22

Captain Bill Palmer, in his book "Understanding Air France 447" has a section dedicated to answering that very question as it pertains to AF447. Although there is no way to know for certain he puts forward some possibilities. He quotes a commenter on a website: One commenter on the Weather Graphics website’s AF447 article provided this interesting ...


18

The primary reason is availability -- the high pressure fuel pump is running whenever the engine is, while the airframe hydraulic systems may not be available in case of an accessory gearbox failure, hydraulic leak, or maintenance shutoff. Also, this keeps hydraulic lines from needing to be plumbed deep within the bowels of the engine -- this has benefits ...


17

Aerospace Engineering e-Mega Reference shows the following table for two aircraft (the large commercial jet, the B747-100, and the military jet, the C-5A). You can see that it differs quite a lot between the B747 and the C-5 already, so it's hard to give a definitive answer for all aircraft in general. Also, it depends a lot on how you break down the ...


14

What's the main purpose of this detection system even there are brake temperature sensors. Far more often than not, the need for brake temperature sensors is after landing to tell you how hot the brakes are. If you had to use heavy braking upon landing, they're going to be hot. How hot they are tells the captain in part how he needs to taxi and whether he ...


10

Revised answer The ARINC 429 frame is composed of 4 bytes (32 bits numbered by convention 1 to 32 from right to left). Bits 11 to 29, which are the payload of the frame, can represent data using different formats, e.g. binary or BCD data. The label is used to indicate the content of the data field, and which format is used, and is necessary to convert data ...


9

Enhanced Surveillance (EHS) is a variant of Mode S transponder protocol that includes Downlink Aircraft Parameters (DAP) in the information returned by the airborne Mode S transponder. Mode S can be configured as Mode S Elementary Surveillance (ELS) or Enhanced Surveillance. EHS is the concept behind ELS, ELS being a limited implementation. ELS is deemed ...


7

It wouldn't make much sense. By definition "plug and play" would means that the avionics automatically and silently adapts to whether whether the optional device is present or not. This would mean that if the device is physically fitted, but not in contact with the main avionics -- say, a wire might have broken or shaken loose recently -- then the cockpit ...


6

That is up to the civil aviation authority, which in most countries is distinct agency from the investigation board (in USA this is FAA), to decide. They will take into consideration how likely the problem is to repeat, how big risk it would be if it does¹ and as secondary criteria how much work the fix is and how much it will cost. What must be done will ...


6

In aircraft, transmission usually refers to the whole system, that transmits power between two points, say between the MGB and the tail rotor. Gearbox is usually a component of the transmission system (along with shafts, for example) which is used for changing rotational speed. In a sense, a full transmission system is found only in helicopters, and not in ...


5

Irrespective of 737 MAX MCAS, I haven't seen similar decision relying on a single sensor on 777 or on 757. Similarly I found nothing similar on Airbus 320, 330, 340, 350, or 380. On these Airbuses, 3 sensors are used for critical decisions, thus the faulty sensor is isolated by voting the data. If the 3 sensors are diverging (no 2 sensors giving similar ...


4

I will answer this from a US FAA regulations stand point, but you really have 2 questions here Do modern passenger aircrafts like 747/787/A320/A380 have some sub-system The answer to this in certain ways of looking at it is yes. Modern glass cockpit style aircraft use ARINC Data Busses to transfer the data from the sensors to the main flight computers. ...


4

Speed Trim System (STS) is very similar to MCAS and is used on the same aircraft. Moreover, Boeing maintains that it did not have to notify pilots about MCAS because MCAS is a part of STS, running on the same computer and controlling the same surface — the stabilizer. In a way, MCAS is just an extension of the system that already existed on prior versions ...


3

To answer your questions in order: 1) Pitot tubes are certified to withstand icing under particular circumstances: Within a given temperature range, precipitation amount, altitude etc. If they are operated outside of those ranges then the heating systems may not be effective. In the case of AF447 it was also important that they experienced ice crystal icing ...


2

This 1953 issue of Flight International mentions the Messier Ministop, it seems it was shown publicly for the first time at the Salon de Paris, July 1953: A particularly interesting development was the new anti-skid device which is being marketed under the name of Ministop. The device consists of an accelerometer—a free mass rotating with the wheel—...


1

A transmission is something usually used on a car. They have multiple "gears" that allow the engine to rotate at the same speed while the output rotates at progressively higher speeds. Airplanes don't use transmissions (that I know of!). A gearbox is simply a 1-gear transmission. I suppose technically it could be called a transmission. But it usually is ...


1

It would depends on various factors. First is the severity of the issue. If it can cause a accident then the entire fleet of affected aircraft will be grounded until the fix has been certified and installed. If the issue is not that severe then it will depend on how hard the fix is to install. The harder/more time consuming it is the more time is given. ...


1

Plug and play is a standard developed by IBM and Microsoft around the time windows 95 was released. The old Plug N Play standard is an attempt to make device discovery and configuration a zero touch process for end users. The PNP standard has moved on since that time, however I could imagine some computer devices in the avionics bay utilizing USB, ISA ...


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