diff --git a/docs/documentation/analysis/cost_estimation/operating_cost_method.md b/docs/documentation/analysis/cost_estimation/operating_cost_method.md
index 9a8afa6f99cc846952f40779117ef9bba588eda7..44c3da530fad282569fee50c1c419d1fc2df7b73 100644
--- a/docs/documentation/analysis/cost_estimation/operating_cost_method.md
+++ b/docs/documentation/analysis/cost_estimation/operating_cost_method.md
@@ -4,12 +4,12 @@ $$
TOC = DOC + IOC
$$
-!!! note
- Unless explicitly stated, all values are in SI units and all costs in EUR.
-
## Direct operating costs
The Direct Operating Costs (DOC) are directly influenced by the parameters and the aircraft's performance and are commonly used for aircraft evaluation. Therefore, a simplified method for DOC estimation, based on „From Aircraft Performance to Aircraft Assessment“ by J. Thorbeck <sup>[1]</sup>, is provided. The DOC are determined for one year and the entire depreciation period.
+!!! note
+ In many ways, this method reflects a European cost scenario, for example in terms of assumptions on annual utilization, night curfews, but also with regard to personnel costs and fees incurred. The price factors used are therefore stated in EUR. However, as the aviation market is a dollar market, the cost shares are converted into US dollars using an exchange rate of EUR $e$ (user input).
+
Two elements are required for the simplified DOC model: The route independent (fixed) costs $C_1$ and route dependent (variable) costs $C_2$:
$$
DOC = C_1 + C_2
@@ -28,15 +28,16 @@ Those are calculated both, for one year and for the depreciation period.
#### Capital costs
The capital costs can be assumed to be a linear function of the operating empty mass if the influence of the aircraft market is considered negligible:
$$
- C_{\text{capital}} = P_{\text{OE}} \cdot m_{\text{OE}} \cdot (a + f_{\text{I}})
+ C_{\text{capital}} = (P_{\text{OE}} \cdot m_{\text{OE}} \cdot (a + f_{\text{I}})) \cdot e
$$
In which
-- $P_{\text{OE}}$ - price per kg operating empty mass
-- $m_{\text{OE}}$ - operating empty mass
+- $P_{\text{OE}}$ - price per kg operating empty mass in EUR
+- $m_{\text{OE}}$ - operating empty mass in kg
- $a$ - annuity factor in percent
- $f_{\text{I}}$ - insurance rate in percent
+- $e$ - exchange rate (EUR to USD)
The annuity formula, which is based on a modified mortgage equation, addresses both yearly depreciation and interest:
$$
@@ -87,11 +88,11 @@ Both cost shares are determined by the same variables:
That results in the following calculations:
$$
- C_{\text{FC}} = n_{\text{FCC}} \cdot n_{\text{FC}} \cdot S_{\text{FC}} \cdot f_{\text{ESC}}
+ C_{\text{FC}} = (n_{\text{FCC}} \cdot n_{\text{FC}} \cdot S_{\text{FC}} \cdot f_{\text{ESC}}) \cdot e
$$
$$
- C_{\text{CC}} = n_{\text{CCC}} \cdot n_{\text{CC}} \cdot S_{\text{CC}} \cdot f_{\text{ESC}}
+ C_{\text{CC}} = (n_{\text{CCC}} \cdot n_{\text{CC}} \cdot S_{\text{CC}} \cdot f_{\text{ESC}}) \cdot e
$$
The escalation factor
@@ -102,7 +103,7 @@ $$
incorporates the inflation rate ($r_{\text{INF}}$), which encompasses both price and salary adjustments, and the number of years elapsed between the calculation year and the base year for salaries ($y$).
If the depreciation period is used as the time difference, resulting costs are related to the whole depreciation period, whereas a time difference of one year solely results in the costs for the base year.
-The crew complements as well as the average annual salaries are dependent on the stage length:
+The crew complements as well as the average annual salaries (employer gross amount) are dependent on the stage length:
- Regional: ranges less than 500 km
- Short haul: ranges between 500 km and 1000 km
@@ -114,11 +115,11 @@ and can be taken from the following tables:
Segment | Crew complement | $S_{\text{FC}}$ in EUR/y | $S_{\text{CC}}$ in EUR/y |
----------------|:---------------:|:------------------------:|:------------------------:|
-Regional | 5 | 70,000 | 30,000 |
-Short haul | 5 | 120,000 | 30,000 |
-Medium haul | 5 | 160,000 | 30,000 |
-Long haul | 8 | 200,000 | 45,000 |
-Ultra-long haul | 8 | 200,000 | 45,000 |
+Regional | 5 | 80,000 | 50,000 |
+Short haul | 5 | 120,000 | 50,000 |
+Medium haul | 5 | 160,000 | 50,000 |
+Long haul | 8 | 200,000 | 65,000 |
+Ultra-long haul | 8 | 200,000 | 65,000 |
### Route dependent costs
Route dependent costs $C_2$ include all cost components that are directly attributable to flight operations. These include
@@ -146,32 +147,28 @@ A reliable approximation of the number of annual flights can be found using the
- Yearly night curfew hours: $354 \cdot 7 = 2475$
- Yearly operation time in hours: $OT = 8760-2475-273.6 = 6011.4$
-Knowing the time for one flight $FT$ and the block time supplement $BT$ (turn around time) per flight, the number of flight cycles $FC$ can be calculated:
-$$
- FC = \frac{OT}{(FT + BT)}
-$$
-It is assumed that one flight cycle consists of an outbound flight, a turnaround time and a return flight. Consequently, the number of annual flights is calculated as follows:
+Knowing the time for one flight $FT$ and the block time supplement $BT$ (turn around time) per flight, the number of flights per year $n_{\text{flights}}$ can be calculated:
$$
- n_{\text{flights}} = 2 \cdot FC
+ n_{\text{flights}} = \frac{OT}{(FT + BT)}
$$
#### Fuel costs
-The fuel costs depend on the fuel price $P_\text{F}$, the trip fuel mass $m_{\text{TF}}$ (which can be obtained from the payload range diagram (PRD)), and the number of yearly flights $n_{\text{flights}}$:
+The fuel costs depend on the fuel price $P_\text{F}$ (in EUR), the trip fuel mass $m_{\text{TF}}$ in kg (which can be obtained from the payload range diagram (PRD)), and the number of yearly flights $n_{\text{flights}}$:
$$
- C_\text{F} = P_{\text{F}} \cdot m_{\text{TF}} \cdot n_{\text{flights}}
+ C_\text{F} = (P_{\text{F}} \cdot m_{\text{TF}} \cdot n_{\text{flights}}) \cdot e
$$
#### Handling costs
-Handling charges $F_\text{H}$ include charges for loading and unloading, use of terminals and passenger boarding bridges, security checks, and ground energy supply.
