1. A-4 Flight Characteristics
A4 Recurrent training
A-4 Flight Characteristics

2. A-4 Flight Characteristics
Review flight characteristics of A-4 aircraft:
Longitudinal characteristics:
Longitudinal control sensitivity
Trim changes with secondary control actuation
Transonic Mach characteristic
High speed dive recovery
Maneuvering performance
Lateral-directional characteristics:
Roll performance
Dutch roll characteristics
Asymmetric stores
Stall, departure and characteristics
Spin characteristics and recovery procedures
Power controls disconnected

3. A-4 Flight Characteristics
Discussion based on:
NATOPS Chapter IV (A-4M and TA-4J)
Naval Air Test Center reports (A-4M and TA-4F)
AFCS flight characteristics unavailable at this time

4. A-4 Flight Characteristics
Longitudinal control sensitivity:
Norm CG/0.85M: 3 lbs/g
Aft CG/0.50M: 9 lbs/g
Trim changes with control actuation:
Gear/Flaps: slight nosedown
Speedbrake: noseup, counterred by interconnnect
Trim sensitivity at low altitude/high speed
With slats locked up, exhibits neutral-to-negative longitidinal stability (pitch-up) at low speed. Conducive to inadvertent stall.

5. A-4 Flight Characteristics
Mild nosedown trim change at 0.85 IMN
Longitudinal control sensitivity and trim sensitivity at high speed
Transonic pitch-up during high-g decel through 0.9 IMN (change in elevator effectiveness). 4 8 12 16 20 24 28 32 36 40
TIME - SEC
FWDAFT
MACH NUMBER
INDICATED
LONGITUDINAL
STICK FORCE LB
ACCELERATION
NORMAL g
pitch-up
During accelerated recoveries from dives at supersonic speeds, a marked pitchup, proportional to existing load factor, will occur at approximately 0.95 IMN. This increase in load factor is partially due to a marked increase in elevator effectiveness when decelerating through 0.95 IMN. After the initial abrupt increase in load factor or pitchup, the load factor will continue to build up at a slower rate as Mach number is decreased below 0.95 IMN, unless the pilot relaxes aft pressure on the stick.
The pitch-up severity depends on the initial load factor or stick position, being most severe for full aft stick. The following are the maximum initial load factors which may be established by the pilot during a decel through 0.85 IMN without exceeding limit load factor. These maxima are for the critical aft cg condition and assume that the pilot maintains constant stick force throughout the pitch-up.
10,000 feet 3.8g
20,000 feet 3.5g
30,000 feet 3.2g
At altitudes above 15,000 feet, and at high load factors, aircraft buffet will be encountered above 0.95 tp 0.98 IMN. This buffet should be heeded as a warning to relax aft stick pressure. If corrective action is applied by prompltly relaxing the aft stick pressure, the pitchup can be appreciabley lessened.

6. A-4 Flight Characteristics HIGH SPEED DIVE RECOVERY
The diving characteristics of the aircraft are normal except when steep dives are conducted in the clean configuration from high altitudes where airspeeds increase into the supersonic range. Under these conditions, elevator effectiveness is reduced and the aircraft’s basic stability becomes high, limiting the g available even with full aft stick. NATOPS dive recovery nomographs are duplicated above. The following are examples of the altitude loss during a dive pullout using a 4g pull after a 1 sec pilot delay, derived from the above tables:
Initial Condition Altitude Loss 30°/300 KTAS 600 ft 45°/450 KTAS 2200 ft
NATOPS also includes the following notes and cautions related to recovery from high-speed dives:
NoteIf difficulty is experienced in recovering from dive, speedbrakes should be opened immediately and throttles retarded in an effort to reduce airpseed and limit altitude loss in the recovery. The maximum speed for fully effective opening of speedbrakes is 440 KIAS. Speedbrakes are partially effective up to maximum speed capabilities of the aircraft; however, a slow uncommanded roll may occur at airspeeds above 440 KIAS due to asymmetric speed-brake extension. Roll is easily countered by small lateral inputs.
If the elevator power system should fail during a supersonic dive, the stick force required for recovery will be so high as to prohibit normal recovery procedures. Use of aircraft noseup stabilizer trim will then become mandatory to effect recovery.
Do not use the horizontal stabilizer as a dive recovery device except in an emergency. A pitchup will occur as the airspeed drops below approximately Mach 0.94, increasing the chance of structural overstress.
If the speedbrakes are used before entering the dive, airspeeds will be limited to lower values where the increase in stick forces will not be severe.
NoteThe speedbrakes will begin to “blowback” at approximately 490 KIAS.
Add the values from these two tables to obtain total lost in altitude from initiation of the dive recovery to level flight.
NOTE
The altitude loss given is for a constant airspeed pullout. Flight tests have shown actual altitude loss to be 1,000 ft to 2,000 ft greater than computed values due to aircraft acceleration at high power settings or steep dive angles.

