- 2B37 checkout
- Attitude gyro
The vertical gyro system is powered by the AC power bus and is located in
the aft cockpit behind the left console. The vertical gyro system is to provide
the pilot with visual indications of aircraft pitch and roll attitudes on
the attitude indicators in both the forward and aft cockpits. The gyroscope
develops, through synchros, pitch and roll signals representative of the aircraft
attitude through 360 degrees roll and +82 degrees pitch.
The erection system incorporates separate systems for pitch and roll. Vertical
reference is established by two gravity-sensitive switches that control a
torque motor for each gyro axis. High or low erection rate of the gyro is
accomplished by applying high or low voltage to the respective torque motor.
A panel-mounted switch placarded FAST ERECT provides fast erection. Pressing
the switch will erect the gyro to within 1.0 deg of pitch and roll within
60 seconds of power application and erect to within 0.5 deg within 2 minutes.
A power failure flag in the gyro will be visible whenever input power is lost.
For training purposes, the aft cockpit attitude indicator may be disabled
from the forward cockpit avionics panel with a switch placarded AFT CKPT,
ATTD GYRO, ON and OFF.
The attitude gyro provides the pilot with constant visual indication of aircraft
pitch and roll. The attitude gyro is your primary attitude instrument. There
are several reasons for this which must be emphasized:
- It is the only direct reading instrument. In other words, it shows exactly
the amount of bank or nose pitch being utilized.
- It shows attitude change immediately. There is no lag in this instrument.
- It directly displays two primary components of aircraft attitude, nose
and wing. Crosscheck instruments include turn needle (rate gyro precession),
balance ball (yaw), RMI, VSI, and airspeed indicator.
The attitude gyro is set on the ground by aligning the arrow on the adjustment
knob with the white mark on the face of the instrument. When airborne,
if it is necessary to reset the instrument, do so only in straight and
level flight at normal cruise (150 kts).
- Instrument lag
All pressure instruments have an inherent lag (i.e., altimeter, VSI, airspeed
indicator). Additionally, the magnetic standby compass tends to either lag
or lead the aircraft’s heading during turns and swings unpredictably in turbulent
air. Only in straight and level flight in smooth air can the magnetic standby
compass be relied upon.
- Instrument scan/attitude crosschecks
Good instrument flight is attained by smooth “attitude control.”
Attitude control is attained by:
- Visualizing and setting a desired power and attitude combination while
studying and controlling the miniature aircraft attitude on the attitude
- rimming the new attitude
- Confirming this attitude by scanning attitude crosscheck instruments.
All attitude changes must be accomplished on the attitude gyro. This means
that you must look at the gyro while you make your adjustments, trim for
the change and continue looking long enough to ensure that the aircraft
will remain in its new position. A common error is to move the scan too
rapidly to a crosscheck instrument before an attitude is actually “set.”
After stabilizing the gyro, then crosscheck other instruments. Remember,
all other instruments “lag” behind gyro movement. So use that “lag” time
to your advantage for setting gyro attitude.
It is mandatory that the student memorize the scan patterns in the FTI,
pages 2-7 and 2-8.
- Cockpit lighting
The interior lighting system consists of individual instruments post lights,
utility lights, console lights, glareshield floodlights, and console floodlights.
All instruments are lighted by post lights and glareshield floodlights with
intensity controlled by two rheostats on the right console. The post-light
and glareshield-light rheostats are located adjacent to each other under a
group placarded INST. The rheostats are placarded LTS (post) and FLDT (floodlights)
and control lighting from OFF through INC to BRT. When the INST LTS rheostat
is turned on, the red WHEELS light, the yellow MASTER CAUTION light, the annunciator
panel lights, and the AOA indexer are dimmed.
The left and right console panels in both cockpits are lighted by individual
panel edge lights and a left and right console floodlight. The edge lighting
is controlled by a rheostat that is placarded LTS under the CONSOLE placard,
and the floodlights are controlled by the rheostat that is placarded FLDT.
