.

No doubt American satellites are recording it all.

Well to be fair, if we are talking about the thread, skippybangkok is trying to blame MH and I just don't understand it.

Can everyone be really clear on one point, this was NOTHING to do with MH or negligence on their part. I just do not know how the MH staff are holding themselves together at the moment. Two International incidents both under extremely suspicious circumstances in a matter of months of each other. I truly hope the board can come up with a way of motivating the staff to continue.

This is a complete tragedy as all aircraft accidents are, but again let's make it clear, this was not an accident. I have no idea yet of the exact circumstances but the aircraft was in airspace it was permitted to be in and many other aircraft had already been in. The aircraft would have been squawking the correct codes with it's transponder to display it was a civilian airliner and exactly who it was. After MH 370, i really do not want to hear that the aircrafts transponder was mysteriously switched off. It will be very interesting to hear further information from the 'foreign air traffic controllers' who were removed from their desks just before the incident. If I were them I would be out of Ukraine already!

Putin is a gangster, but I am sure of one thing, he is not stupid. I really hope that the Russians will reveal all the data from the FDR. Prior to the explosion the FDR could tell us if any military aircraft intercepted/escorted it, it would also tell us if any critical systems were tampered with on the minutes leading up to the explosion. Of all the airlines in the world I find it staggering that this incident involved MH. I tend to agree with the Oz PM, this is not an accident it is a crime and I pray for all the victims, their families and the MH staff that the truth comes out very quickly.

its pretty clear from what has been reported this flight was not anywhere near it's previous 10 conterparts of the same call sign were - it was 160 kms off course

http://www.mirror.co.uk/news/world-news/malaysia-airlines-plane-crash-flight-3877002

Thanks Bkkjames..... the headline of the article you posted is exactly my question.

1. Its clear the location it was shot down is only about 50 miles south of the Great Circle route from AMS to KUL ( = mathematically shortest route possible ). very clearly lowest fuel consumption route.

2. Its clear Ukraine ATC said "its OK".....but Ukraine military was not in control of the area which they said "OK". They were OK-ing airspace above territory they did not control military.

3. Its clear most airlines but a few avoided that airspace (i.e QANTAS for many months did not fly over Ukraine )

Question is, who is to blame? The grunt who pulled the trigger , or the person who put the aircraft over that airspace to start off with ? Maybe both, but MAS is not completely innocent.

Why tempt fait ?

RIP to Malaysian Airlines passengers and condolences to their families.

Hi,

You make reference to Qantas in your message stating they did not fly over Ukraine. They only fly to London so the route used by them on most occasions will avoid the Ukrainian mainland anyway. On occasion you may pass over Simferopol but that portion of the airspace has been closed for quite a while now so can't be used.

The portion of airspace that the Malaysian aircraft flew through was open so I feel the airline cannot be blamed for this tragedy.

Very very sad news indeed.

RIP to all onboard.

The information I have with regards to flying within this area is that the Simferopol (Crimea) flight information region is closed, but the other four Ukrainian flight information regions are open. Each airline will decide on which course of action to take when planning particular flights over that region.

The reason for the closure is due to the potential of conflicting information being directed to an aircraft from Russia and Ukraine. That's now moved to a whole new level.

An OP over in the New Forum ...

BANGKOK: -- Bangkok-based budget carrier Nok Air will before the end of the month take delivery of the first of eight Bombardier Q400 NextGen turboprops and in doing so become the first airline in the region to operate the Canadian-made aircraft.

More info here

Nice looking bird with good performance.

What a good job that didn't happen at night!

Agree it's a good job. At night the plane on the ground would have so many flashing lights it might be easier to see.

Hi,

Quite often the aircraft on the ground get lost in the sea of lights and can be more difficult to see.

I think the camera is playing tricks to a certain extent on this video. It looks much closer than it really is.

Questions will however will be asked.

Did the controller clear the aircraft to cross the active runway, and if so did the crew accept the clearance. Did they then move quickly enough. A heavy aircraft taxying responds much more differently than a lightly loaded one and thus can seem like an eternity to get moving.

Did the crew enter the active runway without a clearance.

Did the controller issue the go around clearance or did the crew on short final decide to go around.

Good decision either way and a safe outcome was achieved.

Hi,

Lots of potential threats flying around the world. Communication being high on the list.

Non native English speakers being given a last minute change to an expected clearance can cause issues. Rapid fire communication from the controllers in the USA is a challenge, even to an experienced crew.

Hand flying the departure in busy airspace can put a huge workload onto the other pilot. Call sign confusion, weather, unfamiliarity etc all add in to the potential for making mistakes.

