Seein g Dou b le Transition fro m Si ng le to Tw in-E n gin e A ircraft Pete r Del V ecc hio CFI, CF II, MEI
Seeing Double
May 19, 2004
Transition to Twins
Slide 1
Outline
Single vs. Multi-Engine
Multi-Engine Terminology
Obtaining a Multi-Engine Rating
Multi-Engine Safety Tips Staying Current and Competent
Summary
Seeing Double
May 19, 2004
Transition to Twins
Slide 2
Single vs. Multi-Engine - Safety
Main benefit of twin: Redundancy
Still have power if one engine quits
Dual vacuums pumps
Dual alternators
Main detriment of twins: If managed incorrectly, that one engine will try to flip the plane over
The large yawing moment caused by the operative engine can cause the plane to enter a spin
Seeing Double
May 19, 2004
Transition to Twins
Slide 3
Single-Engine vs. Multiengine
Single-Engine
Multiengine
lower sex appeal
higher sex appeal
lower useful load
higher useful load
lower climb rate slower cruise
higher climb rate faster cruise
lower service ceiling
higher service ceiling
Seeing Double
May 19, 2004
Transition to Twins
Slide 4
Single-Engine vs. Multiengine
Single-Engine
Multiengine
longer range
shorter range
greater endurance
less endurance
lower stall speed
higher stall speed
lower fatal accident rate
higher fatal accident rate
lower cost
higher cost
operating/maint cost acquisition cost
operating/maint cost acquisition cost
Seeing Double
May 19, 2004
Transition to Twins
Slide 5
Piper Saratoga II TC vs. Seneca V
Saratoga
Seneca
1/6
2/6
Max. Gross Weight
3600 lbs
4750 lbs
Useful Load Payload w/full fuel
1135 lbs 523 lbs
1337 lbs 605 lbs
Cruise Speed (10,000’)
175 kts
182 kts
Service Ceiling
20,000’
25,000
# of Engines/Seats
Seeing Double
May 19, 2004
Transition to Twins
Slide 6
Piper Saratoga II TC vs. Seneca V Saratoga
Seneca
950 nm
828 nm
Endurance
7.8 hrs
5.6 hrs
Fuel Burn Stall Speed (gear/flaps dn)
18.5 gph 63 kts
24.0 gph 61 kts
S.E. Rate of Climb @ S.L.
1175 fpm
250 fpm
Cost New
$456,100
$564,200
Range w/reserve
Seeing Double
May 19, 2004
Transition to Twins
Slide 7
takeoff
decision making
need to keep up with emergency skills
more complex - multiple fuel tanks,determine crossfeed, multiple electrical systems - must what to do if one fails
increases workload
higher speeds further increase workload
Seeing Double
May 19, 2004
Transition to Twins
Slide 8
Arguments Against Twins
More complex
Twice as many engines to fail
Twice as many engines to maintain
Higher fuel consumption
May not be able to maintain altitude
“The second engine will fly you to the scene of the crash”
Example: SE ceiling for Duchess 6200 @ max gross
What percentage of your flight time is spent over Absolute Ceiling?
However, increases to 10000 at 400lbs less
Less efficient
two engines - less efficient, which means more horsepower, which implies more fuel consumption, which means more hp, which implies more weight/etc
Seeing Double
May 19, 2004
Transition to Twins
Slide 9
Arguments For Twins
Higher Performance
Increased Safety
Backup engine!
If emergency procedures practiced
Increased Useful Load
Required For Most Commercial Operations
Bragging Rights
Slipstream produces lift
Seeing Double
May 19, 2004
Transition to Twins
Slide 10
Outline
Single vs. Multi-Engine
Multi-Engine Terminology
Obtaining a Multi-Engine Rating
Multi-Engine Safety Tips Staying Current and Competent
Summary
Seeing Double
May 19, 2004
Transition to Twins
Slide 11
Multi-Engine Cockpit
Beechcraft Duchess Seeing Double
May 19, 2004
Transition to Twins
Slide 12
ME Aerodynamics
Why low performance for SE operation?
