Obstacle Clearance Flashcards
what obstacle clearance requirements do single engine class B have?
have no formal requirement for obstacle clearance on take-off but achieve a broad margin of safety as they may not be operated at night or in IMC for public transport
Multi engine class B must clear obstacles by …ft from the end of the … up to …ft
50
TODA
1500
size of the obstacle domain for aircraft with wingspan less than 60m =
60m + half wing span + 1/8 of distance from end of TODA up to max half-width of 300m
size of the obstacle domain for aircraft with wingspan more than 60m =
90m + 1/8 of distance from end of TODA up to max half width of 300m
If flight path is straight or less than 15 degrees turn, max half width of the obstacle domain is …m if flying visually or with same accuracy on instruments, if this accuracy cannot be achieved it is …
For turns of more than 15 degrees the equivalent values are … and …
300
doubles to 600m
600m and 900m
formula for height gain when considering obstacle clearance and given gradient and distance from end of TODA =
see image
what is reference zero?
A point on the ground directly below the aircraft as it passes screen height at the end of the TODR
Class B MEP NTOFP considers an engine failure when?
does not consider an engine failure until entering cloud
Class B MEP NTOFP climb gradients required:
at screen height with all engines operative?
with one engine inop at 400ft above the t/o surface?
with one engine inop at 1500ft above the t/o surface?
the gradient used is net gradient, which is … of the all engines gross gradient plus the unfactored one engine gradient and is calculated using …% of the headwind component and …% of the tailwind component
4%
measurably positive gradient
- 75%
- 77
50%
150%
what are the three segments of the Class B MEP NTOFP?
When would it only consist of two segments?
First segment lasts from the end of TODR, where a/c is at 50ft, to the point it enters cloud and is flown on all engines with the gear assumed to be up
From the cloud base, where an engine failure is assumed, to 1500ft the aircraft is flown engine out, flaps and gear up with the remaining engine on full power. If the a/c has not reached 1500ft before 5 mins has elapsed the remaining engine must be pulled back to MCT for the remainder of the climb – this creates the third segment
would only consist of two segments when the aircraft has reached 1500ft before 5 mins have elapsed, when the power would have to be reduced to MCT
Class A obstacle clearance is …ft in straight flight and …ft in a turn
35
50
The Class A performance planning for obstacle clearance assumes an engine failure at … and net performance – the gross performance reduced by the following factors (depending on the number of engines). Gradient reductions from gross are:
…% for a twin
…% for a three-engine a/c
…% for a four-engine aircraft
Vef
- 8
- 9
- 0
What is the third segment of the Class A NTOFP and what is the minimum height for this?
The assumed loss of an engine means that the aircraft will not be able to both climb and accelerate and must, at some stage, level off to accelerate in order to raise flaps – the lowest height for this is 400ft. The height of the gross aircraft as the net aircraft clears the obstacle is used to determine this
Sometimes called the gross level off height or Ha, for acceleration height
The four segments of the NTOFP for Class A turbojets are?
First segment from end of TODR with a/c at 35ft, to when the gear is up
Second segment lasts from gear up to the gross level off height
The third segment is a level flap retraction segment ending once the a/c is clean and has accelerated to the final segment climb speed
Fourth segment is a climb from flap retraction height to at least 1500 ft
Class A segment 2 climb gradients are -
…% for twin engine
…% for three engines
…% for four engines
- 4
- 7
- 0
