Supporting those ground forces were elements of the Royal Iraqi air force, including 63 British, Italian and American-built warplanes equal to or newer than those at Habbaniya. Number 1 (Army Co-operation) Squadron at Mosul had 25 airworthy Hawker Nisrs, export variants of the Audax powered by Bristol Pegasus radial engines. Number 4 (Fighter) Squadron at Kirkuk possessed nine Gladiators. At Baghdad No. 5 (Fighter) Squadron had 15 Breda Ba.65 attack planes, while at Rashid No. 7 (Fighter-Bomber) Squadron could field 15 Douglas 8A-4s, as well as four Savoia S.M.79B twin-engine bombers purchased from Italy in 1937. On paper, at least, the Iraqi air force had the RAF outclassed at Habbaniya.
Smart contacted his ambassador in Baghdad to issue an ultimatum for the Iraqis to start withdrawing from Habbaniya by 8 a.m. on May 2. In that way should they refuse to heed the deadline, the whole day would be available for combat. Smart was still unsure of how far London would support him if he engaged the armed forces of a country not clearly defined as an Axis power. His maddening uncertainty was tardily banished by a May 1 telegram from Churchill: "If you have to strike, strike hard."
That emboldened the harried commander to make the first move. He had learned from a radio message that 10 Vickers Wellington bombers from No. 70 Squadron had arrived at Basra. With expectations of their support, he would launch an airstrike at dawn on May 2. Although an aerial assault against well-dug-in armored forces had never succeeded before, Smart was upbeat, remarking, "They should be in full retreat within about three hours."
Smart refused to withdraw the aircrewmen and least-experienced students from the trenches despite their doubtful ability, even bolstered by 400 Arab auxiliaries, to stop an armored charge. Knowing that their ground crews' availability to service returning machines would be critical in the fight to come, Smart's squadron commanders furtively toured the perimeter late on the night of May 1 and led the necessary personnel away from their fighting positions.
At 4:30 on the morning of May 2, 1941, the first flying machine cranked its engines on Habbaniya airfield. Thirty minutes later 35 Audaxes, Gordons and Oxfords were showering bombs on the Iraqis, joined by Wellingtons of Nos. 70 and 37 squadrons from Basra. The Iraqis were well dug-in on broken ground that provided good cover and concealment, so the British saw few potential targets at first. The Iraqis, unable to draw beads on the airplanes in the darkness, retaliated by shelling the air base, but the gun flashes gave away their positions. The Audaxes dropped explosives on the anti-aircraft gun pits while the Wellingtons' turret gunners strafed them. The Iraqi anti-aircraft gunners used many tracers, again marking their positions for the British airmen to attack or avoid. After bombing from just 1,000 feet for maximum accuracy, the British carefully scanned the plateau for suitable future targets.
As soon as an aircraft landed, one of its two crewmen (they alternated) would hurry to the operations control room, report on the results of his raid and suggest targets for the next flight. Meanwhile, the other crew member would oversee ground personnel in making repairs, refueling and rearming the aircraft. The planes' engines were generally kept running. As soon as the first crew member returned with a new assignment, the two would board their machine and return to the fray.
The Wellingtons performed well on the first day, but being big they attracted the eagle's share of ground fire as well as half-hearted attacks from two Iraqi Gladiators and two Douglas 8As. One damaged "Wimpy" was forced to land at Habbaniya and then set on fire by Iraqi artillery shells; nine other damaged bombers were declared unserviceable when they returned to Basra. Ground fire brought down an Oxford flown by Flying Officer D.H. Walsh, and Pilot Officer P.R. Gillespy's Audax failed to return.
Smart's estimate that the Iraqis would cut and run within three hours proved seriously overoptimistic. By 12:30 p.m., after 7 1/2 hours of almost-constant aerial assault, they were still shelling the base, and at 10 a.m. their air force had joined in, destroying three aircraft on the airfield. One of the Gladiator pilots, Flying Officer R.B. Cleaver, was trying to intercept an S.M.79B when his guns failed, but Flying Officer J.M. Craigie caused a Ba.65 to break off its strafing attack.
By day's end, the British had flown 193 recorded operational sorties -- six per man. The RAF had lost 22 of its 64 aircraft, and 10 pilots were dead or critically wounded, but only a crippling injury was deemed sufficient to send a man to the infirmary.
Although the Iraqis had been sorely hurt and showed no inclination to launch a ground attack, they were still firmly ensconced atop their elevation with a variety of fieldpieces trained on the smoking flying school. Furthermore, that afternoon Iraqi troops invaded the British Embassy in Baghdad and confiscated every wireless transceiver and telephone, leaving the only two significant English outposts in the region isolated from each other.