Tragic story.

RIP

Hi,

the findings of this crash have been posted by the NTSB. It makes for interesting reading.

The NTSB determined that the flight crew mismanaged the initial approach and that the airplane was well above the desired glidepath as it neared the runway. In response to the excessive altitude, the captain selected an inappropriate autopilot mode and took other actions that, unbeknownst to him, resulted in the autothrottle no longer controlling airspeed.

As the airplane descended below the desired glidepath, the crew did not notice the decreasing airspeed nor did they respond to the unstable approach. The flight crew began a go-around maneuver when the airplane was below 100 feet, but it was too late and the airplane struck the seawall.

"In this accident, the flight crew over-relied on automated systems without fully understanding how they interacted," said NTSB Acting Chairman Christopher A. Hart. "Automation has made aviation safer. But even in highly automated aircraft, the human must be the boss."

There have been refuelling errors in the past. In 1983, an Air Canada 767 was refuelled incorrectly, du to a change from Imperial to Metric measurements. It ran out of fuel in the air, but the pilot (expertly) managed to glide it to a nearby airstrip, saving the plane and the passengers. MH370 may not have been so fortunatel.

Hi,

All fuel related possibilities which may have contributed to the aircrafts disappearance would have been considered fairy early on.

Khaosai - Since the hydraulic pumps are connected to the core of the turbine,baca use of wind milling I assume you will have some slow hydraulics. I believe 777 is still steel cable from yoke to servo, so should still work

Tywais - if all dead and just on autopilot, I think it would go into a spin either on single engine ops, or when second fail due to rudder and aileron inputs .... Khaosai should be able to confirm if single engine can still be handled by auto pilot.....

As such - looks like a nice smooth landing

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Hi,

The left and right hydraulic systems each have a primary engine drive pump and electrically driven demand pumps. The demand pumps act as a back up to the engine driven pump and also operate due to high system demand. Would windmilling provide some limited system pressure. Possibly, I don't know to be honest. With the dual engine failure scenario the ram air turbine provides centre system hydraulic power to the primary flight control components.

The B777 flight control system is electrically operated. If in the unlikely event of a complete electrical failure then the cables from the flight deck to the stabiliser and a few spoiler panels will enable the pilot to maintain straight and level flight until electrical power is re established.

If one engine flamed out at high level then the thrust asymmetry compensation will apply rudder to maintain the aircraft in balance. The only problem with this situation is that pilot input is required to enable the aircraft to descend to a lower, safer more manageable altitude. That is a very straightforward thing to achieve.

With no pilot input available to enable the aircraft to descend then the aircraft will rely on the flight envelope protection.

First off the auto throttle will "wake up" and increase thrust to avoid getting too slow. If that is not enough, and it won't be at high altitude, then the aircraft will get to the point of stall and then start a controlled descent, maintaining a safe speed to prevent a further stall. Normally pilot input would hopefully have occurred before both of these occur. If no pilot input then the aircraft will continue until impact with the ground.

With a dual engine failure then you have no auto pilot and no flight envelope protection.

I don't know if you or others have the answer to this.Something like 5 years ago a T7 driver was talking to me about TAC, and said that often with an engine failure/flame-out the TAC would shut down and need to be recycled. Apparently, TAC relies on thrust comparisons between the 2 engines, cutting in at 10% differential, but with a complete engine failure, the initial engines parameters after failure are often invalid, causing the TAC to shut down. My question is whether this TAC shut down causes the TAC switch on the flight deck to move to "off", or whether the TAC itself initiates a restart/recycle. If it is the former, and there is no active pilot to press TAC "on", the single engine shut down could immediately become catastrophic.

I should have paid more attention to my friends discussion !

Hi,

This switch does not go to the off position automatically, however the system will automatically disconnect.

The aircraft crew alerting system will indicate that it is no longer working. The crew then follow the check list guidance which ask you to switch it to the off position then back to the auto position to see if it can be reset.

If the message from the crew alerting system disappears then it's working again. If not then manual control inputs are required to compensate for an asymmetric situation.

Your question was, when an airplane encounters all engines failure, does the plane start flipping and crash, or continue to fly while losing height? If it continues to fly, how long does it last and how safe it is to land the aircraft ?

As I have described earlier, the aircraft does not flip or crash. It continues to fly at an optimum gliding speed, a speed much lower than its cruising speed.

However, it may not be able to maintain its cruising altitude but continues to lose height at a rate of about 3500 to 4500 feet per minute. This will give an aircraft, cruising at 35,000 feet about 10 minutes to fly a distance of about 40 to 50 nautical miles. Remember, pilots have been trained to restart/relight the engines whenever they encounter total engine failures. If restarting the engines were unsuccessful, they would have no choice but to carry out a prepared forced landing - just like what the Canadian pilot did to the crippled Boeing 767.