Thrust not in centerline (for conventional twin) -> to maintain directional control, must use rudder
More options for CG
Can use nose compartment
W&B calculation same as for SE
Seeing Double
May 19, 2004
Transition to Twins
Slide 13
Straight-and-Level
Seeing Double
May 19, 2004
Transition to Twins
Slide 14
Engine Failure
Seeing Double
May 19, 2004
Transition to Twins
Slide 15
Engine Failure Relative Wind
X
Seeing Double
May 19, 2004
Transition to Twins
Slide 16
Eliminating the Side Slip
X
Seeing Double
May 19, 2004
Transition to Twins
Slide 17
Types of Twins
Light Twin
Check FARs for weights, requirements
Centerline Thrust
Cessna Sky Master
Adams A500
Conventional vs. Counter-rotating
Turbo-Prop
King Air
The P-38 had no critical engine because both propellers rotated outwards. Seeing Double
May 19, 2004
Transition to Twins
Slide 18
Comparison of Twins
Seeing Double
May 19, 2004
Transition to Twins
Slide 19
New V-Speeds All of the standard v-speeds, plus:
VMC - Minimum Controllable Airspeed
VXSE - Best Single-Engine Angle of Climb
VYSE - Best Single-Engine Rate of Climb VSSE - Safe Single-Engine Speed
AIRSPEED
240
MPH
40
220
60 80
200
100
180 160 140
120
Seeing Double
May 19, 2004
Transition to Twins
Slide 20
Other Twin Lingo
Airspeeds
Red Line
Blue Line
Critical Engine
Propeller Terms
Windmilling
Feathering
Counter-rotating
Takeoff Distance
Accelerate-Stop Distance
Accelerate-Go Distance Seeing Double
May 19, 2004
Transition to Twins
Slide 21
Multiengine Glossary
Blue Line Airspeed (VYSE)
Airspeed that gives the best rate of climb with an engine out (VYSE), marked by a blue radial line on the airspeed indicator
If an engine fails in a multiengine airplane, the blue line airspeed gives the best rate of climb or the least rate of descent.
Seeing Double
May 19, 2004
Transition to Twins
Slide 22
Multiengine Glossary
Critical Engine
The engine on a multiengine airplane that would cause the most difficulty in maintaining control of the airplane if it failed in a critical condition of flight, such as takeoff.
To eliminate the critical engine, the right engine on some airplanes rotates counterclockwise while the left engine rotates the moment arm for both propeller disks is clockwise. close to theThus fuselage.
Seeing Double
May 19, 2004
Transition to Twins
Slide 23
Multiengine Glossary
Minimum Controllable Airspeed (VMC)
Lowest speed at which the airplane is controllable with one engine developing takeoff power and the other engine’s propeller windmilling.
The minimum controllable airspeed (VMC) is marked by a red radial line on the airspeed indicator.
Seeing Double
May 19, 2004
Transition to Twins
Slide 24
Multiengine Glossary
Minimum Safe Single-Engine Airspeed (VSSE)
The airspeed recommended by the airplane manufacturer as the minimum safe speed at w hich to perform intentional engine cuts.
Never intentionally cut an engine below theminimum safe SSE single-engine airspeed (V This isafter intended to cuts reduce the accident potential from).loss ofspeed control engine at or near VMC.
Seeing Double
May 19, 2004
Transition to Twins
Slide 25
Multiengine Glossary
Accelerate-Stop Distance
The runway distance required for an airplane to accelerate to V1 or VYSE, lose an engine at that speed, and then slow the airplane to a full stop.
This definition of accelerate-stop distance applies to commuter and air transport category aircraft.
Seeing Double
May 19, 2004
Transition to Twins
Slide 26
Multiengine Glossary
Accelerate-Stop Distance aircraft, >10 occupants, Part 135 ops.)
(small
The runway distance required for an airplane to accelerate to V1, lose an engine at that speed, and slow the airplane to a speed no greater than 35 knots.
I think the accelerate-stop distance should be called the “accelerate-slow distance”, because you don’t have to stop. Even better, it could be called the “accelerate-thensurvive-the-crash” distance.