By that evening, Dudgeon and Hawtrey were the only squadron commanders not dead or hospitalized. They decided that the next day Hawtrey would command all remaining Audaxes and Gladiators from the base's polo field, which was visually screened from the artillery by a row of trees. Dudgeon would direct all Oxfords and Gordons from the cratered landing field.
Meanwhile, the Committee of Imperial Defense had transferred command of land forces in Iraq to Middle East Command, compelling Wavell to assemble whatever elements he could spare into a relief unit, called Habforce, to march the 535 miles from Haifa to Habbaniya. Rashid Ali's leaders also appealed for help, but the Germans were preparing for their invasions of Crete and the Soviet Union, and the Italian response was slow. Only the Vichy French in Syria agreed to send arms and German-supplied intelligence to the Iraqis. They also promised the use of Syrian airfields to any aircraft that the Germans or Italians were willing to commit to Iraq.
On May 3, Smart, noting that the Iraqi artillery had not caused as much damage as he feared it would, called for the RAF to launch some preemptive strikes against the Iraqi air bases. Three Wellingtons of No. 37 Squadron bombed Rashid, also claiming to have shot down a Nisr and damaged another. The Iraqi airmen struck back, but Cleaver attacked an S.M.79B, which he last saw diving away with its left engine smoking. One of the Gordon pilots, Flight Lt. David Evans, developed a novel and risky but effective method of dive-bombing. After the ground crewmen had affixed fuzes with a seven-second delay to the 250-pound bombs, he would remove the safety devices. That meant that if a bomb came loose from its fitting, it would probably explode seven seconds later. After takeoff, Evans would climb to about 3,000 feet and scan Iraqi positions. Then, diving at about 200 mph, he would yank back on the stick and drop a bomb from six to 10 feet over the target -- too close to miss. Seven seconds later, just as Evans made it to a safe distance, the bomb would obliterate the target and rattle his teeth. This method so terrified the Iraqis that they took to their heels without bothering to fire at the plunging Gordon.
Although Rashid Ali's troops kept shelling Habbaniya, they balked at storming the base. Their confidence was further undermined by the arrival of four Blenheim Mk.IVF fighters from No. 203 Squadron on May 3. Eight of No. 37 Squadron's Wellingtons bombed buildings and strafed aircraft at Rashid on May 4 but lost a plane to a combination of 20mm ground fire and an Iraqi Gladiator of No. 4 Squadron. The Wellington crew was taken prisoner. Two Blenheim Mk.IVFs from Habbaniya also strafed Iraqi aircraft at Rashid and Baghdad airfields. At that same time, six Vickers Valentias and six Douglas DC-2s of No. 31 Squadron were flying troops into Iraq and ferrying out civilian evacuees. One of the DC-2s flew into Habbaniya with, among other supplies, ammunition for a couple of World War I–era fieldpieces that for years had stood as ornaments outside the officers' mess. To the garrison's surprise the old guns proved still operable, and when they opened up on the plateau, the Iraqis were convinced the British were being reinforced with artillery. The trainers only flew 53 sorties that day, but they also flew night missions to deprive their besiegers of sleep.
Still, the defenders were suffering much worse than their foes seemed to realize. After four days of combat, just four of the original 26 Oxfords were still battle-worthy. The Audax, Gladiator and Gordon contingents were similarly depleted. Pilots were also becoming even scarcer, as half-trained cadets died in action or suffered from cracked nerves.
On May 6, an Audax returned from a dawn reconnaissance mission with news that the Iraqis were withdrawing. That encouraged Colonel O.L. Roberts of the 1st King's Own Royals, commander of ground forces at Habbaniya, to mount an assault, backed by the Audaxes, to drive the enemy from the plateau. The timing was perfect -- the Iraqis, their morale broken at last, suddenly abandoned the heights in a disorderly withdrawal down the Baghdad road toward Fallujah. Meanwhile, six Wellingtons from No. 37 Squadron hit Rashid again.
That afternoon the British spotted a column of Iraqi reinforcements approaching from Fallujah, which soon ran into the forces retreating from Habbaniya. In complete disregard for military procedure, both groups stopped on the highway, and personnel jumped from their vehicles to confer, leaving all their trucks, tanks and armored cars parked in plain view. At that point, Savile hurled every remaining Audax, Gladiator, Gordon and Oxford he had -- 40 aircraft -- at the bunched-up mass of vehicles. The young airmen in their old planes knew they would not have a better -- or another -- chance like this, and they made the most of it with all the shells and bombs they could carry. The two airstrikes took two hours, with the British flying 139 separate sorties. One Audax was damaged by groundfire, but they left the Iraqi convoy in flames.