GregL

Helicopter autorotative aerodynamics are a complex subject! The autorotative force is derived from the relative airflow gained from the vector between the rotational plane and the inflow airflow from below the disc. This resultant vector is further affected by horizontal inflow with forward speed. The S61 used to have an 'ideal' autorotation speed of 70kts IAS which produced a rate of descent of approximately 2500fpm. If the aircraft were to fly the autorotation faster or slower than this then the position on the drag curve would produce a higher rate of descent. Therefore, the closer to the 'ideal' you can get then the lower the rate of descent. If both aircraft are descending 'vertically' then the still air aircraft 'should' land first (for land read crash!) however if both are flying a correct profile then they would both have the same airspeed just the ground speed would be different thus the angle of descent would be different and the rate of descent the same.

I think my best was sub 20 minutes from Antigua to St Kitts. Visual all the way!

Antigua to St Kitts St Lucia to Tobago Antigua to Punta Cana Bahrain to Doha Abu Dhabi to Muscat Maldives to Colombo Quite a few of 'em

The real EFB is a pile of poo anyway. It's very clunky, slow and about as useful as a chocolate teapot. Most of ours have been disconnected. Now, maintenance functions within the ECL, that IS useful, somehow doubt they will appear any time soon though ;-)

Field performance and climbout performance will affect the V1/Vr split the most on the 777. Wet figures in particular will often give you a split. Also terrain constraints in the climbout and intersection departures will often give you a split on performance limiting runways such as Denver. The V speeds can be affected by using 'packs off' take off, 'improved climb' or 'full power' (selecting packs off takeoff will always give you a full power takeoff) to increase the TOPL (Take Off Performance Limit) to allow greater aircraft commercial loading from such performance limiting fields (Denver, Nairobi, Jo'Burg and Mexico City spring to mind!) The FMC will calculate the V figures based upon your weight, outside air temperature, flap setting and trim. These are overwritten by the EFB (if fitted) or computer generated figures. In our company it is forbidden to manually adjust the figures unless calculated from the performance manual for manually calculated V figures. I've been on the 777 for quite a while now and never heard of manually splitting the V figures to be able to call both the V1 and the Vr, neither would I, personally, allow it. Perhaps it is just either the Air Canada SOP or a personal foible of the Captain on the day. (edited to add the correct term TOPL)

It depends upon the operating procedures of the airline. We let the aircraft calculate the Vr and V2 speeds (the aircraft will not calculate v1) when the performance loading is complete then cross check it against a computer generated performance printout from the ACARS. The aircraft generated speeds must be within 3 knots of those provided by the performance computer over ACARS. If not then either the ACARS data sent to the performance computer was wrong or the weights entered into the FMC during the critical data setting procedure were wrong. This enables a cross checking of the take off data to be performed for safety. The performance figures generated by the computer over ACARS are always entered over the FMC generated figures. The MACTOW is entered and the trim setting checked against the stab green band. If the speeds for Vr and V2 are the same then you only need to confirm the FMC data by pressing the relevant LSK. V1 and Vr are often co-incident, the aircraft will call V1 and the non handling pilot will call rotate. On our aircraft there is no auto callout that I have ever heard for Vr. ( I don't know if it is there but disabled as there are a multitude of airline specific options on the 777 systems.) Hope that helps.

Absolutely correct! As Los Pilotos said, our company policy is 'Windshear go-around', apply full TOGA thrust (either manually or through the TOGA switches) then, if the A/P is engaged, monitor, if manually flying, pitch up to 15 degrees, and roll wings level. Ensure the speedbrake is stowed and maintain aircraft config. The gear doors create a massive amount of drag when they drop to let the wheels in, hence the advice is that, in the critical initial phase of the windshear, leave the gear down, the aircraft has enough grunt to overcome the gear drag. Windshear often has two components, especially in a microburst scenario, one going in and one going out with what appears to be normal performance in between. Glasgow often experiences turbulence windshear with a westerly wind as the wind comes down off of the high ground from the west. The standard profile is to fly the windshear until both the pilots are positive that the event has finished (both the primary and secondary) and then to convert the manoeuvre into a standard go-around by calling 'Go-Around, Flaps 20, Positive rate, gear up'. P.S. At most standard landing weights the thing goes up like a rocket!