Each cockpit is provided with a special multipurpose utility light. These
lights are designed to provide either red or white illumination utilizing
a narrow spotlight beam or a wider floodlight beam. There are portable lights
with a snap-in permanent mounting base and may be detached by simply pulling
the light straight out of the base. Selection of white spot, white flood,
red flood or red spot can be made instantly by turning the front section.
The color may be changed by depressing a button on top of the light while
turning the front section.
The circuit breaker panel edge lights are controlled with a two-position circuit
breaker-type toggle switch placarded PANEL LTS on the circuit breaker panel
in each cockpit. These lights are constant brilliance.
- Instrument checklist
Prior to each flight, it is essential that all instruments and equipment
be checked for proper operation. Prior to the runup area, the student will
have completed the instrument checklist below and will report to the instructor:
“Instrument checklist complete, oxygen 100%, blinker operating
normally, altimeter error less (or more) than 75 feet. Radios and navaids
tuned and set.”
Bring any difficulty in completing the checklist to your instructor’s attention
- Hood installed and operating properly.
- Rudder pedals and seat adjusted.
- Airspeed indicator reading zero.
- Altimeter set (alignment knob set to white tick)
- RMI aligned with magnetic compass.
- Clock set and running.
- Attitude gyro erect and adjusted.
- Vertical-speed indicator reading zero.
- Oxygen equipment checked and blinker operating.
- Battery switch ON.
- Inverter switch to #1 inverter.
- Attitude gyro remains erect in turns.
- RMI tracking properly in turns.
- Turn needle indicating turn in proper direction.
- Balance ball moving freely; liquid damping fluid full.
- Radios and navaids turned on and set.
- Radios tuned (peculiar to 2B37)
- Unintentional instrument flight
Instrument conditions are to be avoided at all times FAMs. If actual
instrument flight is encountered, immediately level you wings on the attitude
gyro and time for 30 seconds. If not VFR at the end of 30 seconds, attempt
to regain visual flight conditions by making a shallow turn (15 degrees AOB)
for 180 degrees to return to the airspace previously in.
Any time the horizon is not distinguishable, in accordance with OPNAVINST
3710.7, you are in IMC. Additionally, if the existing weather conditions
are less than that specified for VMC you are also in IMC. As a result, if
for some reason you find yourself in the above situation “unintentionally”
you must request an IFR clearance so that you’ll be under positive control.
If you don’t, you’ll increase the probability of a midair collision which
makes for a very bad day. IFR shall be conducted to the maximum extent possible.
New Maneuvers for this event:
Straight and level flight
For straight and level flight it is necessary that airspeed, heading, and altitude
be maintained. Again, the power primarily controls the airspeed while maintaining
altitude. It is important in maintaining straight and level flight based on
airspeed to set the correct level flight attitude and support it with the proper
scan pattern. For instrument flight, the attitude gyro is the basic attitude
indicator for nose and wing position. The nose position is crosschecked with
the altimeter and VSI, and the wing position is crosschecked with the RMI. The
airspeed instrument is the performance instrument. Whenever an error in either
heading or altitude is noted, first stop the error and stabilize, then correct
back to proper heading or altitude.
- If off airspeed and on altitude:
If your scan indicates that altitude is being maintained but your airspeed
is slow or fast, you know that a power adjustment is necessary. Remember,
each torque setting given in this manual is a suggested starting point.
- On airspeed and off altitude:
If you note your altimeter is reading 100’ high, yet the airspeed is correct,
you should correct to altitude by reducing power and allow the trim to lower
the nose slightly so as to return to altitude with no increase in airspeed.
Once returned to altitude; reset normal cruise power setting and retrim.
- Off altitude and off airspeed:
If your scan detects a fast airspeed and a small loss of altitude or a slow
airspeed and a gain in altitude, it is obviously due to improper nose attitude.
Stabilize using the attitude gyro; then, correct by trading excess airspeed
for altitude, following by a power increase as necessary to maintain airspeed;
- Precise heading control:
The RMI is your primary reference for heading. In order to maintain a constant
heading, the aircraft should be trimmed for wings level balanced flight. If
a gradual drift of the RMI is detected, level the wings using the attitude
gyro to stop the movement of the RMI. Once the drift is stopped, return to
heading by using a shallow AOB, never a greater AOB than the number of degrees
off heading. Use opposite rudder on rollout.