-The annual handling fees are charged based on the payload mass $m_{\text{PL}}$ and the number of flights per year. The resulting handling costs are calculated as follows:
+Handling charges $F_\text{H}$ (in EUR) include charges for loading and unloading, use of terminals and passenger boarding bridges, security checks, and ground energy supply.
+The annual handling fees are charged based on the payload mass $m_{\text{PL}}$ (given in kg) and the number of flights per year. The resulting handling costs are calculated as follows:
$$
- C_\text{H} = m_{\text{PL}} \cdot F_{\text{H}} \cdot n_{\text{flights}}
+ C_\text{H} = (m_{\text{PL}} \cdot F_{\text{H}} \cdot n_{\text{flights}}) \cdot e
$$
#### Landing costs
-The annual landing fees $F_{\text{LDG}}$ are charged based on the maximum (certified) takeoff mass $m_{\text{TO}}$ and number of flights per year. The resulting landing costs are calculated as follows:
+The annual landing fees $F_{\text{LDG}}$ (in EUR) are charged based on the maximum (certified) takeoff mass $m_{\text{TO}}$ in kg and number of flights per year. The resulting landing costs are calculated as follows:
$$
- C_{\text{LDG}} = m_{\text{TO}} \cdot F_\text{L} \cdot n_{\text{flights}}
+ C_{\text{LDG}} = (m_{\text{TO}} \cdot F_\text{LDG} \cdot n_{\text{flights}}) \cdot e
$$
#### Air traffic control costs
@@ -187,7 +184,7 @@ The ATC price factor $f_{\text{ATC}}$ considers the fact that the price scenario
The ATC costs are calculated as follows:
$$
- C_{\text{ATC}} = R \cdot f_{\text{ATC}} \cdot \sqrt{\frac{m_{\text{TO}}[\text t]}{50}} \cdot n_{\text{flights}}
+ C_{\text{ATC}} = (R \cdot f_{\text{ATC}} \cdot \sqrt{\frac{m_{\text{TO}}[\text t]}{50}} \cdot n_{\text{flights}}) \cdot e
$$
with
@@ -210,22 +207,22 @@ In the following, only the maintenance costs per flight cycle are considered. Fo
In which
$$
- C_{\text{MRO,AF,MAT}} = m_{\text{OE}}[\text t] \cdot (0.2 \cdot t_{\text{flight}} + 13.7) + C_{\text{MRO,AF,REP}}
+ C_{\text{MRO,AF,MAT}} = (m_{\text{OE}}[\text t] \cdot (0.2 \cdot t_{\text{flight}} + 13.7) + C_{\text{MRO,AF,REP}}) \cdot e
$$
$$
- C_{\text{MRO,AF,PER}} = f_{\text{LR}} \cdot (1+C_\text{B}) \cdot \left[ (0.655 + 0.01 \cdot m_{\text{OE}}[\text t]) \cdot t_{\text{flight}} + 0.254 + 0.01 \cdot m_{\text{OE}}[\text t] \right]
+ C_{\text{MRO,AF,PER}} = (f_{\text{LR}} \cdot (1+C_\text{B}) \cdot \left[ (0.655 + 0.01 \cdot m_{\text{OE}}[\text t]) \cdot t_{\text{flight}} + 0.254 + 0.01 \cdot m_{\text{OE}}[\text t] \right]) \cdot e
$$
$$
- C_{\text{MRO,ENG}} = n_{\text{ENG}} \cdot \left( 1.5 \cdot \frac{T_{0} [\text t]}{n_{\text{ENG}}} + 30.5 \cdot t_{\text{flight}} + 10.6 \cdot f_{\text{MRO,ENG}}\right)
+ C_{\text{MRO,ENG}} = \left(n_{\text{ENG}} \cdot \left( 1.5 \cdot \frac{T_{0} [\text t]}{n_{\text{ENG}}} + 30.5 \cdot t_{\text{flight}} + 10.6 \cdot f_{\text{MRO,ENG}}\right)\right) \cdot e
$$
with
-- $C_{\text{MRO,AF,REP}}$ - airframe repair cost per flight
+- $C_{\text{MRO,AF,REP}}$ - airframe repair cost per flight in EUR
- $f_{\text{LR}}$ - labor rate in EUR/h
-- $C_\text{B}$ - cost burden
+- $C_\text{B}$ - cost burden in EUR
- $n_{\text{ENG}}$ - number of engines
- $T_{0}$ - sea level static thrust per engine
- $f_{\text{MRO,ENG}}$ - engine maintenance factor