* Airbus had 333 net orders in first 11 months
* Planemaker has announced 705 orders in December
* Boeing had 844 net orders by Dec 19, may be nearer 900
* Order race depends on which deals are booked for 2017
By Tim Hepher
PARIS, Dec 29 (Reuters) - Airbus is pulling out the stops to try and take the lead in its annual order contest with Boeing, lining up a spree of billion dollar deals to close a traumatic year dominated by management upheaval and corruption investigations.
Deals announced this week include confirmation of a record 430-jet order brokered by U.S.-based private equity firm Indigo Partners on behalf of four airlines. But analysts said Airbus may have to offer large discounts to close the gap with Boeing.
The Indigo deal and up to 275 other last-minute orders are seen as a swan song for Airbus sales chief John Leahy, who is due to retire in January after roughly trebling Airbus's market share in his 23 years at the helm.
Airbus has endured what insiders describe as a painful year, falling sharply behind Boeing and seeing its sales teams demoralised by the impact of UK and French probes into the use of middlemen by a now-disbanded headquarters unit.
Its share price is nonetheless near record highs as the planemaker recovers from recent production problems.
Looking to retire on a high, Leahy is seen keen to sell at least as many aircraft as the 700 jets Airbus expects to deliver in 2017 - after revising the internal target up from 400 earlier this year when the industry was slowing sharply.
But many observers expect the New Yorker to go further and try to match Boeing, which reported 844 net orders up to Dec. 19 and is believed to be closer to the 900 mark now.
Airbus has announced deals for a total of 705 narrowbody jets since the end of November, lifting its potential catch for the year above 1,000 before adjusting for cancellations.
Recent deals include 100 jets to Delta Air Lines, 50 each to lessors AerCap and China Aircraft Leasing (CALC) and 75 spread between two other airlines.
Whether Airbus completes a surprise comeback depends on how many of the latest orders are net additions to the order book.
Hungary's Wizz Air said its share of the Indigo order, comprising 146 jets, needed shareholder approval.
If all deals announced by Airbus since the start of December are included in the end-year total, then two thirds of the year's business will have been done in the final month, compared with an average of 20 percent in the previous 10 years.
Analysts and industry sources said such a spree could hurt profit margins as the planemaker offers concessions to get deals across the line.
Indigo Partners will have negotiated exceptionally low prices for its block order, while lessors AerCap and CALC were said to be attracted by steep discounts, they added.
"Indigo is a sign of investors boxing up plane orders for airlines, but that's not good for margins as it increases buyers' power," said Teal Group analyst Richard Aboulafia.
Airbus sources said pricing was driven by the size of the deals and denied making unusual concessions.
Both Airbus and Boeing have deep pockets to offer discounts on best-selling narrowbody jets, where they make most profit.
"This industry is above all a volume game," Aboulafia said.
By contrast, it has been a poor year for orders of Airbus wide-body jets. The planemaker has sold 46 so far this year and has been outsold more than three to one by Boeing, whose Dreamliner sales are at their highest since 2013.
Despite doubts over the future of the world's largest airliner, the A380, Airbus still hopes to clinch an order for 36 from Dubai's Emirates. Talks broke down at last month's Dubai Airshow, but have since resumed, industry sources say.
That hasn't prevented Airbus making plans to phase out A380 output if the Emirates deal is abandoned, Reuters reported this week. While others show interest, few can buy in the volumes Airbus needs to commit to keeping its lines open.
However, Airbus is also betting that if Emirates does buy, this will be a catalyst for other sales, Reuters reported.
Airbus described the report as "speculation". (Reporting by Tim Hepher; Editing by Susan Fenton)