All considerations for turning flight in the instrument stage are the same as
in FAMs. Establish an AOB on the attitude gyro and maintain that AOB throughout
the turn. Crosscheck the nose position with the altimeter and VSI. Corrections
to maintain altitude are made in the same manner as in straight and level flight.
To prevent turning beyond the desired heading, it is necessary to anticipate
or lead the new heading. A reasonably accurate rule of thumb is to lead with
the 1/3 rule.
If, for example, the AOB is 30 degrees, the rollout should be started 10 degrees
before reaching the desired heading. In this example, when you pass 10 degrees
prior to your specified heading, shift your scan completely to the gyro and
roll out on the gyro. This rule will be used during all turns to specified headings.
- Over rotating the nose as the AOB is established, resulting in a climb.
- Looking away from the attitude gyro before the AOB is set, resulting in
over banking as the wings continue to roll.
- Failure to maintain a level flight scan as the turn progresses, allowing
the nose to fall, resulting in a loss of altitude.
- Failure to roll out on the desired heading due to slow or improper scan
(not looking at the RMI for turn performance and not applying the 1/3 rule).
- Not rolling out on the gyro. The most common error is to watch the RMI during
rollout. Thus, the wings do not level and the nose is raised or lowered.
- Rolling too fast. This prevents proper coordination between nose and wing
Constant airspeed climbs and descents
Nearly all climbs and descents are performed at a constant airspeed or at least
some climb schedule. These particular maneuvers are performed in Vertical Performance
Speed (VPS) during initial instruction and are used as a basis for rate climbs
and descents. The purpose of these maneuvers is to emphasize that nose attitude
controls airspeed in climbs and descents. These descents and climbs are continued
for 1000’ of altitude change, followed by a transition to a Level off and a
constant heading is maintained throughout the maneuver. The nose crosscheck
is the airspeed indicator and RMI is the wing attitude crosscheck. Altimeter
and VSI show performance. Use PAT for all transitions.
Configuration: Enter VPS from normal cruise by reducing power to 300
ft-lbs. Trim right and up as the aircraft decelerates in order to maintain attitude
and heading throughout the transition. Approaching 130 kts, adjust power to
maintain 130 kts, and retrim. The VPS power setting is approximately 550 ft-lbs;
the VPS level flight nose attitude is approximately 1 degree nose up.
- 850 ft-lbs, right rudder. Use peripheral vision to set power.
- As power is added, raise nose to VPS: 4° nose up.
- Trim right rudder, slightly nose down.
- Start attitude scan, IGO report.
- Level off from climb:
- 50' prior to desired altitude, power to 550 ft-lbs, left rudder.
- As power is reduced, lower nose to level VPS: 0° nose.
- Trim left rudder, nose up.
- Reset power.
- Start attitude scan, IGO report.
- 250 ft-lbs, left rudder.
- As power is reduced, lower nose to VPS: 2° nose down.
- Trim left rudder, slightly nose up.
- Reset power.
- Start attitude scan, IGO report.
- Level off from descent:
- 50' prior to Level off altitude, power to 550 ft-lbs.
- As power is added, raise nose to VPS: 0° nose.
- Trim right rudder, nose down.
- Reset power.
- Start level flight scan.
- When directed by your instructor, return to normal cruise by setting
1015 ft-lbs torque (695 ITT max). 2-3 kts prior to 150 kts set approximately
650-700 ft-lbs and retrim, IGO report.
- Not transitioning to VPS
- Not accomplishing entire sequence on the attitude gyro-shifting scan to
attitude crosscheck instruments before transition is complete and trimmed.
- Over correcting the nose attitude for airspeed or making corrections too
rapidly before airspeed has a chance to settle down. Remember the airspeed
indicator lags behind nose movement and it will not react immediately after
a gyro change is made. Retrim.
- Not trimming the rudder, resulting in heading drift.
- Fixating on the torque gauge.
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the webmaster, Bryan Weatherup
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