The War in the Air, vol. 4

O CO

An incident in October 191 7 raised important questions about the legality of using aeroplanes for dropping propaganda pamphlets. On the 17th of October a recon- naissance and photographic patrol of Bristol Fighters of No. 11 Squadron became involved in a fight with ten enemy aircraft over Cambrai. Two of the Bristols were shot down, and the enemy discovered in one of them, piloted by Second Lieutenant E. Scholtz with Second Lieutenant H. C. Wookey as his observer, military propa- ganda documents, printed in German, descriptive of the happy lot of a German prisoner in British hands and de- signed to create a 'will to desert'. The two officers were taken to the German Second Army head-quarters at Le Cateau and there informed that the German Government had notified the Allies in April 191 7 that the dropping of pamphlets was considered illegal and that airmen found guilty of the practice would be liable to the death penalty.

THE BATTLE OF CAMBRAI

1 The objectives which had been allotted for day bombing were the stations at Somain, Dechy, Douai, Denain, Busigny, and Le Cateau.

REFERENCE

lines of communication of the Third and Fifth Armies. Actually the squadron was given a wide choice of objec- tives to meet different conditions of weather, but it also had orders that attacks were to be concentrated, that is, attacks on a particular target, once begun, were to be continued for several nights. When the weather was favourable, distant objectives were to be bombed. These were listed as of three grades of importance : in the first were five aerodromes and two railway stations (Hirson and Petit Maubeuge), in the second, three aerodromes and three stations (Le Cateau, Bavai, and Landrecies), and, in the third, eight billeting and depot villages. For nights when the conditions were not good enough for distant work, objectives within the Fifth and Third Army reconnais- sance areas, chiefly rest billets, railway junctions, and dumps, were to be bombed in accordance with lists of targets supplied by the staffs of the two Armies.1

REFERENCE

On the 24th of February the squadron attacked alterna- tive short-distance objectives at Montbrehain, and, on the 25th, rest billets in the woods east of Fontaine-Uterte.1 The raid on the rest billets was continuous, all pilots making two or more trips, and 378 bombs of 25-lb. with twelve of 40-lb. weight were dropped. During the attack on the aerodrome at Etreux on the night of the 21st /22nd of February, it was seen that the aerodrome at Seboncourt was lighted up. On the night of the 5th of March, there- fore, Seboncourt was attacked by fourteen pilots of the squadron, but the visibility was poor and the results un- observed. From the 6th of March to the night before the German offensive opened on the 21st, night-flying opera- tions were possible on seven nights when the objectives were chiefly railway communications in the Le Cateau- Busigny area (where air reconnaissances had reported great train movements), and ammunition dumps at Fresnoy-le- Grand, Brancourt-le-Grand, and Premont. On the night of the 1 8th of March the main objective was Etreux aerodrome which was attacked over a period of seven hours by ten pilots, each of whom made two journeys. Bombs were also distributed on the dumps at Bohain and Fresnoy- le-Grand, and on Seboncourt aerodrome.

CHAPTER III. Naval Air Operations from

Landing operations dependent on progress of the battles of Ypres, 1917. Air photographic survey of the landing beaches.

CHAPTER V. The Battles of Ypres, 31st July-

CHAPTER V. The Battles of Ypres, 31st July-

NAVAL AIR OPERATIONS FROM DUNKIRK

Naval air operations from the Dunkirk area in 19 1 7 were governed by three main considerations. These were the activities by U-boats and destroyers based on the Belgian ports, the bombing operations of enemy aeroplanes working from aerodromes in Belgium, and, in the last half of the year, the Allied military offensive in Flanders. The U-boat and destroyer bases at Bruges, Zeebrugge, and Ostend, and the aerodromes from which the German heavy bombing aeroplanes set out to attack London and the south-eastern counties of England, were open to attack from the air, and the systematic bombing of these various targets became possible in the spring of 191 7 with the arrival at Dunkirk of improved types of night and day bombers, that is, the Handley Page and the De Havilland 4. Dunkirk aircraft also co-operated in the general bombing offensive against military targets during the battles of Ypres. To resist the British bombing formations, and for retaliation, the German air strength in the Belgian coast area was progressively increased and demanded a corresponding expansion of the Dunkirk fighting squadrons.