Seeing Double
May 19, 2004
Transition to Twins
Slide 27
Multiengine Glossary
Accelerate-Go Distance
The takeoff roll distance required for an airplane to accelerate to V1 or VYSE and then continue the takeoff if an engine fails at that speed.
The accelerate-go distance is not provided for all airplanes. This could be an implied admission by the manufacturer that the airplane can not accomplish this.
Seeing Double
May 19, 2004
Transition to Twins
Slide 28
Factors of VMC
Full Power at Sea Level
Cowl Flaps Open
Max Gross weight
Most rearward CG Max bank 5 degrees into good engine
Raise the dead
Critical engine windmilling (or auto-feathered)
Seeing Double
May 19, 2004
Transition to Twins
Slide 29
Outline
Single vs. Multi-Engine
Multi-Engine Terminology
Obtaining a Multi-Engine Rating
Multi-Engine Safety Tips Staying Current and Competent
Summary
Seeing Double
May 19, 2004
Transition to Twins
Slide 30
Training Overview
Main goal: How to handle failure of one engine
Especially on takeoff roll, and just after takeoff
ME airplanes are not tremendously faster than high-performance SE
ME systems are somewhat more complex
Crossfeed
Two engines, vacuum pumps, alternators, fuel pumps, etc.
Synchronizers, yaw dampers, pressurization, strobe-effect indicator, deice, weather radar, oxygen
most me ac use constant speed, controllable pitch, fullfeathering propeller
3/4 plate drag
similar to se except high/low rpm and feathering capability Seeing Double
May 19, 2004
Transition to Twins
Slide 31
Training (cont.)
one major difference is the function of engine oil in the propeller system
expect to spend more time learning the systems of a me ac
ME oil moves to flat pitch, high rpm
dual electrical busses, what happens when one fails?
multiple tanks - mains and aux, left and right, can only crossfeed from mains normally - for this reason, aux tanks should be used early in flight
Seeing Double
May 19, 2004
Transition to Twins
Slide 32
Additional Aircraft Class
MEL = Multi-Engine Land
Requires a checkride
Oral and flight test, but no written
As with any checkride, makes you current for the next two years
Can be added to Private or Commercial
Can also be done as an initial Private or Commercial rating
For example, can have Commercial ME privileges and Private SE privileges
Don’t need to do commercial single maneuvers
If you have an instrument rating, you must perform instrument maneuvers
Two instrument approaches on the practical test: one SE, one ME
Seeing Double
May 19, 2004
Transition to Twins
Slide 33
Private Pilot Requirements
Hours required
Maneuvers required
Seeing Double
May 19, 2004
Transition to Twins
Slide 34
Commercial Pilot Requirements
Hours required
Maneuvers required
Seeing Double
May 19, 2004
Transition to Twins
Slide 35
Multiengine Training Syllabus
FAA Advisory Circular 61-9B
Practical Test Standards
Multiengine Training
Preflight Examination Flight Maneuvers and Procedures
Ground Reference Maneuvers
Flight at Minimum Controllable & Landing Airspeeds
Seeing Double
May 19, 2004
Transition to Twins
Slide 36
Multiengine Training Syllabus
Multiengine Training (continued)
Stalls
Maximum Performance Operations
Control by Reference to Flight Instruments
Use of Radio, Autopilot and Special Equipment
Emergencies
Emergency Operation of Aircraft Systems Engine-Out Emergencies
Seeing Double
May 19, 2004
Transition to Twins
Slide 37
Multiengine Training Syllabus
Engine-Out Emergencies
Propeller Feathering or Engine Shutdown
Engine-Out Minimum Control Speed (VMC) Demo
Engine-Out Best Rate-of-Climb Demo
Effects of Configuration on Engine-Out Performance
Maneuvering with an Engine-Out
Approach & Landing with an Engine-Out