What happens when all engines fail

At the rate of decent you mentioned. 3500 to 4500 feet per minute. How does that look when it comes into contact with the earth's surface ? Catastrophic ?

The rate of descent is not catastrophic alone. The vertical speed component is only 45 or 50 mph ( about 41 knots). However, there is still a horizontal speed component of probably about 230 to 260 mph ( about 210 knots). Without doing the math to figure out the g-force components, I can say that yes it would be quite catastrophic. Think about driving your car and hitting a concrete wall at 45 mph while simultaneously being sideswiped by a train doing 240 mph.

That rate of descent would not be pretty and as you said would be catastrophic. A hard landing is normally defined as a descent rate of 600ft per minute or more.

Khaosai - Since the hydraulic pumps are connected to the core of the turbine,baca use of wind milling I assume you will have some slow hydraulics. I believe 777 is still steel cable from yoke to servo, so should still work

Tywais - if all dead and just on autopilot, I think it would go into a spin either on single engine ops, or when second fail due to rudder and aileron inputs .... Khaosai should be able to confirm if single engine can still be handled by auto pilot.....

As such - looks like a nice smooth landing

Sent from my iPad using ThaiVisa app

Hi,

The left and right hydraulic systems each have a primary engine drive pump and electrically driven demand pumps. The demand pumps act as a back up to the engine driven pump and also operate due to high system demand. Would windmilling provide some limited system pressure. Possibly, I don't know to be honest. With the dual engine failure scenario the ram air turbine provides centre system hydraulic power to the primary flight control components.

The B777 flight control system is electrically operated. If in the unlikely event of a complete electrical failure then the cables from the flight deck to the stabiliser and a few spoiler panels will enable the pilot to maintain straight and level flight until electrical power is re established.

If one engine flamed out at high level then the thrust asymmetry compensation will apply rudder to maintain the aircraft in balance. The only problem with this situation is that pilot input is required to enable the aircraft to descend to a lower, safer more manageable altitude. That is a very straightforward thing to achieve.

With no pilot input available to enable the aircraft to descend then the aircraft will rely on the flight envelope protection.

First off the auto throttle will "wake up" and increase thrust to avoid getting too slow. If that is not enough, and it won't be at high altitude, then the aircraft will get to the point of stall and then start a controlled descent, maintaining a safe speed to prevent a further stall. Normally pilot input would hopefully have occurred before both of these occur. If no pilot input then the aircraft will continue until impact with the ground.

With a dual engine failure then you have no auto pilot and no flight envelope protection.

Having had to do Aerodynamic Stability calculations for final year exam, it left me with years of nightmares complete with LaPlace transformations

To explain simple for stability in pitch , from the nose going backwards the(CG? llowing applies:-

1. Center of a Gravity (CG ) is always in front of main wing center of lift

2. Main wing of course lifts

3. Horizontal stabiliser ( tail ) is a negative wing, meaning it pulls down like a formula one car tail wing.

Only reason you waste fuel on a wing that pulls you down to earth is - stability.

So Aerodynamic stability is easy to now fathom

1. In stable air/ constant speed, is you get gust of wind ( air speed increase ), more lift on main wing and more down pull on tail.

Nose will pitch up

2. If nose pitch up, angle of attack on tail will reduce resulting in less negative lift. Since CG is forward of main wing, this will pull nose down.

So what happens - add more engine power is same as a gust of wind, nose will pitch up. Since there are no "shock absorbers", it will be like a spring which oscillates for a while ( speed / pitch / vs ) will oscillate until new steady state

Simply put

Power controls vertical speed - up/down- alt hold

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Sorry, Skippy, just not what we're talking about. It's not a question of what happens in a gust of wind. It's what happens with both engines out, all the way down to the water that we're concerned with.

So there is a RAT which can provide hydraulic power to the flight controls, even with both engines out. The pilot, if still alive, COULD have attempted a controlled ditching.

If the pilot was not alive, then the question is what would the aircraft do on its own. Would the RAT deploy automatically? If so, would autopilot be restored and provide a "controlled" descent ( e.g., a reasonably stabilized ("stabilized" in terms of predictability and adherence to some programmed set of rules, not "stabilized" as in dynamically stable)? If so, even without a pilot at the controls maybe there could've been something other than a high-speed/high angle/high rate-of-descent impact.

Hi,

RAT will automatically deploy. No pilot means no autopilot restored.