NAVAL AIR OPERATIONS FROM DUNKIRK

to facilitate a landing of troops to wrest the Belgian coast from the enemy. What could be done depended on the progress made by the Allied left flank in France and Belgium. After many earlier disappointments, it seemed that the opportunity would come in 191 7, in conjunction with the British offensive in Flanders, and Vice-Admiral Bacon pushed ahead with his preparations. By the summer of 191 7 his arrangements had been completed, but as the long-drawn-out battle of Ypres trailed to its conclusion, hope drooped, and, by October, the project had been abandoned. Part of the aircraft work in the preparations merits a brief mention for its general rather than its particular interest. The places chosen for the landings of the military force were three beaches, a mile apart, between Nieuport and Middelkerke. The troops were to be landed off long pontoons (500 feet by 30 feet beam), which were to be pushed into position by monitors. Air photographs of these beaches, taken at low water, indicated that they sloped unevenly, and there appeared to be a danger that the pontoons, which were wedge-shaped, might ground on ridges with the surrounding water too deep for the troops to get ashore. To avert this danger, which would jeopard- ize the success of the operation, it was imperative that the beaches should be closely surveyed and this could only be done from the air. The method adopted by Vice- Admiral Bacon was based on the fact that as the tide fell on a calm day the line of water, visible from the air, formed, in effect, a series of contours along the beach. From air photographs taken, at, say, each foot of fall in the tide, from high to low water, it would be possible to plot the whole beach with sufficient accuracy. It was unneces- sary that the timing of the photographs should be so exact as to ensure one-foot contours. So long as the time when the photographs were taken was carefully noted, intermediate positions could be calculated. In a preliminary survey, to get the rise and fall of the tide curves along this stretch of coast, a submarine was sent to lie on the bottom off Nieu- port for twenty-four hours and the height of water above her hull was continuously registered from readings on the depth gauge.

THE BATTLE OF MESSINES

1 For the Order of Battle, Royal Flying Corps, on the 7th of June, see Appendix III. The Corps squadrons which had been raised to twenty- four or twenty-one aeroplanes for the Arras battle had afterwards again been reduced to an establishment of eighteen aeroplanes. Although the War Office had sanctioned a general increase of Corps squadrons to twenty- four aeroplanes, sufficient aircraft were not forthcoming to make this possible.

THE BATTLE OF MESSINES

While these British preparations were being made, the Germans, who were well aware of what was taking place, were also strengthening their air units in Flanders. When the Arras offensive began to slacken, a general move north had begun. Between the 4th of May and the 7th of June Armin's Fourth Army along the front from the river Douve to the sea was increased from fifteen air units (ten reconnaissance and artillery Flights and five fighter Flights) to forty-four (nineteen reconnaissance, eight pro- tection, eleven single-seater fighter, and six bomber- fighter Flights). These units represented a nominal strength of about 300 aeroplanes of which half were fighters. That is to say, the German air strength from Messines to the sea was approximately the same as the Royal Flying Corps strength available for the ten-mile front along the Messines ridge. The total British air strength along the whole front opposed to General Sixt von Armin's army was approximately 500 aeroplanes, and this number was augmented by a few French and Belgian air units

THE BATTLE OF MESSINES

2 The Royal Flying Corps wireless stations with the Second Army artillery were increased from 100 at the end of April to 280 on the 7th of June. Their efficiency was ensured by an elaborate system of inspection and supervision. By strict attention to the details of wireless co-operation it was found possible to provide one wireless aeroplane for every 400 yards of front without undue risk of jamming. This compares with one for every t,ooo yards of front at the battle of Arras.

THE BATTLE OF MESSINES

It will be recalled that about three weeks before, to- wards the end of the Arras battle, aeroplanes had, on two separate occasions, gone 'over the top' ahead of the attack- ing infantry, and, with machine-gun fire and bombs, had helped to demoralize the enemy troops.1 For the Messines battle something similar was attempted, but this time the low-flying attacks were only loosely related to the infantry operations. The pilots were to rove at their will and shoot at any troops, guns or transport which they discovered.2

PREFACE

This volume covers naval air developments and opera- tions in home waters throughout 191 7 and for the first quarter of 191 8. It includes a narrative of the anti-sub- marine work of the various types of aircraft during the period of unrestricted U-boat warfare, and of the diverse operations undertaken by naval aircraft based at or near Dunkirk. The remainder of the volume deals with air warfare on the Western front, beginning with the battle of Messines in June 191 7 and ending with the German offensives on the Somme and on the Lys in March and April 191 8.

