Figuring Basic Operating Weight.

[scubabri]

Does BOW get figured when the aircraft is weighed each 36 months? For a 135 aircraft, where might I find the standard weights or are the extras weighed and added?

sb

 

[onthebeach]

Understanding this subject.

Read and review FAR 135.181, which will tell you what is required as to weighing the aircraft used for 135 ops.

Empty weight is defined by the Aircraft Weight and Balance Handbook, FAA-S-8083-1, 1999, which is available in PDF on faa.gov. However, the Handbook's definition is in conflict with the latest version of the FAR available at the same site, in that the Handbook states that the empty weight includes either undrainable oil, or a full reservoir of oil, depending upon the certification regulation of the aircraft.

But, according the latest FAR 23 and 25 (certification regulations), both state that empty weight will be determined with full oil on board.

Since Basic Operating Weight includes the crew, it cannot be a specific permanent number, because obviously the crew may change on each flight.
This is why FAR 135.185 speaks of empty weight.

As to what is installed on your aircraft, you want to refer to Chapter 6 of your Airplane Flight Manual (AFM), where you will find the airplane's equipment list.

 

[scubabri]

but the BOW uses some assumed numbers for the crew, not actual crew weights, pilot supplies, which are weighed I guess and are assumed to not change, as well as refreshments and other equipment on the aircraft, which again are assumed to not change.

My question is, is this something that is done at the time the aircraft is weighed or can the additional items over the empty wieght be calculated and added by the crew to establish a BOW.

thanks,

sb

 

[charter dog]

Our AFM has a BOW worksheet in the W&B section which may be used to find BOW. The basic empty weight is determined by weighing every 36 months in the manner and configuration specified in the maintenance manual. Our aircraft empty weight includes unusable fuel, normal levels of engine and hydraulic oils and permanent ballast. (The particulars regarding operating fluid inclusion were changed back in the seventies. Some older aircraft may still not include it per their manual.)

The final empty weight, CG location, total moments and % MAC are the starting point for the BOW worksheet. Normal galley supplies, books, movable ballast, standard crew and all other misc. items normally onboard which are not included in the BEW are added according to their weights and station locations. The final tally represents basic operating weight, CG, total moments and % MAC.

Anything carried aboard the aircraft which is not included in the BOW is accounted for as payload on the W&B form for the flight, including non-standard actual crew weights.

The actual particulars of BEW and BOW may vary somewhat between aircraft and operators. The above is just a representative example of how more than one charter company does it with one particular airplane type. With some minor exceptions, this is the way it is generally done.

Best,