Seeing Double
May 19, 2004
Transition to Twins
Slide 38
Outline
Single vs. Multi-Engine
Multi-Engine Terminology
Obtaining a Multi-Engine Rating
Multi-Engine Safety Tips Staying Current and Competent
Summary
Seeing Double
May 19, 2004
Transition to Twins
Slide 39
Staying Current
FAA Regulations
WVFC Regulations
Seeing Double
May 19, 2004
Transition to Twins
Slide 40
Outline
Single vs. Multi-Engine
Multi-Engine Terminology
Obtaining a Multi-Engine Rating
Multi-Engine Safety Tips Common and New Twins
Summary
Seeing Double
May 19, 2004
Transition to Twins
Slide 41
Safety Tips
Never go below VYSE
Keep current on emergency procedures
With a SE airplane, the decision is made for you if the engine fails
Don’t combine emergencies during training
Seeing Double
May 19, 2004
Transition to Twins
Slide 42
Engine-Out Performance
Title 14 of the Code of Federal Regulations (Federal Aviation Regulations) §23.67
IF OR IF
MGW > 6000 lbs Stall Speed > 61 knots
THEN
Single Engine2 Rate of Climb @ 5000’ .027 × (VS0) Gear & Flaps Up Dead Engine Feathered Cowl Flaps on Good Engine Open
WITH
Seeing Double
May 19, 2004
Transition to Twins
Slide 43
Engine-Out Climb Performance
Aircraft Piper Seneca Piper Aztec Beech Baron D55 RC 500S Shrike Cessna 310
Required ROC
Actual ROC
N/A
0 fpm
N/A 121 fpm
50 fpm 121 fpm
107.16 fpm
129 fpm
110.2 fpm
119 fpm
Source: AOPA
Seeing Double
May 19, 2004
Transition to Twins
Slide 44
Engine-Out Climb Performance
When one engine is lost in a light twin, the loss in climb performance is 80-90%. Airplane
% Loss
Beech Baron 58
80.7
Cessna 310
78.1
Cessna 402B
86.0
Piper Aztec
83.5
Piper Seneca
89.8
Source: AOPA
Seeing Double
May 19, 2004
Transition to Twins
Slide 45
Multiengine Rule #1
Never allow the airspeed to drop below published VMC except during the last few yards of the landing flare, and then only if the field is extremely short.
Source: Richard N. Aarons, FAAAccident Prevention Program FAA-P-8740-25, AFO-800-1079
Seeing Double
May 19, 2004
Transition to Twins
Slide 46
Multiengine Rule #2
A best all-engine angle-of-climb speed that is lower than VMC is an emergency speed and should be used near the ground only if you’re willing to bet your life that one engine won’t quit during the climb.
Source: Richard N. Aarons, FAAAccident Prevention Program FAA-P-8740-25, AFO-800-1079
Seeing Double
May 19, 2004
Transition to Twins
Slide 47
Multiengine Rule #3
Use the manufacturer’s recommended liftoff speed or VMC plus five knots, whichever is greater.
Source: Richard N. Aarons, FAAAccident Prevention Program FAA-P-8740-25, AFO-800-1079
Seeing Double
May 19, 2004
Transition to Twins
Slide 48
Multiengine Rule #4
After leaving the ground above VMC, climb not slower than single-engine best rate-of-climb speed and not faster than best all-engine rate of climb speed. The latter speed is preferable if obstacles are not a consideration.
Source: Richard N. Aarons, FAAAccident Prevention Program FAA-P-8740-25, AFO-800-1079
Seeing Double
May 19, 2004
Transition to Twins
Slide 49
Multiengine Rule #5
Be a skeptic when reading the performance tables in your aircraft owners manual and be doubly sure you read the fine print. Add plenty of fudge factors.
Source: Richard N. Aarons, FAAAccident Prevention Program FAA-P-8740-25, AFO-800-1079
Seeing Double
May 19, 2004
Transition to Twins
Slide 50
Multiengine Safety Tip #1
Don’t even think of spinning a multiengine airplane.
Manufacturers are not required to demonstrate spin recovery for certification of multiengine airplanes
Even if spin recovery techniques are published in the owners manual, they may not work, especially if not started quickly and properly.