CHAPTER IV. The Battle of Messines, 7th-i4th

CHAPTER IV. The Battle of Messines, 7th-i4th

NAVAL AIR OPERATIONS FROM DUNKIRK

BATTLE of MESSINES

THE BATTLE OF MESSINES

THE BATTLE OF MESSINES yth-i4th of June igiy

CHAPTER III. Naval Air Operations from

Landing operations dependent on progress of the battles of Ypres, 1917. Air photographic survey of the landing beaches.

CHAPTER V. The Battles of Ypres, 31st July-

CHAPTER V. The Battles of Ypres, 31st July-

CHAPTER V. The Battles of Ypres, 31st July-

The capture of Passchendaele.

NAVAL AIR OPERATIONS FROM DUNKIRK

Naval air operations from the Dunkirk area in 19 1 7 were governed by three main considerations. These were the activities by U-boats and destroyers based on the Belgian ports, the bombing operations of enemy aeroplanes working from aerodromes in Belgium, and, in the last half of the year, the Allied military offensive in Flanders. The U-boat and destroyer bases at Bruges, Zeebrugge, and Ostend, and the aerodromes from which the German heavy bombing aeroplanes set out to attack London and the south-eastern counties of England, were open to attack from the air, and the systematic bombing of these various targets became possible in the spring of 191 7 with the arrival at Dunkirk of improved types of night and day bombers, that is, the Handley Page and the De Havilland 4. Dunkirk aircraft also co-operated in the general bombing offensive against military targets during the battles of Ypres. To resist the British bombing formations, and for retaliation, the German air strength in the Belgian coast area was progressively increased and demanded a corresponding expansion of the Dunkirk fighting squadrons.

CHAPTER VI. The Battle of Cambrai, 20th

CHAPTER VI. The Battle of Cambrai, 20th

CHAPTER VI. The Battle of Cambrai, 20th

The interest of the battle of Cambrai. Reasons for the battle. Plan of operations. Overwhelming air concentration. No preliminary bombardment. Special air arrangements. Discreet air patrols. Bad flying weather helps surprise. The experience of a German flying officer. The opening of the battle. Mist. Low-flying attacks by single-seater fighters.

CHAPTER VII. The German Offensive, 1918.

Lessons of the Cambrai battle. Schemes for defence. Employment of Royal Flying Corps when army is on defensive. Importance of recon- naissance. Extension of British line. The German plans. Apprecia- tion of German intentions by Fifth Army commander. Views of G.H.Q. Influence of air reports. Value of air photographs. Infantry warned, 20th March, attack would be made next morning.

PAGE

XI. Battle of Cambrai. Ill Brigade, R.F.C. Special Operation

CHAPTER III. Naval Air Operations from

Landing operations dependent on progress of the battles of Ypres, 1917. Air photographic survey of the landing beaches.

CHAPTER III. Naval Air Operations from

Naval Air Co-operation in the Flanders offensive p. 92

CHAPTER V. The Battles of Ypres, 31st July-

CHAPTER V. The Battles of Ypres, 31st July-

NAVAL AIR OPERATIONS FROM DUNKIRK

Naval air operations from the Dunkirk area in 19 1 7 were governed by three main considerations. These were the activities by U-boats and destroyers based on the Belgian ports, the bombing operations of enemy aeroplanes working from aerodromes in Belgium, and, in the last half of the year, the Allied military offensive in Flanders. The U-boat and destroyer bases at Bruges, Zeebrugge, and Ostend, and the aerodromes from which the German heavy bombing aeroplanes set out to attack London and the south-eastern counties of England, were open to attack from the air, and the systematic bombing of these various targets became possible in the spring of 191 7 with the arrival at Dunkirk of improved types of night and day bombers, that is, the Handley Page and the De Havilland 4. Dunkirk aircraft also co-operated in the general bombing offensive against military targets during the battles of Ypres. To resist the British bombing formations, and for retaliation, the German air strength in the Belgian coast area was progressively increased and demanded a corresponding expansion of the Dunkirk fighting squadrons.