I see. So does that mean flight control surfaces would just freeze in the position they were in when power & hydraulics dropped offline? I can believe that inherent stability characteristics as described by skippy would sort of "kick in" and provide some sort of "best power off glide", provided flight control surfaces can move, but not if they freeze up.

Hi,

The hydraulics won't drop offline but would probably maintain the same position they were in when the generators failed and attempt to maintain trim reference speed (TRS)

You will only have centre hydraulic system pressure available, powered by the RAT. Limited flight control surfaces will be available. Left and right aileron. Right flaperon. Six spoiler panels out of a total of 14. Stabiliser and left elevator.

Will try it if have some free simulator time and see the results, but reckon the up down phugoid motion will be the end result, getting larger in magnitude until impact.

Having had to do Aerodynamic Stability calculations for final year exam, it left me with years of nightmares complete with LaPlace transformations

To explain simple for stability in pitch , from the nose going backwards the(CG? llowing applies:-

1. Center of a Gravity (CG ) is always in front of main wing center of lift

2. Main wing of course lifts

3. Horizontal stabiliser ( tail ) is a negative wing, meaning it pulls down like a formula one car tail wing.

Only reason you waste fuel on a wing that pulls you down to earth is - stability.

So Aerodynamic stability is easy to now fathom

1. In stable air/ constant speed, is you get gust of wind ( air speed increase ), more lift on main wing and more down pull on tail.

Nose will pitch up

2. If nose pitch up, angle of attack on tail will reduce resulting in less negative lift. Since CG is forward of main wing, this will pull nose down.

So what happens - add more engine power is same as a gust of wind, nose will pitch up. Since there are no "shock absorbers", it will be like a spring which oscillates for a while ( speed / pitch / vs ) will oscillate until new steady state

Simply put

Power controls vertical speed - up/down- alt hold

Sent from my iPhone using Thaivisa Connect Thailand mobile app

Sorry, Skippy, just not what we're talking about. It's not a question of what happens in a gust of wind. It's what happens with both engines out, all the way down to the water that we're concerned with.

So there is a RAT which can provide hydraulic power to the flight controls, even with both engines out. The pilot, if still alive, COULD have attempted a controlled ditching.

If the pilot was not alive, then the question is what would the aircraft do on its own. Would the RAT deploy automatically? If so, would autopilot be restored and provide a "controlled" descent ( e.g., a reasonably stabilized ("stabilized" in terms of predictability and adherence to some programmed set of rules, not "stabilized" as in dynamically stable)? If so, even without a pilot at the controls maybe there could've been something other than a high-speed/high angle/high rate-of-descent impact.

Hi,

RAT will automatically deploy. No pilot means no autopilot restored.

...getting OT. Skippy made the statement that the aircraft would after losing both engines simply maintain its last established IAS, which implies whatever pitch angle and rate of descent it takes to maintain that IAS. And he stated immediately prior that all airliners are dynamically stable in all 3 axes. Does "stability" imply this ability to take up & then maintain a constant-speed descent with no power on the aircraft, and thus nothing driving (and further, no movement of) the elevators?

Hi,

so many variables, and as stated earlier it's unlikely both engines stopped at exactly the same time. All this also assumes the aircraft did not achieve a controlled ditching under power.

I would imagine with both engines failed, no autopilot, and no one flying the aircraft then the following may occur:

Pitch down, height loss, acceleration, pitch up, speed loss, pitch down and so on until stall resulting in a large impact with the ocean.

A much less likely scenario similar to the above, but resulting in a much smoother belly contact, wings level. Highly unlikely.

Skippy is saying otherwise. Ya' can't both be right!

Also, the engines may fail one at a time, but the autopilot surely doesn't give up with one good engine, and surely is designed to handle one engine-out (i.e., all the asymmetric thrust implications).

Hi,

I am not saying I am right and skippy is wrong. I am giving my opinion and respect all ideas and opinions on the subject to what may have happened.

If in normal flight control mode the aircraft has the following functions available:

Stall protection, overspeed protection and bank angle protection. If the aircraft automatically goes to secondary mode, or pilot selected direct mode then these will not be available.

The autopilot is only available in the normal flight control mode.

The thrust asymmetry compensation is also only available in the normal flight control mode.

If both engines fail then the normal flight control mode is initially not available. It however can be reconnected by the pilot thus allowing the auto pilot to be re engaged once the auxiliary power unit starts. That however needs fuel too, so the implications of it not being available are obvious.

With both engines failed the ram air turbine (RAT) will automatically deploy. It provides both electrical and hydraulic power. Primary flight control components from the centre hydraulic system will continue to work via the RAT.