It's a lovely machine, I might even be tempted out of my 777 shell for this one when we get it. Depending on the routes. Mind you, the idea of ETOPS 350, irrespective of the engine manufacture and the reliability, still gives me collywobbles!!!!! I do miss the table (not so much the 1980's Atari joystick though!).

I bet that one never gets a mention if you want food and a cuppa!!!

Generally it is advised that if you have PCA and the APU running, as is often the case, the packs will be selected off to avoid chattering the flapper valves due to dual input. As far as I am aware the APU generally has more oomph than PCA and, if the packs are left on, will override the PCA. Airbusman330, I've seen the dispatcher at ORD huffing onto the probe or cupping it around a cup of tea to try and get the PCA to blow colder!!!!! From the Fcom: So, as the PCA supplies the cabin distribution system directly there is no chattering and a NRV protects back pressuring of the PCA system if the packs are left in Auto. A self governing system. :-)

The above information on intercepting waypoints on specific headings is invaluable! Often, especially in the Caribbean, you will be asked to intercept beacons on specific radials and the way given by G-CIVA is excellent. Either that or you can drop the beacon into the FIX page and project a radial out and fly that, just don't forget to fly it in TRK and the computer will handle the drift for you! Happy landings.

Yep, that and the fact that the hoses are usually twisted and kinked therefore only letting about 25% of their potential throughput into the aircraft!

I'm not sure why but I know from friends that the Jumbo is a nightmare to cool on PCA and, when you add all the gated aircraft together, the PCA system probably simply isn't up to the heat and humidity. Just my thoughts (PCA doesn't work very well anywhere in my opinion)

A picture paints a thousand words (and avoids ambiguity as has been seen on another thread!!!!) So: Here you go, from the Fcom. the final intercept course is the LSK6R, it WILL drop all waypoints from your current position to that waypoint and give you an automatic extended centreline. Use it when in HDG SEL. Enjoy. Achieved with a single button press and execute.

Very true, this is normally down to noise and environmental issues. Something Hong Kong has never been too bothered about as far as the new airport is concerned!!!! :-D

The 777 APU runs at about 200kg's of fuel burn per hour. As stated above the air-conditioning on pier at Hong Kong is pretty poor with the PCA (Pre Conditioned Air) failing to cool the cabin sufficiently prior to boarding. We, as a crew, have a duty of care to our passengers plus we don't wish them to enter a boiling tube, so we quite often either power up the APU to cool the cabin and disconnect the PCA or just leave the APU running and not bother connecting PCA. Both the GPU and PCA are expensive so it very much depends as to how long the down time is for many companies.

Grief. The example was 'made up' to demonstrate a point. The example does not adhere to any known engine with any 'real world' application it is there merely to prove a point that limitations may be exceeded in the real world but must be checked as a point of safety or may carry lifex penalties. I could have stated 100% bananas or 110% bananas if I wished, it is there for theoretical exercise to carry the point that past a specific limit engineering checks are required. Limits are set by engineers and manufacturers for a whole variety of reasons. Three of the above are perfectly valid ones. The military have a different usage profile to civilian aviation and the engines will be manufactured and limited accordingly. Not all engines are governed within safety limits by FADEC. Have a look at large helicopters where, in the event of engine failure the FADEC/EEC/Hydro-mechanical governor (if fitted) will revert to emergency mode to enable the full max power usage of the remaining engine and will govern at max transient power for up to 5 minutes in some cases after which the engine is rejected. In other aircraft the gas turbine doesn't have FADEC or EEC, one of mine had Teleflex and bodenflex cables to the engine throttle quadrant of a 1500shp gas turbine. Over throttling could cause tripping of the overspeed governor and was, thus, frowned upon. So whilst different they are not contradictory just taken from a wide spectrum of operational requirements. I think you were reading a little too literally and I failed to include that the numbers were purely there for example. Potentially I could have couched it a little better.

Depending on the sim software obviously, but in the aircraft, when you are close to the destination ILS (the ILS shows up < 250nm to go) you can select the inbound course with the following. Dep/Arr page LSK6R will give you the inbound intercept course to the final approach fix for the ILS. eg (something like): INTCPT ILL40 <-- It's a bit quicker than the above but, as stated, I'm not sure what mod state the simulator FMC is.

I was dealing deliberately in generics, you supplied the limits that you put onto your interpretation of what was said. There were no definitive if you look, you supplied them. As far as I'm concerned this conversation is over. Back to the thread.

