Exercise 19 part B. Introduction to Instrument Flying – Limited Panel / Conventional Instruments
INTRODUCTION TO INSTRUMENT FLYING – LIMITED PANEL /CONVENTIONAL INSTRUMENTS: AIR EXERCISE
1.TURN COORDINATOR CHARACTERISTICS
- Looping error
- Leveling wings (Rate 1⁄2 in opposite direction)
2. REVISION OF FULL PANEL
- S&L, climbing, descending, Rate 1 level turns (Point out performance instrument indications)
LIMITED PANEL – BASIC MANOEUVRES
- Think attitude – remember “neutral point” Stress SMALL control inputs
1.STRAIGHT AND LEVEL
- Altimeter – check Attitude – adjust pitch A/R
- Turn coordinator – check for wings level
- Ball – balance
- Compass – for heading (ONLY in wings-level, balanced flight)
- Trim – when aeroplane settled
2.CLIMBING AND DESCENDING
- Power – set
- Ball – balance
- Attitude – change
- ASI – check
- Attitude – adjust pitch
- A/R Compass – for heading
- Trim – when aeroplane settled
Leveling Off
- Attitude, power, trim – basic technique unchanged
3.RATE 1
TURNS Timed
Turns
- Roll to Rate 1, balance, back-pressure
- Start stop-watch
- Roll out on time (10 secs/30°) Adjust A/R
Compass Turns
- Establish Rate 1 turn
- Monitor compass
- Allow for compass errors: A.N.D.S (U.N.O.S), no corrections on east and west as long as aircraft is not accelerating or decelerating
- Adjust A/R
Stress: possibility of major heading errors on roll-out
4.UNUSUAL
ATTITUDES Nose Low
- Recognition: IAS – high/increasing,
- Altitude – decreasing, VSI – ROD
- Recovery:
- Power – idle
- Unload any excess “g”
- Level wings (TC – Rate 1⁄2 in opposite direction)
- Ailerons neutral
- Pitch to level attitude (yoke to neutral point as altimeter slows) – avoid “snatch pulls”
- Power – as required to stabilize IAS
- TC – confirm wings level (zero turn), adjust A/R
- Ball – balance
- Refine safe straight and level
Nose High
- Recognition: IAS – low/decreasing
- Altitude – increasing, VSI – ROC
- Recovery:
- Power – full
- Unload any excess “g”
- Pitch to level attitude (yoke to neutral point as altimeter slows) Level wings (TC – Rate 1⁄2 in opposite direction)
- Ailerons neutral
- Power – as required to stabilize IAS
- TC – confirm wings level (zero turn), adjust A/R
- Ball – balance
- Refine safe straight and level
Nose Level
- Recognition:
- IAS steady
- Altitude – steady
- Recovery:
- Power – leave
- Unload any excess g
- Level wings
- Refine safe straight and level
INTRODUCTION TO INSTRUMENT FLYING – LIMITED PANEL: AMPLIFYING NOTES
GENERAL
- For the Commercial Pilots License (CPL) and the Instrument Rating (IR), the following two requirements exist:
- Candidates must demonstrate, during the skills test, the ability to fly the aircraft with a failure of the primary flight instruments – the Attitude Indicator and Directional indicator if using conventional instruments (i.e. the aircraft must be flown on “Limited Panel”), or the PFD (i.e. the aircraft must be flown on standby instruments, such as the Aspen), if using glass cockpit.
- Specifically, students must be able to fly the following basic maneuvers with information from only the ASI, VSI, altimeter, direct reading compass and a rate gyro instrument (the turn coordinator):
a. Straight and Level
b. Level Rate 1 turns onto specified headings
c. Climbs and Descents
d. Recoveries from unusual attitudes
BEFORE FLIGHT
a. Turn Coordinator – principles of operation and looping error
b. Direct Reading Compass – errors
c. VSI – lag
THREAT AND ERROR MANAGEMENT
- Any flight instrument failure has potentially serious safety implications: first the opportunity to cross-check one instrument against another is degraded and, second, any subsequent instrument failures may leave a pilot insufficient information to fly safely in IMC. Stress the need for conscientious cruise checks to detect vacuum pump failure and cross-checking instrument indications to guard against insidious failures. Remind your student, too, that, even if flying in VMC, he should consider whether the flight can be continued safely with the remaining serviceable instruments or whether he should divert to a suitable airport. When practicing this exercise during training, you must ensure that you have sufficient height to recover from the exercise safely, especially unusual attitudes.
DURING FLIGHT
- Demonstrate the effect of looping error in the turn coordinator (and the need to “unload” before using the turn coordinator) and the need to roll to Rate 1⁄2 in the opposite direction to achieve wings level. Then revise basic maneuvers on full panel to remind your students of the performance instruments’ indications for each one.