7. A-4 Flight Characteristics
MANEUVERING FLIGHT
AVAILABLE MANEUVERABILITY
GROSS WEIGHT = 14,721 POUNDS
MAC
The “V-N” diagrams illustrated above depict the maneuvering capability (“g” available) for the A-4 at sea level and at 15,000 ft MSL. The “corner speed” is shown to be about 360 KCAS (0.58 Mach at sea level and 0.74 Mach at 15Kft.). This speed is significant in that it is the minimum speed at which the airplane is capable of achieving the structural limit g, and is also the speed at which the airplane can achieve the greatest turn rate.
Prior to performing any high angle of attack or maneuvering flight, a slat check should be performed using the procedures listed above.

8. A-4 Flight Characteristics LATERAL-DIRECTIONAL CONTROL CHARACTERISTICS
Full, Against Stop
Partial
Normal (Boosted)
Manual
300
Roll performance
°/s (cruise)
30-50°/s (approach)
Dutch roll characteristics:
With yaw damper OFF, Dutch roll very lightly damped (z < 0.2), and easily excited.
Expected to be well-damped (z = 0.3 to 0.6) with yaw damper ON.
Miscellaneous:
Slats: rolling moment with asymmetric deployment

9. A-4 Flight Characteristics
ASYMMETRIC STORES
Flight manual recommendations for landing with asymmetric stores:
Perform straight-in approach
Maintain normal approach AOA, not less than:
115 KIAS for 7,500 ft-lbs asymm
130 KIAS for 12,500 ft-lbs asymm
Put crosswind under heavy wing
Use min rate of descent touchdown
On manual flight controls:
Max 7500 ft-lbs asymm
Min 140 KIAS initial approach speed, 125 KIAS final

10. A-4 Flight Characteristics STALL CHARACTERISTICS
Stall warning: mild airframe buffet 5-15% above Vs, increasing in intensity to stall
Stall characterized by mild nosedown pitching and light lateral-directional oscillation
Recover by:-decreasing AOA with forward stick
-adding full power
-rolling wings level
1g STALL SPEEDS
SPEEDBRAKES RETRACTED
GEAR DOWN

11. A-4 Flight Characteristics DEPARTURE CHARACTERISTICS
A-4’s are not departure prone. Most departures are result of:
Nose-high, low airspeed conditions
Asymmetric slat extension
Proper recovery procedure:
Hold and visually check controls neutral laterally and slightly aft
Reduce power below 80 percent RPM
Ensure pitch trim 0-4 deg nose up
During post-stall gyrations (PSG), pilot must accept the random roll/yaw oscillations and maintain neutral controls. Control inputs (intentional or inadvertent) will prolong the departure and possibly result in spin entry.

12. A-4 Flight Characteristics
DEPARTURE
For any departure from controlled flight:
Hold and visually check controls neutral, with stick neutral to slightly aft
Lock harness
Reduce throttle below 80%
Check elevator trim 0 to 4 degrees nose up
Check flaps up, speedbrakes in
Check altitude. If out of control passing 10,000 ft AGL, EJECT
Positively recheck controls neutral

13. A-4 Flight Characteristics
SPINS
Spin entry usually requires pro-spin controls to be applied and maintained.
Following inadvertent departure, do not apply spin recovery controls until spin confirmed!
sustained yaw rate
low airspeed (below 200 KIAS)
pegged AOA
Certain post-stall gyrations (PSG’s) are easily confused with an inverted spin. Differences are that:
AOA oscillating
airspeed continually increases
If airspeed is increasing through 200 KIAS, the aircraft is definitely not spinning.
maintain controls neutral
monitor AOA, airspeed and altitude
commence dive recovery as airspeed increases through 200 KIAS
if residual roll at 200 KIAS, stop the roll with aileron then commence dive recovery