777-300 has an overhead flight crew rest area over the top of First Class (hence you can't open the overhead bins there!) They consist of two wide, flat bunks, a couple of leather recliner seats, a toilet and sink area and full IFE. :-) On some of our 777-200's the bunks have been retrofitted, in others there is a curtained off cabin with two bunks in there, and, finally, we will often be allocated a seat in the cabin dependant upon the block time of the flight to be flown. The flight attendants rest is in the back over head economy (coach). Specific routes have specific agreements as to what facilities must be available. The heavy crew will always be on the jump seat during take off and landing as it is their responsibility to maintain the general overview for safety reasons on long flights.

Nothing glamorous I'm afraid, it was back in my early rotary days, a Sea King Mk V. Great machine vastly underestimated.

The simple fact is that I use these aircraft every week and I'm not in the slightest bit fussed if I have a GE or a RR. As I'm not an engineer I am not particularly bothered exactly how specific sensors, knobs, wheels and widgets work in the engine either. I know how to use them. I have enough to do with managing the flight, passengers, destination and ATC not to get bogged down in trivia hence I look for a simplistic approach. Many years ago, in the late 80's, I flew a display at Fairford. Afterwards we had to stand on the line and answer questions. I had one gentleman who, honestly, knew far more about my aircraft, where and when it was build, the engines, lift, thrust, weapons etc. etc. etc. What he didn't know was how to fly it and fight it. :-D Please feel free to dig all you want, I don't want to get involved in a nit picking discussion from a thread that was posted for a couple of picces. Enough said.

I guess I'm a victim of 'keep it simple'. The thrust of the engine is primarily derived from the fan. Therefore to get the thrust you have to move mass through it. I never stated that EPR was derived from it? I did stated that it was based upon it. The primary job of the core is to turn the fan. Many years ago, in large helicopters, the engines performance was calculated using power performance index figures based upon the power turbine inlet temperature and the Ng of the gas generator. The difference between these two gave you the overall performance of the engine based upon generator wear and convergent duct erosion to the power turbines. A very similar thing to EPR measuring the pressure across the core before driving the fan. If I set a specific EPR then I can be sure, irrespective of any wear in the engine, that the speed I am driving the fan is constant. I cannot guarantee that with N1, a constant EPR on a new engine will probably deliver a lower N1 than on an older engine. Such is the nature of these thing. My personal opinion is that if I have to go to a pitch power scenario (unreliable airspeed) then EPR is a more stable baseline for me to work with. There are many ways to skin a cat and many of my colleagues prefer to use N1. Horses for courses. We could 'google' and 'wikipedia' this all day but, to be honest, it's totally irrelevant and very pedantic.

Hmm, I seem to remember saying: Followed by the reported N1% that the CFM56 requires. 100% N1 is a baseline, nothing more. I fail to see where I made it a limit? Specific exceedences include manufacturers and operates requirements to operate the engine within a specific governed range. The GE 75B for example has a 'Denver bump' profile which allows extra thrust for departure. The CFM powered Airbus A320 also had this feature. Two buttons behind the thrust levers. EPR will give you the specific thrust of the engine based on mass flow through the FAN. N1 is the rotation speed of the fan. In an 'ideal' world where the fan produces perfect thrust then N1 will equate to thrust, the world isn't perfect and fans aerodynamically degrade over time. EPR will always give you the actual thrust irrespective of the fan wear or other age related deficiencies, N1 will not. Real world.

N1 100% is a nominal RPM given by the manufacturer based upon structural limits and engine wear. N1 100% may be exceeded for specified periods but specific exceedences must be recorded for engineering inspection. Very rarely do big Gas Turbines operate at their max rated thrust! Gas turbines perform far better at high altitude than at sea level but the fan doesn't. N1 100% is a figure given by the manufacturer which, I would assume not being an engineer, gives the best performance to fuel burn for a specified averaged cruising block of altitudes. For example, the CFM 56 normal operation is: 100% N1= 5175 RPM for exceedences: N1 : 106.1-109.0 --- Normal operation to next landing N1 : Over 109.0 --- Precautionary shut down So, I would dare to suggest that max continuous operations would be governed to approx 100% N1 for the sake of safety margin, performance and wear. In the event of engine malfunctions and the requirement to run on a single donk then the margins may be reduced and the N1 increased. So, max thrust is generally (dependant on the manufacturer and type of engine) not attainable at 100% N1 there is a safety margin built in.