Seeing Double
May 19, 2004
Transition to Twins
Slide 51
Multiengine Safety Tip #2
Don’t even think of stalling a multiengine airplane while operating on one engine.
A single-engine stall in a multiengine airplane can turn in to a spin very quickly. (See Tip #1).
Seeing Double
May 19, 2004
Transition to Twins
Slide 52
Multiengine Safety Tip #3
Avoid VMC demonstrations when the stall speed is higher then VMC.
VMC decreases with altitude while the stall speed remains constant. Climbing to a high altitude for a VMC demonstration may cause the airplane to stall before VMC is reached. This is not good. (See Tip #2).
Rather than doing VMC demonstrations at a low altitude, block the rudder pedal, which will cause V MC to increase.
Seeing Double
May 19, 2004
Transition to Twins
Slide 53
Multiengine Safety Tip #4
Don’t use the extra engine to justify taking extra risks, especially with the weather.
A thunderstorm can trash a multiengine airplane just as easily as a single-engine airplane.
Weather related issues are ainmore significant factor in multiengine accident s than single engine accidents.
Seeing Double
May 19, 2004
Transition to Twins
Slide 54
Multiengine Safety Tip #5
Don’t fly IFR in any airplane unless you are IFR proficient in that specific airplane.
If you have both an IFR rating and a multiengine rating, you may still not be proficient flying IFR in a multiengine airplane, especially if an engine fails in instrument conditions or during a missed approach.
Seeing Double
May 19, 2004
Transition to Twins
Slide 55
Multiengine Safety Tip #6
If you must takeoff with a high gross weight, use a longer runway.
Gross weight is the single most important factor affecting climb performance. Single-engine climb performance will be greatly increased with a lower gross weight.
Longer runways allow for safer aborts after T/O emergencies. Avoid intersection departures!
Seeing Double
May 19, 2004
Transition to Twins
Slide 56
Multiengine Safety Tip #7
If you must takeoff on a short runway, reduce takeoff weight as much as possible.
Reducing takeoff weight will reduce ground roll and increase climb performance.
Seeing Double
May 19, 2004
Transition to Twins
Slide 57
Multiengine Safety Tip #8
Perform a pre-takeoff briefing - decide on an altitude, below which the takeoff will be aborted in the event of an engine failure.
It is always better to go through the fence at 50 kts than hit the trees at 120 kts.
The pre-takeoff briefing puts the pilot in the proper frame of mind, removing distractions and preparing to react if problems occur during takeoff.
Seeing Double
May 19, 2004
Transition to Twins
Slide 58
Multiengine Safety Tip #9
Maintain currency on multiengine emergency procedures.
A one hour flight review every two years is not enough.
Consider training to “professional” standards, with flight checks every six months.
Seeing Double
May 19, 2004
Transition to Twins
Slide 59
Adams A500
Six Seats
Speeds
Max Cruise (75% Power) 230 KTAS (22,000 ft)
Stall Speed (VS0) 70 KTAS
Climb Performance
Sea Level, Both Engines 1,800 fpm
Sea Level, Single Engine 400 fpm 15,000 ft, Single Engine 230 fpm
Weights
Max Gross Weight: 6,300 lb
Useful Load:
2,100 lb
Engines: TCM TSIO-550 350HP
41.4 GPH Rich of Peak
35.0 GPH Lean of Peak Seeing Double
May 19, 2004
Transition to Twins
Slide 60
Diamond DA42 Twin Star
Four Seats
Speeds
Max Cruise (80% Power) 181 KTAS (12,500 ft)
Stall Speed (VS0) 56 KTAS
Climb Performance
Sea Level, Both Engines 1730 fpm
12,000 ft, Single Engine
400 fpm
Weights
Max Gross Weight: 3,637 lb
Useful Load:
1,237 lb
Engines: Thielert Centurion 135hp turbo diesel
10.7 GPH Total Fuel Consumption
FADEC, auto-feather
Runs on Diesel or Jet A Seeing Double
May 19, 2004
Transition to Twins
Slide 61
Backup Slides
Seeing Double
May 19, 2004
Transition to Twins
Slide 62