- Normal maneuvers
Cover the Attitude indicator and Directional indicator to fail the relevant instruments, and revise performance instrument indications of normal maneuvers (using visual references), including regaining Straight & Level.
Then teach:
1.Straight and level (At cruise power)
Confirm correct power set – adjust if necessary. Use altimeter rather than VSI to check for level. If not level, make SMALL elevator input, hold for a second or two then return yoke to neutral point. Allow aeroplane to settle in new pitch attitude; while it is doing so, check turn coordinator and stop any turn with small aileron movements. Re-check for level and correct if required. Once your student has mastered the basic technique, then teach re-gaining and maintaining specific altitude, heading and IAS datums. With respect to heading, remind the student that, because of the compass’s acceleration and turning errors, it is pointless checking the compass unless the turn coordinator indicates zero rate of turn. Therefore to correct small heading errors, teach assessing how long it will take at Rate 1 (3°/sec) to regain datum heading, selecting a Rate 1 turn, counting the required number of seconds and then stopping the turn, using the turn coordinator. Allow the aeroplane to settle (for at least 5 secs) before checking the compass. Refine the heading if necessary.
2.Climbing and descending
Stress the similarities with visual and full panel flying:
a. Power – set as required; balance
b. Attitude – make a pitch change to an assumed attitude; hold it, let the aeroplane settle, check ASI and make further small pitch changes, A/R to achieve target IAS. Teach also the cruise climb.
c. Trim – elevator and rudder
3.Rate 1 Turns
Teach both timed and compass turns:
a. Timed Turns
Calculate the time required to turn to the new heading at Rate 1 (3°/sec or 10 secs for every 30°). Roll to a Rate 1 turn, then start the stopwatch. Roll out after appropriate time. Allow aeroplane to settle and refine heading A/R.
b. Compass Turns
Turning errors do not affect the compass when passing east and west, so teach scanning the compass to anticipate the required heading by about 5°. Turning errors are maximum on north and south.
Teach:
ANDS (Anticipate North; Delay South) / UNOS (Undershoot through North, Overshoot through South), starting the roll-out between 20° and 30° early for a northerly heading and overshooting the indicated roll-out heading by the same amount for a southerly one. Stress that the behavior of direct-reading compasses in turns is unpredictable and highly variable and your student should not be surprised if, on roll-out, there is a large heading error. He should re-calculate the correction required and make it methodically. Because of the uncertainties of compass turns, recommend your student to use timed turns, if faced with limited panel flying for real.
Stress that, to maintain an attitude, only two instruments are required:
Altimeter and turn coordinator for straight and level (with glances at the compass to check datum heading).
ASI and turn coordinator for climbs and descents (with glances at the compass to check datum heading and the altimeter for level-off).
Altimeter and turn coordinator for Rate 1 turns (with glances at the compass, A/R to check for roll-out heading).
- Unusual attitude recoveries
Stress that the aim of unusual attitude recoveries, particularly on a limited panel, is to recover to SAFE flight – essentially Straight and level within ± 10 kts of cruise IAS. Until this has been achieved, the actual heading is not important.
Nose Low
Teach how to recognize a nose-low unusual attitude:
- High and/or increasing IAS
- Decreasing Altitude/ROD on
VSI Then teach recovery:
- Power to idle
- Unload any excess “g”
- Roll wings level (turn coordinator indicates Rate 1⁄2 in opposite direction)
- Ailerons neutral
- Pitch smoothly towards level attitude (return yoke to neutral point as altimeter slows) – avoid “snatch pulls”
- Adjust power as required to stabilize IAS
- With elevators neutral, confirm turn coordinator shows wings level (zero turn); adjust A/R
- Regain/refine required datums
Nose High
Teach how to recognize a nose- high unusual attitude:
- Decreasing IAS (often also low)
- Increasing Altitude/ROC on
VSI Then teach Recovery:
- Apply full power
- Unload any excess “g”
- Pitch smoothly towards level attitude (return yoke to neutral point as altimeter slows)
- Roll wings level (turn coordinator indicates Rate 1⁄2 in opposite direction)
- Adjust power as required to stabilize IAS
- Regain/refine required datums
Note: Many books/flight schools teach that the Nose High recovery action is “Power, PUSH etc. ”
Merely pushing can rapidly turn a nose-high unusual attitude into a nose-low one which is no help at all! The aim must be to relax any back-pressure in order to unload excess “g” so that the aeroplane will not stall and ailerons can be used to level the wings. Indeed, once the “g” is unloaded, there is no urgent need to level the wings, so that pitch and roll can be done together.
Level Turns
In this situation, the turn coordinator will show a turn in excess of Rate 1 and the heading will be changing rapidly but IAS and altitude will be stable. If level is being maintained, then “g” is being applied, so teach leaving the power as it is, unloading the “g” then rolling to Rate 1⁄2 in the opposite direction. Let the aeroplane settle and then refine datums.