14. A-4 Flight Characteristics
UPRIGHT SPINS
The A-4 exhibits two types of upright spins:
Steep oscillatory (most common)
AOA: 20 to 30 units
Turn needle: Pegged in direction of spin, but may come off peg occasionally as yaw rate hesitates
Airspeed: Usually increases as spin progresses (may indicate faster than 150 KIAS)
Flat (least common)
AOA: Pegged at 30 units
Turn needle: Pegged in direction of spin
Airspeed: Stabilized 50 to 150 KIAS
Typical upright spin data:
Rotation rate 4 to 14 sec/turn
Altitude loss 2000 to 7000 ft turn
Rate of descent 20,000 to 35,000 ft/min

15. A-4 Flight Characteristics INVERTED SPIN CHARACTERISTICS
Most common A-4 spin mode is inverted spin:
Oscillatory, extremely disorientating
Recovery complicated by poor A-4 restraint system
Characteristics:
AOA: Near zero units
Turn needle: Pegged in direction of spin
Airspeed: Stabilized 50 to 150 KIAS
Typical inveted spin data:
Rotation rate 3 to 4 sec/turn
Altitude loss 800 to 1200 ft turn
Negative load factor over 2.5g possible

16. A-4 Flight Characteristics SPIN RECOVERY PROCEDURES
Maintain controls positively neutral until recovery is effected or both angle of attack and turn needle are pegged, then apply and maintain recovery controls. The recovery controls for an erect spin are full rudder against the spin (opposite direction of the turn needle), full aileron with the spin, and longitudinal stick position from neutral to slightly aft. When spin rotation stops, neutralize all controls.
The recovery controls for an inverted spin are full aileron and full rudder against the spin (opposite direction of the turn needle). Longitudinal stick position must be neutral to slightly aft; forward stick will impede recovery
The ailerons are the primary recovery control and aircraft response will occur in the form of roll in the direction of hte applied aileron. Spin rotation will slow or hesitate as the aircraft rolls erect, however, this should not be mistaken for spin recovery. The aircraft will frequently continue thhe inverted spin after momentarily rolling erect. Maintain anti-spin controls until there is a positive indication of spin recovery, i.e. AOA other than pegged and airspeed increasing rapidly.

17. A-4 Flight Characteristics SPIN RECOVERY PROCEDURES
Maintain controls positively neutral until recovery is effected or both angle of attack and turn needle are pegged, then apply and maintain recovery controls. The recovery controls for an erect spin are full rudder against the spin (opposite direction of the turn needle), full aileron with the spin, and longitudinal stick position from neutral to slightly aft. When spin rotation stops, neutralize all controls.
The recovery controls for an inverted spin are full aileron and full rudder against the spin (opposite direction of the turn needle). Longitudinal stick position must be neutral to slightly aft; forward stick will impede recovery
The ailerons are the primary recovery control and aircraft response will occur in the form of roll in the direction of hte applied aileron. Spin rotation will slow or hesitate as the aircraft rolls erect, however, this should not be mistaken for spin recovery. The aircraft will frequently continue thhe inverted spin after momentarily rolling erect. Maintain anti-spin controls until there is a positive indication of spin recovery, i.e. AOA other than pegged and airspeed increasing rapidly.

18. A-4 Flight Characteristics FLIGHT WITH POWER CONTROLS DISCONNECTED
Power System Manual Operative Control
°/s (cruise) As little as 10°/s
Roll performance °/s (approach) at 300 kts/S.L.
Longitudinal control 3 lbs/g (norm CG/0.85M) lbs control force: effectiveness/ 9 lbs/g (aft CG/0.50M) 0.96M
sensitivity <0.85M
Power control disconnect above 300 KIAS or Mach 0.80, whichever is lower, should be avoided if at all possible. Reduce thrust and open speedbrakes to decrease Mach to this value before disconnecting. Trim aircraft laterally prior to disconnect, if possible. The aircraft is subject to strong wing dropping tendencies above mach 0.90, with the boost disconnected. Available rate of roll with maximum pilot effort in this speed range may be insufficient to overcome wing dropping tendencies. Although the aileron tab retains some effectiveness, the slow speed of operation of this tab makes it difficult to keep up with the random wing dropping. Wing dropping tendency disappears as airspeed is reduced to Mach 0.85, and available roll rate from pilot input forces increase, making the aircraft once more controllable.