SlimHeader

facebook_page_plugin
×
PPL Video Lectures (10 Jul 2020)

PPL Video Lectures covering Aerodynamics, General Knowledge, Performance, Meteorology And Navigation are now available through our website see front page for details.

× Welcome to the CPL Performance question and answer forum. Please feel free to post your questions but more importantly also suggest answers for your forum colleagues. Bob himself or one of the other tutors will get to your question as soon as we can.

Basic Empty Weight vs Empty ACFT FRM Flight Manual

  • brook
  • brook's Avatar Topic Author

brook created the topic: Basic Empty Weight vs Empty ACFT FRM Flight Manual

Hi Bob,

Just want to clarify the following:

The supplement on Page 18 has a sample load sheet for Echo, which lists the Basic Empty Weight (BEW) as 1992 kg.

Returning to the first weight based exercise on page 5.7 (BT Perf Issue 6) it states "Empty Weight from flight manual" as 1970 kg.

Are we not talking about the same Echo Aircraft?

Brook
#1

Please Log in or Create an account to join the conversation.

  • brook
  • brook's Avatar Topic Author

brook replied the topic: Basic Empty Weight vs Empty ACFT FRM Flight Manual

Could it be that the weight from the flight manual is the weight from the worked Weight and Balance Sheet - as expressed in the Table (Gross Weight KG) RATHER than the unworked Basic Empty Weight?

For now I am just using the weights you have calculated on face value which work fine.

Brook
#2

Please Log in or Create an account to join the conversation.

  • Posts: 1169
  • Thank you received: 3

Richard replied the topic: Basic Empty Weight vs Empty ACFT FRM Flight Manual

Hi Brook,

In real life, each individual aircraft will have its own BEW entered in the flight manual. This will be the actual weight of that exact aircraft and it doesn't matter if it is a PA28, a C172 or an Echo. Even though two aircraft may be the same model and type, they will still be individually weighed and their BEW may not be the same at all, depending on their configuration.

When we use various weights for Echo aircraft in the questions, we are still talking about an Echo type but each question will refer to a particular example of an Echo type. You can't assume a standard BEW because there isn't one. .

Cheers,

Rich
#3

Please Log in or Create an account to join the conversation.

  • brook
  • brook's Avatar Topic Author

brook replied the topic: Basic Empty Weight vs Empty ACFT FRM Flight Manual

Thanks Rich,

Reading you 5 on the different ACFT types, but I think my question was more in the case of that particular question, when it stated "from the flight manual" having just referenced the same echo ACFT i went looking to the supplement for this as a fixed BEW for this ACFT. But in this case the Echo DOES have a BEW of 1992 as taken from the top row of the the ITEM list on page 18 of the supplement.

I am mentally flexible to accept that the BEW could come in different forms (values), the only question was in reference to THIS specific echo, using the supplement.

So maybe if I invert the question for the purposes of the exam, where would I be expected to need this PARTICULAR figure of 1992 kg for the EXAM? Maybe I need to press on for the Weight and Balance section to find out?

BP
#4

Please Log in or Create an account to join the conversation.

  • brook
  • brook's Avatar Topic Author

brook replied the topic: Basic Empty Weight vs Empty ACFT FRM Flight Manual

Hi Richard - Oops - I now see where I went wrong, it was the terms.

The BT manual mentions EMPTY ACFT weight (I was associating mentally with BEW) from Flight Manual - which is different to Zero Fuel Weight (ZFW), which is what we have been working with not BEW, however the other gotya was that I also associated empty aircraft with BEW ie BEW plus pilot (think I am good now :-)

Sorry about that!

Brook
#5

Please Log in or Create an account to join the conversation.

  • hews16
  • hews16's Avatar

hews16 replied the topic: Basic Empty Weight vs Empty ACFT FRM Flight Manual

Hi Richard

I encountered some questions in the exam along the lines of: an aircraft with a gross operating weight of 2020 and IU 520 is loaded for take off as follows:

(insert a list loading data)

Then, later in the qurestion also mentions row 2 seats are removed and then asks for how many addition pax etc we can carry.


My questions are around the terminology as this is what is making me lose marks in this exam:

- "loaded for takeoff" - does this mean that is the weight of the 2020 is the weight at the runway thus ignore the loading data given?

- alot of questions referred to operating weight, instead of BEW. Do we take this to be the same as BEW?

- if the "loaded for takeoff" figure of 2020kg and IU 520 is given, and then later on the question it mentioned that the seats *have been removed* is an adjustment for seats to be made or is this just a trick to see if you will remove them again?

Thank you
#6

Please Log in or Create an account to join the conversation.

  • John.Heddles
  • John.Heddles's Avatar
  • Offline
  • ATPL/consulting aero engineer
  • Posts: 477
  • Thank you received: 45

John.Heddles replied the topic: Basic Empty Weight vs Empty ACFT FRM Flight Manual

Some observations -

I don't have Bob's books so I can't comment on their content

a sample load sheet for Echo, which lists the Basic Empty Weight (BEW) as 1992 kg. BEW is whatever the originating weight control officer (WCO) wants it to be. Hence, for it to make sense, it has to be defined somewhere. The end user cannot just make up the BEW configuration.

it states "Empty Weight from flight manual" as 1970 kg. EW is a little more tightly controlled. The starting point definition is given in CAO 100.7 - see www.legislation.gov.au/Details/F2018C00475 There is some wriggle room so, again, the EW has to be defined to make a great deal of sense. This should occur on the load data sheet or in the weight and balance pages of the POH.

Are we not talking about the same Echo Aircraft? Each individual aircraft will have its own specific declared empty weight and CG data. This will have been determined either by weighing or calculation and will change periodically.

they will still be individually weighed Generally but not, necessarily the case. Often we run the data via calculations based on previous data and configuration change data.

which is different to Zero Fuel Weight (ZFW) EW will figure in the calculation of ZFW but, apart from that, the two are not related.

gross operating weight This could mean anything but normally would be read to mean the aircraft loaded gross weight ready for operations.

"loaded for takeoff" This will mean whatever the writer intends. However, one probably would interpret it to mean something along the lines of the gross weight at the start of the takeoff run.

a lot of questions referred to operating weight Again, the term should be defined in context otherwise it can mean whatever the writer wants it to mean.

the seats *have been removed* The question (or the empty weight data) should have defined what seating configuration was included in the EW. Then one takes it from there.

Engineering specialist in aircraft performance and weight control.
#7

Please Log in or Create an account to join the conversation.

Time to create page: 0.199 seconds